bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sympathetic Control of Rhythmically Active Vascular Smooth Muscle as Studied by a Nerve‐muscle Preparation of Portal Vein
Authors: Johansson Börje , Ljung Bengt 
Published: December 2008

AbstractTechniques are described for recording directly the contractile responses elicited in the longitudinal smooth muscle of cat or rabbit portal vein by vasomotor nerve stimulation in situ or in vitro. This vascular smooth muscle, which shows a spontaneous rhythmic activity of 3 to 8 contractions per minute, responded to splanchnic or postganglionic nerve stimulation by an increase in the mean level of tension associated with an increased frequency of contractions. Guanethidine abolished these neurogenic responses indicating that they were due to adrenergic sympathetic fibre activation. Effects of vagal nerve stimulation were weak and inconsistent. The quantitative tension responses produced by splanchnic or postganglionic nerve stimulation at graded impulse rates increased steeply in the low frequency range and reached a maximum at 8 to 16 imp/sec. These frequency‐response curves, obtained by direct recording of vascular smooth muscle contractions, are in conformity with those found in previous investigations studying blood flow or regional blood volume in intact vascular beds. The mechanisms by which the sympathetic innervation controls activity in rhythmically active vascular smooth muscle and the quantitative aspects of this influence are discussed in the light of the present results
Effects of Catecholamines on Pulmonary Blood Volume
Authors: Hauge A. , Lunde P. K. M. , Waaler B. A. 
Published: December 2008

AbstractThe effect of arterially injected adrenaline and noradrenaline on lung blood volume has been examined in isolated, blood‐perfused lung preparations from rabbit and cat. Both substances caused rapid and relatively marked reductions in the weight of the preparations, which was followed continuously. This weight reduction is interpreted as being due to constriction of capacitance vessels. This effect on the capacitance vessels was mediated via α‐receptors, as addition of the α‐inhibitor phentolamine abolished the response. Addition of the β‐inhibitor propranolol did not interfere with the effect of the catecholamines on the capacitance vessels. Noradrenaline usually gave an increase, adrenaline usually a decrease in pulmonary vascular resistance in this preparation. The effect of the catecholamines on capacitance vessels was dissociated from the effects of these drugs on the vascular resistance in the organ.
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

AbstractDorsal 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

AbstractIn 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

AbstractA 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

AbstractIn 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

AbstractPosition 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

AbstractPosition 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

AbstractGastrin 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

AbstractMucosal 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

Abstract 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

AbstractIt 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

AbstractThe 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

AbstractThe 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

AbstractProtamine 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

AbstractAn 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

AbstractThe 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

SummaryIt 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.