bluuebunny/crossref_metadata_2025 huggingface dataset:
On the Inhibition of Transmission to the Dorsal Spinocere‐bellar Tract by Stretch of Various Ankle Muscles of the Cat
Authors: Jansen J. K. S. , Nicolaysen K. , Walløe L.
Published: December 2008

Dorsal spinoccrebellar tract neurones activated from primary endings of muscle spindles (la DSCT units) are adequately excited from one muscle or a closely synergistic group of muscles. Inhibitory effects by stretch or contraction of other muscles have been examined in anesthetized cats. Consistent inhibitory effects were obtained from the gastrocnemius‐soleus (GS) muscle on la DSCT units of the flexor digitorum longus muscle (FDL) and the tibialis anterior‐extrnsor digitorum longus (TA‐EDL) muscles. The inhibition of TA‐EDL units was mainly inducrd by GS contraction. The FDL Ia units were inhibited by passive stretch of GS. It is suggested that GS tcridon organs were responsible for the inhibition of TA‐EDI. units and that GS primary endings were responsible for the inhibition of FDI, units. Thus, there appears to be a high degree of specificity also in the inhibitory actions on the DSCT neurones.
The Effect of DOPA on the Spinal Cord 7. Reflex activation of static γ‐motoneurones from the flexor reflex afferents
Authors: Grillner S. , Hongo T. , Lundberg A.
Published: December 2008

In unanaesthetized spinal cats reflex activation of γ‐motoneurones (to a flexor muscle) from the flexor reflex afferents (FRA) has been assessed from the discharge recorded in muscle spindle afferents. After injection of L‐DOPA the resting discharge frequency increases in afferents with secondary endings and volleys in the FRA evoke a longlasting acceleration of the discharge in these afferents. On the basis of previous experiments showing that spindle afferents with secondary endings are activated from static but not from dynamic γ‐motoneurones it is inferred that static γ‐motoneurones are spontaneously active and reflexly activated from the FRA after an injection of DOPA. It has been confirmed that in the acute spinal cat, not treated with DOPA, there is no or little evidence for reflex activation of static γ‐motoneurones from the FRA and it is postulated that the reflex pathway to static γ‐motoneurones is inhibited in this preparation. The results are discussed in relation to other reflex effects evoked from the FRA.
Intracellular Ion Concentrations in Single Crayfish Axons
Authors: Wallin B. Gunnar
Published: December 2008

A method for simultaneous determination of membrane potential and intracellular concentrations of sodium, potassium and chloride in single nerve axons is described in detail. Only 3–5 × 10‐‐9liter axoplasm is required for the ion analyzes and consequently it has been possible to take 2 samples from the same axon. This allows for a comparison of the intracellular ion compositions at different external conditions with good accuracy. The normal ion concentrations in crayfish giant axons are found to be (in mM ± S. E.) Na 17A k 0A, K 265 ± 1.8 and C1 12.7 ± 0.4, indicating that probably none of the ions is distributed in electrochemical equilibrium. It is also shown that the distributions of sodium and potassium are directly dependent on an ouabain sensitive metabolic pathway but that this does not seem to be the case for chloride.
The Relation between External Potassium Concentration, Membrane Potential and Internal Ion Concentrations in Crayfish Axons
Authors: Wallin B. Gunnar
Published: December 2008

In single crayfish axons simultaneous determinations were made of membrane potential and intracellular concentrations of sodium, potassium and chloride at different external potassium concentrations. When the external potassium level was varied from 2–150 mM. internal potassium concentration remained fairly constant. At the same time internal sodium concentration decreased with more than 50%whereas internal chloride level increased 10 times. These ion changes were accompanied by a considerable volume increase. From the data it was calculated that a net inward movement of potassium, chloride and water had occurred while a slight outward transport of sodium was noted at lower external potassium levels. When axon volume increased, observations were made indicating an increased intracellular hydrostatic pressure. In terms of the constant field equation, it appears as if the ratio Pc1: Pkand possibly also Pna: Pkincreares when the axon is potassium depolarized.
Position and Velocity Sensitivity of Muscle Spindles in the Cat.: IV. Interaction Between Two Fusimotor Fibres Converging on the Same Spindle Ending
Authors: Lennerstrand Gunnar
Published: December 2008

Position and velocity responses have been measured during the co‐activation of two indentified fusimotor fibres influencing the same primary or secondary ending in the ankle extensor or flexor muscles of the cat. The effect of double‐fibre activation has been compared with that of stimulating the participating single‐fibres in isolation. During the activation of a dynamic‐static combination complete ‘occlusion’ was usually encountered in the steady discharge at ‘zero’ extension, in the position sensitivity and in the velocity responses to length decrement. Larger responses than any of the two individual actions occurred in the response to dynamic length increment. In the dynamic‐dynamic and in many of the static‐static double‐activations the responses were indistinguishable from those of single‐fibre stimulation at higher stimulus frequency. Other static‐static combinations gave rise to ‘averaging’ of the two single‐fibre effects; this was seen in the position sensitivity and in the velocity responses particularly during static I—static II co‐activations. Possible modes of fusimotor interaction in the spindle are discuesed.
Fusimotor Effects on Position and Velocity Sensitivity of Spindle Endings in the External Intercostal Muscle of the Cat
Authors: Andersson Bengt F. , Lennerstrand Gunnar , Thoden Uwe
Published: December 2008

Position and velocity responses of spindle endings in the external intercostal muscle of the cat have been determined in the absence and in the presence of fusimotor fibre stimulation at a constant rate. The length input signal had triangular wave form. A close functional resemblance was found between intercostal and leg muscle spindles: primary and secondary endings could be separated among intercostal afferents with the same methods that have been used in leg muscles; dynamic and static fibres were discerned and the fusimotor effects on position and velocity sensitivity were the same as in the hind limb; the ratio between dynamic and static fibres was about 1: 3, i.e. the same as in the hind leg. Some dissimilarities existed: the number of ‘intermediate’ endings was larger in the intercostal than in the leg muscles; position and velocity sensitivities were generally larger in intercostal endings. These discrepancies are discussed. As a general conclusion it is stated that a spindle model elaborated from studies on leg spindles can easily be modified to account also for intercostal spindle behaviour.
Localization of Gastrin Activity in the Gastric Antrum1
Authors: Broomé A. , Fyrö B. , Olbe L.
Published: December 2008

Gastrin activity was determined in sections, cut parallel to the surface, of the antral mucosa and submucosa of cats and dogs and in the aboral corpus mucosa of dogs and man. The maximal gastrin activity in the antrum was found in the basal 2/3 of the gland crypt region of the mucosa. The superficial 1/3 of the antral mucosa of the cat contained no gastrin activity, whereas in the dog traces of activity were found in this part of the mucosa. Extracts from the submucosa of the cat antrum contained no gastrin activity, but in the submucosa of 1 dog out of 3 low activity was found. The results suggest that the gastrin cells are localized predominantly in the region of the middle and basal parts of the gland crypts of the antral mucosa in the dog and cat. In the corpus mucosa immediately oral to the visualized antrum‐corpus boundary, no gastrin activity was found in 3 dogs and activity was present in only 4 of 14 doudenal ulcer patients. Thus the gastrin cells do not seem to be present in the corpus mucosa of dog or man, but the occasional finding of gastrin activity in the most aboral part of the acid secreting gastric mucosa of man speaks in favour of a dentate, or sometimes notchy, antrum‐corpus boundary.
Gastrin‐Like Activity in Different Parts of the Gastro‐Intestinal Tract of the Cat
Authors: Emås Svere , Fyrö Bengt
Published: December 2008

Mucosal specimens from different parts of the gastro‐intestinal tract of cats were extracted for gastrin according to the method of Komarov. Extracts were also prepared from the mucosa of the antrum and proximal duodenum according to a modification of a method of Gregory and Tracy. The extracts were assayed for gastrin activity on nonanesthetized gastric fistula cats. Gastrin‐like activity was found in the mucosa of the antrum and the proximal duodenum using either method of extraction. Gastrin‐like activity was also found in most extracts from the cardiac region of the stomach. The gastrin‐like activity of the extracts from the cardiac region and the proximal duodenum was 5–10 per cent of the antral activity. No gastrin‐like activity was detected in the acid secreting part of the stomach, in the middle and distal parts of the duodenum, in the jejunum, colon or pancreas.
Rapid Uptake of Radiostrontium in Sperm
Authors: ÅBerg B. , Crabo B. , Ekman L. , Löw H. , Nyberg J. A.
Published: December 2008

85SrCl2 was administered to rams and semen collected. At 18–30 hrs after the i.v. administration of the radionuclide there was a maximal concentration in the spermatozoa. Already five hrs after the administration the spermatozoal content of 85Sr was higher than the seminal content. From the higher content in the spermatozoa than the seminal plasma it was concluded that there might be a considerable uptake of 85Sr in the spermatozoa after the ejaculation. This was also shown to be the case when 85SrCl2 was added to fresh sperm in vitro.
Potentiation by Smooth Muscle Stimulants of the Hypogastric Nerve — Vas Deferens Preparation from Normal and Castrated Guinea‐pigs
Authors: Sjöstrand Nils O. , Swedin Göran
Published: December 2008

It is shown that a variety of smooth muscle stimulants cause marked potentiation of the motor response of the isolated vas deferens to hypogastric nerve stimulation. The substances used were: adrenaline, noradrenaline, acetylcholine, histamine, serotonin, angiotensin, bradykinin, Substance P and barium chloride. The doses producing this potentiation were in most cases 10–1000 times lower than those necessary to cause a direct contraction of the vas deferens. There were no clearcut differences between castrated and normal animals. Oxytocin and vasopressin were without effect while different prostaglandins (PGE1, PGF1and a crude PG preparation) caused inconsistent responses.

Possible mechanisms for the potentiation are discussed and it is suggested that the most probable explanation is a direct effect on the smooth muscle, but an effect on the transmitter stores of the postganglionic adrenergic neuron cannot be ruled out. Possible functional implications are further discussed.
Monoamine Oxidase in Sympathetic Ganglia of the Cat
Authors: Consolo Silvana , Giacobini Ezio , Karjalainen Kristian
Published: December 2008

The monoamine oxidase (MAO) activity of sympathetic ganglia and isolated ganglion cells of the cat has been studied by a micromodification of the radiochemical method of McCamanet al. (1965a) using (14C) tyramine. The superior cervical, stellate and coeliac ganglia showed a high MAO activity, the coeliac having almost twice the activity of the others. The 6th and 7th lumbar and the 1st sacral ganglia showed lower and approximately the same activity. No significant change in MAO activity could be detected in the lumbo sacral ganglia three to four weeks after denervation.

The 7th lumbar ganglion was used for the single cell experiments. 73 per cent of the ganglion cells had measurable MAO activity with a range from 1 to 41 moles of product x10‐12/hr (mean ±S.E. =5.5±0.57). The results support the previous suggestion that the sympathetic ganglia of the cat contain two distinct cell populations; firstly, a cholinergic population, representing in L7about 10–15 per cent of the ganglion cells, characterized by the presence of ChAc, high concentrations of AChE and the absence of monoamine fluorescence and MAO activity; secondly, an adrenergic population, about 73–88 per cent of the ganglion cells, which exhibits fluorescence for noradrenaline and MAO activity, contains low or moderate AcChE and no measurahle ChAc activity.
Migration of Acetic Acid and Sodium Acetate and Their Effects on the Gastric Transmucosal Ion Exchange
Authors: Flemström G. , Frenning B.
Published: December 2008

The kinetics of the disappearance of acetic acid and sodium acetate from the stomach during secretion and secretory arrest was studied in anesthetized cats. Model experiments were also performed in which the solutes diffused through a cellophane membrane. On instillation of acetic acid into non‐secreting stomachs, the hydrogen ion concentration decreased significantly more rapidly than the acetate concentration (p<0.05). The increase in the combined sodium and potassium ion concentrations was significantly greater than the increase in the chloride ion concentration. Thus, in addition to molecular diffusion of acetic acid, exchange diffusion took place between hydrogen ions and sodium ions. A small amount of secretion masked this exchange. The acetate disappeared more rapidly on instillation of acetic acid than on installa‐. tion of sodium acetate. Acetic acid increases the ionic permeability of the gastric mucosa and has inhibitory effect on secretion. It has been reported that this secretory inhibition persists for up to 24 hrs. By repeated instillation experiments in the cat it was found that the permeability effects of a 30 min installation of 170 mM acetic acid did not persist for longer than 90 min. Sodium acetate per se probably had no effect on the ionic permeability of the gastric mucosa. It is suggested that the permeability increasing effect of acetic acid is related to transient intracellular accumulation of the diffusing acid. Epithelial abrasion that would give rise to an increased permeability by decreasing the diffusion distance requires restoration of the surface epithelium within 90 min and in fact, no abrasion was observed as an affect on acetic acid on the mucosa.
Mode of Binding of Histamine and Some Other Biogenic Amines to a Protamine‐Heparin Complex In Vitro
Authors: ÅBorg Carl‐Hugo , Uvnäs Börje
Published: December 2008

Protamine and heparin form a water‐insoluble complex (PHC) at pH 7. This complex has the ability to bind sodium, histamine and monoamines electrostatically. Titrations have suggested the PHC to be formed by a linkage between the guanidino groups of the protamine and the sulphuric acid and most of the carboxylic acid groups of the heparin. The cationic binding properties of the PHC may be assigned to the terminal COO group of the protamine poly‐peptide chain. The qualitative similarities in the cationic binding properties of the PHC and rat mast cell granules are discussed, with special reference to the mechanism of histamine storage in the mast cell granules.
In Vivo and in Vitro Studies of the Regulation of Palmityl‐CoA Synthetase Activity in Rat Liver
Authors: Farstad Mikael
Published: December 2008

An assay system is described to evaluate the palmityl‐CoA synthetase activating capacity of particle‐free supernatant from different sources. With relatively small amounts of tissue, the activating capacity was proportional to the amount of supernatant present. The palmityl‐CoA synthetase activity in whole homogenates of rat liver was reduced after feeding with sucrose, and increased after fasting. The palmityl‐CoA synthetase activating capacity of rat liver supernatant was also significantly increased after fasting. MgCl2increased the inactivation of microsomal palmityl‐CoA synthetasein vitro, NaCl and NaF reduced the inactivation, and ATP prevented any inactivation. CaCl2, but not KCl, also reduced the inactivation invitro. Inactivated microsomal palmityl‐CoA synthetase was partially re‐activated by incubation with particle‐free supernatant and ATP. The results suggest that two forms of palmityl‐CoA synthetase may be interconvertible through reversible phosphorylation, catalyzed by two different enzymes, viz. the supernatant activating factor and a phosphoprotein phosphatase.
Renal Excretion of Chloride, Bromide and Thiocyanate during Water Diuresis
Authors: Trautner Mads , Wieth Jens Otto
Published: December 2008

The purpose of the present investigation was to examine the suggestion advanced by Saugman (1957) that differing mechanisms of renal tubular reabsorption of chloride and bromide might be detected by studying the anion excretion during water diuresis. Simultaneous excretion of Cl and82Br‐was therefore studied before and during water diuresis in 10 normal human subjects. The excreted fraction of filtered bromide was invariably 30–35 per cent lower than that of chloride, independently of serum bromide concentration (range 0.001–10 meq/litre), excretion percentage of chloride (0.3–2.4 per cent), and of the rate of urinary production (0.6–14.7 ml/min). It was concluded that there is no evidence that the renal reabsorption distinguishes selectively between chloride and bromide.

Simultaneous determination of chloride, bromide, and thiocyanate excretion confirmed that only the excretion of thiocyanate is increased during water diuresis.

The ultrafiltrability of the three anions was determined and considered when the filtered amounts were calculated. The ratios between anion concentration in ultrafiltrate and serum water were: chloride 1.02, bromide 0.98 and thiocyanate 0.77.
DIFFERENCE IN CARDIAC ADRENEBGIG INNERVATION BETWEEN HIBERNATORS AND NON‐HIBERNATING MAMMALS
Authors: NIELSEN KAI C. , OWMAN CHRISTER
Published: December 2008

It is well‐known that the cardiac resistance to reduction in temperature is markedly different in hibernators and non‐hibernating mammals. For example, ventricular fibrillation never occurs in hibernating animals, whereas this the usual terminal event preceding death in non‐hibernators subjected to deep hypothermia. The reason for this difference is not understood.

The present study was undertaken to investigate whether the difference in cardiac resistance to lowering of the temperature could be explained by some difference in the terminal adrenergic innervation apparatus of the heart. The adrenergic transmitter was demonstrated by fluorescence microscopy of formaldehyde‐treated preparations and by spectrofluorimetric analysis.

The number and distribution of adrenergic nerve terminals in the atria of the hibernators (bat, hedgehog, and thirteen‐lined ground squirrel) resembled that of the non‐hibernating animals (mouse, rat, guinea‐pig, cat and also the badger). Both groups of animals possessed a very dense adrenergic innervation of the sino‐atrial and atrio‐ventricular nodes. Intensely fluorescent, catechola‐mine‐containing “chromaffin” cells regularly occurred in the atria of all animals. No adrenergic ganglia could be demonstrated.

The ventricles of the non‐hibernating animals were well supplied with adrenergic nerve terminals running both to the vascular system and to the myocardial muscle cells. This contrasted sharply with the distribution of fluorescent nerves in the ventricles of the hibernators: only scattered terminals were found in the bat, and those present invariably accompanied blood vessels. The ventricles of the ground squirrel and hedgehog received a fairly large number of adrenergic nerves, but they ran almost exclusively in relation to the vascular system.

The findings demonstrate a fundamental difference in the adrenergic nerve supply to the myocardial muscle fibres in the ventricles of hibernators compared with non‐hibernating mammals: the almost complete lack of adrenergic innervation in the myocardium of hibernators may be one explanation for the higher resistance of these animals to lowering of the body temperature.
HISTOCHEMICAL DEMONSTRATION OF TRYPTAMINE. PROPERTIES OF THE FORMALDEHYDE‐INDUCED FLUOROPHORES OF TRYPTAMINE AND RELATED INDOLE COMPOUNDS IN MODELS
Authors: BJÖRKLUND ANDERS , FALCK BENGT , HÅKANSON ROLF
Published: December 2008

A sensitive histochemical fluorescence procedure for the demonstration of tryptamine by a formaldehyde condensation reaction has been devised. This gives a 13–18 fold increase in the fluorescence yield of tryptamine compared with the conventional Falck‐Hillarp method. The conditions of the conventional formaldehyde condensation reaction were modified in the following two ways:

1. A gaseous oxidant (ozone) was introduced into the reaction vessel. Up to a certain concentration of ozone, the yield of the formaldehyde‐induced tryptamine fluorescence was markedly increased, probably because of an increased oxidative dehydrogenation of the initial condensation product. None of the other compounds tested showed such an increase in the fluorescence yield upon the combined formaldehyde‐ozone procedure. In fact, the fluorescence yields of catecholamines and 5‐HT were reduced to about 20 % compared with the yields in the conventional formaldehyde treatment. This decrease in the fluorescence intensity was presumably caused by an oxidative break‐down of the amines or of their fluorophores.

2. The amine models were acidified by means of HC1‐vapour or glacial acetic acid after the conventional formaldehyde treatment, causing a marked increase in the fluorescence yield of tryptamine.

The microspectrofluorimetric characteristics of the fluorophores of different indole compounds (tryptamine, N‐methyl tryptamine, 5‐HT, and tryptophan) where studied at various pH both after conventional formaldehyde treatment and after combined formaldehyde‐ozone treatment. The behaviour of the tryptamine fluorophore under various conditions was characteristic and differed from that of the other indoles and catechols tested, which makes possible the microspectrofluorimetric identification of tissue tryptamine.

The combined formaldehyde‐ozone reaction and the acidification after the formaldehyde reaction have been successfully applied to tissues incubated with tryptamine, and they provide sensitive and almost selective methods for the detection of tryptamine at the cellular level.
Stimulation of Gastric Acid Secretion by Irrigation of the Antrum with Some Aliphatic Alcohols1
Authors: Elwin Carl‐Eric
Published: December 2008

Ethyl alcohol is known to stimulate gastric acid secretion in fundic pouch dogs during irrigation of the antrum. A comparison was made with regard to such an effect of a series of aliphatic alcohols including methyl, ethyl, n‐propyl, isopropyl, n‐butyl, isobutyl, sec‐butyl and tert‐butyl alcohol. Dogs provided with a Heidenhain or a Pavlov pouch and isolated, innervated antral pouch were used. The only alcohol besides ethanol that showed a potent stimulatory effect was n‐propyl alcohol. All other alcohols tested had an effect less than half of that of ethanol. A change from one stimulatory alcohol to the corresponding isocompound caused a marked decrease of the effect. Isopropyl alcohol, one of the “non‐stimulatory” aliphatic alcohols, did neither show a synergistic nor an inhibitory action on the effect of ethyl alcohol or n‐propyl alcohol during simultaneous administration, indicating almost no interference with gastrin release mechanisms. n‐Propyl alcohol together with ethyl alcohol showed a dose‐response related action. Methyl alcohol was almost inactive. The results indicate that the stimulatory effect of alcohols could not be related to water or fat solubility but to the molecular configuration.
The Effect of Nerve Stimulation on Catecholamines Taken up in Adrenergic Nerves after Reserpine Pretreatment
Authors: Häggendal Jan , Malmfors Torbjörn
Published: December 2008

The effect of sympathetic nerve stimulation on the catecholamines (noradrenaline and dopamine) taken up and accumulated after i.v. administration was studied in the adrenergic nerves of rat iris with the fluorescence method and in the salivary glands with biochemical estimations after treatment with reserpine and a monoamine oxidase inhibitor. After administration of noradrenaline (0.1 mg/kg) the stimulation did neither cause a functional response in form of increased pupil diameter or bulb protrusion on the stimulation side, nor any decrease in the amount of noradrenaline accumulated in the examined organs on the same side. However, after administration of dopamine (1.0 mg/kg) there were clearcut functional responses on the stimulated side and a marked decrease of the levels of noradrenaline formed from dopamine. These results imply that exogenous noradrenaline cannot enter the proper sites for release by nerve impulses, 16 hrs after reserpine treatment, but that noradrenaline formed from exogenous dopamine in the doses used and after inhibition of monoamine oxidase can be released by nerve impulses in spite of reserpine pretreatment.
Relation of Afferent Nerve Excitability to Impulse Generation in the Frog Spindle
Authors: Ottoson D. , Shepherd G. M.
Published: December 2008

The excitability properties of the sensory nerve and its finer branches in muscle spindle have been studied in isolated preparations using electrical stimulation of the nerve in conjunction with controlled extension of the spindle. Characteristic differences in recovery cycle were demonstrated between the trunk fibre and the intracapsular branches. The excitability of the afferent nerve was modified by stretch; during stretching there was a rise in excitability and a shortening of the recovery cycle in direct relation to the amount of stretch. These changes were related to the underlying receptor potential and to local currents in the nerve. In the aftermath of stretch the excitability of the nerve as tested with electrical shocks was raised This was in contrast to the depression in mechanical sensitivity as revealed by a test stretch. When an extra impulse was elicited by an electrical shock in the course of sustained stretch the succeeding spike train was shifted, its general pattern being unchanged. It appears that the interjected spike transiently wipes out the currents leading up to the generation of the succeeding spike and resets the impulse generating process. Considerations of the functional properties of the afferent fibre and its branches as found in the present study suggest that the sensory system of the muscle spindle acts in synchrony during stretch.
The Sympathetic Innervation of the Oviduct in the Rat
Authors: Brundin J. , Fredricsson B. , Norberg K.‐A. , Swedin G.
Published: December 2008

The adrenergic innervation of the rat oviduct was studied by fluorescence microscopy. The outer half of the circular muscle layer was penetrated by a thin net of adrenergic nerve terminals throughout the isthmus. Adrenergic nerve terminals were scarcely seen in the muscular wall of the ampulla. In the mesotubarium close to the oviduct a dense net of adrenergic nerve terminals were observed. The functional role of the observations is discussed.
Effects of Reserpine on the Noradrenaline Content of Atrophied Rat Salivary Glands
Authors: Jonason Jan
Published: December 2008

The noradrenaline content was determined in intact and atrophied rat salivary glands at different time intervals after reserpine treatment, both with and without previous monoamine oxidase inhibition. After reserpine administration there was no significant difference between the two glands in the rate of noradrenaline disappearance. The loss of noradrenaline was somewhat accelerated in rats given dry wheat starch (a procedure which has been shown to increase the impulse flow of the adrenergic nerves to the salivary glands), showing that the impulse flow in the adrenergic nerves influences the noradrenaline reduction. After monoamine oxidase inhibition reserpine produced a much slower noradrenaline reduction rate. After this treatment a slower decrease was observed in the atrophied glands than in the intact ones. The data in this study indicate that most of the noradrenaline after reserpine treatment is metabolized by means of intraneuronally localized monoamine oxidase.
Afferent and Efferent Influences on the Activity Pattern of Single Olfactory Neurons
Authors: Døving Kjell B. , Hyvärinen Juhani
Published: December 2008

Single‐unit activity was recorded from secondary olfactory neurons in the burbot (Lota lotaL.) with either microelectrodes from the cell soma in the bulb or from single fibers in the olfactory tract. Stimulation of the olfactory epithelium on the contra‐ or ipsilateral side was made with glutamic acid, morpholin, and taurin, with both the efferent system intact and with the efferent activity to the bulb blocked by cutting or cooling the olfactory tract. Statistical time‐series analyses of the impulse sequences were performed in all experimental conditions. The interval histograms obtained were highly skewed. The histograms of the fiber recordings were often bimodal, whereas in the microelectrode recordings several exponential histograms were found. The intensity functions in two‐thirds of the fiber recordings showed rhythmical time dependent oscillations in the firing probability. These oscillations seemed to be of peripheral origin. The activity from the microelectrode recordings usually revealed renewal processes. Comparisons of the different experimental conditions showed a great variety of influences of peripheral stimuli and efferent activity on the activity patterns of the secondary neurons. Most frequently the differences between different experimental conditions of one cell were smaller than the differences between cells. Therefore, it does not seem likely that differences in external conditions would be coded as variations in the time structure of the impulse sequence.
Studies on the Effect of Adrenergic Blocking Drugs on Catecholamine‐Induced Platelet Aggregation and Uptake of Noradrenaline and 5‐Hydroxytryptamine
Authors: Bygdeman S. , Johnsen Ø.
Published: December 2008

Adrenaline (A) and noradrenaline (NA) were both found to induce platelet aggregation in citrated platelet rich human plasma, adrenaline being about 8 times more effective than noradrenaline. No effect was obtained with isoproterenol. The aggregating effect of catecholamines was stereospecific, the l‐form of NA being 30 times as effective as the d‐form. Platelet aggregation induced by A and NA could be blocked by phentolamine, phenoxybenzamine and dibenamine in the concentrations 10‐6M, 10‐4M and 10‐4M respectively, as well as with some β‐receptor blocking agents, pronethalol and propranolol, although only in a 10‐3M concentration. Almost no effect was observed with MJ 1999. High concentrations (10‐3M) of both α‐ and (β‐receptor blocking agents could block adenosine disphosphate induced aggregation indicating an unspecific effect of the blockers at this concentration. Uptake of3H‐NA and14C‐5‐HT in the platelets was inhibited by both α‐ and β‐receptor blocking agents in concentrations from about 10‐5M. There was no obvious correlation between inhibition of uptake by α‐receptor blocking agents and their effect on catecholamine‐induced aggregation indicating that uptake of A or NA was not a necessary step in catecholamine mediated platelet aggregation.
Increased Vascular Permeability Caused by the Trypsin‐like Enzymes Purified from Rat Submandibular Gland
Authors: Ekfors T. O. , Hopus‐Havu V. K. , Malmiharju T.
Published: December 2008

The vascular permeability increasing effect of several trypsin‐like enzymes purified from the rat submandibular gland was studied. The size of the lesion caused by an intradermal injection of small amounts of the enzymes in blued rabbits was used as the measure of the permeability increasing effect. Salivain and four isozymic forms of a kallikrein‐like peptidase caused a very marked increase in the vascular permeability. A clearly weaker response was obtained with glandulain and Depot‐Padutin®, and a very weak response with trypsin. These lesions as well as that caused by bradykinin could not be prevented by prometazine, as was the lesion caused by histamine. The response to the enzymes was lowered to about one half by prior injections of phenylbutazone. It was concluded that the enzymes effect the vascular permeability by liberating vasoactive kinins.
Circulatory and Respiratory Effects of Different Doses of Prostaglandin E1in Man
Authors: Carlson Lars A. , Ekelund Lars‐Göran , Orö Lars
Published: December 2008

Prostaglandin E1(PGE1) was infused i.v. into 8 healthy male subjects in doses from 0.032 to 0.58 μg/kg/min. With doses from 0.058 to 0.10 μg/kg/min a hyperkinetic circulation was induced, characterized by an increase in heart rate and stroke volume, decrease in peripheral resistance, and a decrease in AVO2difference and simultaneously a less pronounced increase in O2uptake. At the higher dose levels there was a further increase in heart rate and decrease in brachial artery pressure. The stroke volume decreased but the cardiac output remained above resting levels. The high doses also produced an alveolar hyperventilation, a further increase in O2consumption and in three cases a respiratory alkalosis.
A Technique for Repeated Renal Clearance Measurements in Undisturbed Rats
Authors: Engberg Anders
Published: December 2008

A technique for simultaneous i.v. infusion into and blood and urine sampling from relatively unrestrained rats. Detailed description of the design of catheters, of their implantation and of sampling procedures. Control autopsy results are discussed.
Hypothalamic Control of Adrenergic Outflow to the Stomach in the Cat
Authors: Jansson G. , Lisander B. , Martinson J.
Published: December 2008

Experiments were performed on chloralosed, adrenalectomized cats with recording of gastric volume, blood pressure and skeletal muscle blood flow. The vagal nerves were cut, but the vagal excitatory fibres to the stomach could be activated by electric stimulation. Topical stimulation of the hypothalamic defence area, or surrounding “pressor” areas, produced not only the characteristic known circulatory responses, but also a prompt and often complete inhibition of a vagally induced increase of gastric motility.‐But when the stomach was not under the influence of continuous vagal excitatory activity, corresponding stimulation of the hypothalamus rarely had any effect on gastric volume, and then only an insignificant and sluggish increase despite considerable “myogenic” tone of the stomach. Stimulation of the adjacent hypothalamic sympatho‐inhibitory area, on the other hand, augmented the vagally induced gastric motility and thereby suggested the presence of a centrally induced suppression of a prevailing sympathetic inhibitory influence on the stomach.‐All the above mentioned effects on gastric volume, produced by central nervous stimulation, could be blocked by guanethidine in these vagotomized cats. It is concluded that the hypothalamus contains neural mechanisms, which can affect stomach motility by changing in both directions the impulse frequency in the inhibitory adrenergic outflow to this organ. Simultaneous activity of vagal excitatory fibres to the stomach was found to be a prerequisite for reducing significantly gastric motility and tone when the adrenergic fibres were excited. This is compatible with the hypothesis that the adrenergic fibres exert their inhibitory effect mainly, or only, by acting on the parasympathetic ganglionic cells, which mediate the vagal excitatory influence to the gastric smooth muscles.
The Effects of L‐Triiodothyronine on the Self‐Selected Circadian Rhythm of Rest and Activity in the Canary
Authors: Wahlström Göran
Published: December 2008

Canaries were used as experimental animals. The birds were kept singly. Each cage was separately illuminated. The light could be extinguished by the bird if it used one perch in the cage. As darkness corresponds to rest in adapted birds the self‐selected circadian rhythm of rest and activity could be recorded. The waking‐up times were used as the starting point of the circadian period. L‐triiodothyronine (T3) was given as a single dose at different times during the activity. Oral doses up to 10 mg/kg given early in the activity did not influence the length of the circadian period. There was an uncertain increase in activity. Similar doses given late in the activity increased the length of the circadian period. The duration of activity was increased and the rest was decreased. The changes were maximal in the period after the one in which T3 was given and gradually disappeared during approximately a week. The effects on the circadian period seemed to be related to the amount of T3 given, in the dose interval used (1–10 mg/kg). The increase in activity was less influenced by the amount of T3. Parenteral administration of 1 mg/kg T3 late in the activity caused changes corresponding to those induced by 6–8 mg/kg orally. The magnitude of the maximal increase in duration of circadian period and activity was independent of the pre‐experimental value. Thyrotropic hormone (1–2 IU) in a few birds caused a small increase in the duration of the circadian period in which it was given.
The Evolution of Vascular Smooth Muscle Responses to Histamine and 5‐Hydroxytryptamine
Authors: Reite Ola Bodvar
Published: December 2008

In an attempt to trace the phylogenetical origin of stimulatory (constrictive) and inhibitory (dilatatory) actions of histamine and 5‐hydroxytryptamine on mammalian vascular smooth muscle, the vascular responses to these drugs were studied in jawless vertebrates and fish. Effects were recorded as blood pressure changes in dorsal and ventral aorta after intravascular administration of drugs, and as resistance changes in artificially perfused branchial and systemic blood vessels after administration into the perfusion circuit. The reliability of experimental procedure and recording technique was tested by observing the presence of responses to adrenaline, noradrenaline or acetylcholine. Pharmacological blocking agents were used to dissociate between specific and unspecific actions. In jawless vertebrates, the vascular effects of histamine and 5‐hydroxytryptamine seemed to reflect unspecific actions on adrenergic receptor mechanisms. The effects in cartilaginous fish were slight. Characteristic effects, produced by specific stimulatory actions on vascular smooth muscle, appeared in higher bony fish. Inhibitory actions were not revealed in any species. By comparing the results obtained in intact animals with those from perfused preparations, it may be concluded that stimulatory actions of 5‐hydroxytryptamine appear as a constrictor response in the branchial blood vessels of teleosts, while the stimulatory actions of both histamine and 5‐hydroxytryptamine are fully developed and produce vasoconstriction in all studied sections of the vascular system in lungfish.
Influence of Chloride Ions and ATP‐Mg++ on the Release of Catecholamines from Isolated Adrenal Medullary Granules
Authors: Lishajko F.
Published: December 2008

Carlsson et al. (1963) and Kirshner (1962) have shown that ATP‐Mg stimulates uptake of amines in isolated adrenal medullary granules. This finding has been confirmed (Lishajko 1968) and in addition it was shown that ATP‐Mg inhibits the “spontaneous” release of amines when phosphate buffer was used as medium. On the other hand Oka et al. (1966), Poisner and Trifaro (1967) have reported that ATP‐Mg in certain incubation media increases the release rate of catecholamines in isolated chromaffin granules.

In the present communication it will be shown that the releasing effect of ATP‐Mg is dependent on the presence of chloride ions in the medium.
The Action of Tetrodotoxin on the Frog's Isolated Muscle Spindle
Authors: Albuquerque E. X. , Chung S. H. , Ottoson D.
Published: December 2008

Tetrodotoxin in concentrations of 0.8–1.0 × 10‐7g/ml completely blocked conducted activity of the afferent nerve of isolated frog muscle spindle without affecting the receptor potential. Development of block was characterized by an increase in threshold of the nerve, a gradual delay of the onset of the impulse response and a reduction and decomposition of the individual action potentials into smaller spikes. The spike decomposition appeared to be due to a de‐synchronization of the conducted activity in the branched afferent terminals. After block by tetrodotoxin for up to 20 min the normal response could be restored by washing the preparation with Ringer's solution. The blocking action of tetrodotoxin was delayed and reduced by increasing calcium; removal of calcium had the opposite effect. Tetrodotoxin (1000 ng/ml) had no significant effect on the receptor potential. With low sodium plus tetrodotoxin the receptor potential was reduced by about 50 %; this reduction was reversed by addition of normal sodium. It is suggested that the sodium carrying system of the generator potential differs from that underlying the regenerative activity.
Ion Movements in Red Cells Treated with Propranolol
Authors: Ekman Aarne , Manninen Vesa , Salminen Simo
Published: December 2008

Addition of propranolol to a suspension of human red cells was found to cause outflow of K+ ions and, to a lesser degree, inflow of Na+ ions, until a new stationary state was reached in which their cell/medium concentration ratios did not deviate much from unity. The cell volume decreased. Lactic acid production increased slightly. Against the outflow of bulk K+ ions, tracer K+ and Rb+ ions accumulated very rapidly in the cells and then began to flow out. The ratio of inward to outward rate constant of K+ tracer immediately decreased, while that of Na+ tracer increased, transiently exceeding the medium/cell concentration ratio of Br‐ tracer, in which no abrupt change occurred. In the propranolol‐induced stationary state the cationic tracer rate constants were higher than in the untreated cell, but not so high as just after addition of propranolol. Their order was K.+ > Rb+ > Cs+ > Li+ > Na+. It is suggested that an accelerated “carrier”‐mediated exchange diffusion of cations across the cell membrane, driven by the flow of bulk ions down their gradients, would explain the rapid tracer ion movements.
The Refractory Time in the Visual Cortex of Albino Guinea‐Pigs1
Authors: Simonsen Svend E.
Published: December 2008

The absolutely refractory time of the summed cortical response, tested with paired supramaximal stimuli to the contralateral optic nerve of chloralose‐anesthetized guinea‐pigs, was 86±3 msec. The absolutely unresponsive time tested with paired white flashes to the contralateral eye was 96±6 msec. The difference was thought to be due to the fact that the flashes were not quite supramaximal; in one experiment the absolutely irresponsive time was reached by increasing the intensity of the light and then the recovery time was the same whether the paired stimuli were shocks to the optic nerve or flashes. The colored flashes used –Λmax 450 mμ, 510 mμ and 590 mμ‐evoked responses of equal size and latency and with the same unresponsive time, 125 msec±3 msec. A late response to flashes was variable; when it was large, it could engulf the primary response to the testing flash and make the determination of the unresponsive time impossible.
Relationship between Blood Pressure and Diameter of Ascending Aorta in Normal and Hypertensive Rabbits
Authors: Aars Harald
Published: December 2008

Earlier studies of strips from rabbit aorta suggest that hypertensive resetting of aortic baro‐receptor activity (Aars 1968a) might be due to hypertensive changes of the aortic wall in the receptor area (Aars 1968b). In order to obtain information under conditions equal to the demonstration of resetting, the relationship between blood pressure and diameter of ascending aorta has been examined in 11 normal rabbits and five rabbits with renal hypertension of about one week's duration. The transit time of ultrasonic pulses between two crystals glued to aorta was used to measure the aortic diameter. Below 70–100 mm Hg, aortic distensibility was equal in hypertensive and normal rabbits. The normal aorta became markedly stiffer at higher pressures, whereas in hypertensive rabbits the relationship between pressure and diameter remained linear to near hypertensive control pressures. This indicates that at pressures below approximately 130 mm Hg, stretching of aortic wall elements‐and presumably stimulus to baroreceptor activity‐was less in hypertensive than in normal animals. The curves for dynamic elastic modulus were also shifted to higher pressures, illustrating the ability of the aortic wall to maintain almost the same distensibility at control pressures in hypertensive and normotensive conditions. The rate of change of pulsatory diameter variations was closely related to their amplitude, and this relationship did not differ significantly in normal and hypertensive rabbits.
Studies on the Distribution and Elimination of [3H8] Pyridoxine in Mice
Authors: Dahlkvist Giesela , Lindstedt Sven , Tiselius Hans‐Göran
Published: December 2008

[3H8] Pyridoxine has been administered by i.v. injection to mice, and the concentration of isotope has been determined in different tissues up to 30 days after the administration. An initial high uptake was found in all tissues except brain. The concentration decreased rapidly during the first day after administration and then at a slow rate. The decrease of isotope concentration was more rapid in liver than in muscle or carcass. The elimination of the vitamin from the body reservoir was estimated to be 7.9 per cent per day from day 1 to 30 compared to 6.5 per cent per day as calculated from the rate of excretion of isotope in the urine. One week after the administration of the isotope the concentration was approximately the same in heart, skeletal muscle, brain and kidney, and 20 % higher in liver. Between day 7 and 30 after the administration [3H8] pyridoxine 75% of the recovered isotope was found in carcass, 10–15% in liver and the remainder in other tissues.
Electrical Stimulation of a Human Ventrolateral‐Subventrolateral Thalamic Target Area
Authors: Johansson Gunnar G.
Published: December 2008

A method is described for electrical stimulation of human subcortical brain structures. The necessity is shown for monitoring both the voltage across and also the current through the stimulated brain tissue, as well as the duration of the stimuli applied. Stimulus trains of constant composition were repeatedly applied to a ventrolateral‐subventrolateral thalamic target area in 12 alert patients undergoing stereotaxic thalamotomy. Stimulation at the clinical threshold resulted in motor and “sensory” responses projected to contralateral parts of the body. In spite of small temporary variations, no distinct change of response from one stimulus train to the next in the same patient could be detected when the stimulation was applied at intervals of either 15, 30, or 60 sec. The current thresholds, on the other hand, showed a tendency to decrease if the intervals were less than 60 sec. The stimulation method and the results of stimulation are discussed.
Electrical Stimulation of a Human Ventrolateral‐Subventrolateral Thalamic Target Area
Authors: Johansson Gunnar G.
Published: December 2008

A ventrolateral‐subventrolateral thalamic target area was electrically stimulated in connection with stereotaxic neurosurgery in 16 alert patients with Parkinson's disease, in 4 patients with hereditary intention tremor and in 1 patient with choreoathetosis. The stimulations were performed as a part of a larger investigation concerned with the effect of altering stimulus parameters on the clinical responses evoked. Unidirectional square wave pulses with a constant pulse duration and repetition frequencies ranging from 1 to 200 pulses per second were applied. The stimulation was kept at the threshold for clinical responses by balancing the different repetition frequencies with the peak current. The stimulation elicited motor and “sensory” responses. The character of the responses depended on the pulse repetition frequency used. The projected localization of the responses in the body remained unchanged. The peak current‐pulse repetition frequency relationship at the threshold for evoking clinical responses is shown. The results are discussed.