bluuebunny/crossref_metadata_2025 huggingface dataset:
Noradrenaline Uptake and Fluorescence Histochemistry in Bovine Splenic Nerves
Authors: Hamberger Bertil , Malmfors Torbjörn , Stjärne Lennart
Published: December 2008

A combination of fluorescence histochemical and radiometric methods was used to study the uptake and accumulation of exogenous noradrenaline in the non‐terminal sympathetic axons of isolated bovine splenic nerve trunk. Non‐incubated nerve fibers mostly showed a low fluores cence intensity, but a few fibres exhibited very strong fluorescence with a beaded appearance. The number of beaded axons could be increased by incubation, especially with a‐methyl‐nor‐adrenaline. After incubation, even in amine‐free media, fluorescent material accumulated near the cut ends and also close to areas accidently compressed during the preparation. The results suggest that transport of noradrenaline had occurred under the experimental conditions. In cubation with noradrenaline, particularly after inhibition of monoamine oxidase, or with a‐methyl‐noradrendine, resulted in a strong concentration‐dependent increase of the fluores cence intensity, even in the presence of reserpine. Under the experimental conditions the tissue/ medium ratio was found to be about 60, using 10‐6M racemic3H‐noradrenaline in the in cubation medium. It is concluded that the sons of the bovine splenic nerve trunk possess a reserpine‐resistant mechanism for concentrating noradrenaline which is qualitatively similar to, but quantitatively considerably less efficient than, that previously observed in nerve terminals in other tissues and species.
Oxygen Deficit and Muscle Metabolites in Intermittent Exercise
Authors: Karlsson J. , Saltin B.
Published: December 2008

Muscle ATP, CP, ADP, glycogen, G‐6‐P. lactate, and blood lactate concentration were studied in three subjects during intermittent exercise. One min of extremely heavy bicycle work was followed by five min of rest, which was repeated five times. Oxygen uptake was determined continuously and oxygen deficit could be calculated for each activity burst. Oxygen uptake was also measured during the first 60 min of recovery following the last exercise period. The accumulated oxygen deficit increased with each work period. The ratio between oxygen deficit and oxygen debt was 0.55.

The breakdown of ATP and CP stores showed progressive phosphagen depletion with each burst of activity while the muscle lactate concentration reached its highest level, ca 23 mmoles × kg‐1 wet muscle, as early as after the first work period. Blood lactate increased gradually during the first 15–20 min of interval periods and then reached a level of 20 mmoles × l‐l. Muscle glycogen concentration was reduced with each work period but did not become completely depleted in any of the subjects. The subjects were as exhausted after the first work period as after the last one. Of the studied metabolic variables muscle lactate concentration was then the one best related to the point of exhaustion.
Lactate in Working Muscles after Prolonged Exercice
Authors: Karlsson Jan
Published: December 2008

Nearly normal muscle lactate concentrations were obtained with a submaximal work load preceded by prolonged heavy exercise for 2–4 and 5–7 hrs, resulting in a marked decrease in muscle glycogen content. The same was true if prolonged work for 2–4 hrs preceded a standardized supramaximal work test in contrast to prolonged work for 5–7 hrs. In all these studies, however, the blood lactate concentration was reduced after prolonged work, thus con firming earlier findings (Astrand et al. 1963). This might indicate enhanced utilization of blood‐borne lactate induced by the preceding, prolonged work.
Spatial Distribution of Receptor‐Responses to Stimulation with Different Odours
Authors: Mustaparta Hanna
Published: December 2008

The olfactory receptor‐responses recorded from the enzinentia olfactoria in the frog were studied to find whether receptors with different specificities were homogeneously or non‐homogeneously distributed. Receptor potentials (EOGs) were recorded simultaneously from two different areas of the eminentia olfuctoria. 21 different substances were used; 8 of these substances belonged to a homologous serie of cycloketones. For each substance the ratio N between the two EOG‐amplitudes was measured. N‐values obtained with the recording electrodes kept at fixed positions were found to vary for different odours and for different concentrations of the same odour. By recording with one electrode at different distances from the other fixed electrode N‐values for different areas were obtained for each odour. The N‐values showed an increase for some odours and a decrease for others. These observations indicate a non‐homogeneous distribution of receptors with different specificities. For the cycloketones, at the concentrations used, only small variations were found in N‐values at all positions tested. Keeping one electrode fixed and placing the other stepwise away in a posterior or lateral direction, a successive general reduction in N‐values for all the substances was found. This suggests a general reduction in receptor density in posterior and lateral direction.

I would like to thank Dr. Kjell Døving for suggesting the topic, and for his constant en couragement during the work.

The cycloketones were kindly provided by International Flavor & Flagrances, Holland.
Persistence of Cerebral Blood Flow Autoregulation Following Chronic Bilateral Cervical Sympathectomy in the Monkey
Authors: Eklöf B. , Ingvah D. H. , Kågström E. , Olin T.
Published: December 2008

The cerebral blood flow was measured in 11 monkeys after step changes in arterial blood pres sure in the pressure range 30–140 mmHg. In one group of 5 animals a bilateral excision of the superior cervical ganglia was performed about 2 weeks prior to the experiment. These animals, as well as those with an intact sympathetic innervation of the cerebral vessels, demonstrated an almost constant rCBF at pressures above 50–60 mmHg,2.e. both groups showed autoregulation. It is concluded that cervical sympathectomy does not abolish autoregulation of the cerebral blood flow.
Influence of Changes in Microcirculation on the Excitability of the Sensory Unit in the Tooth of the Cat
Authors: Edwall Lennart , Jr Donald Scott
Published: December 2008

Simultaneous determinations of radioactive iodide disappearance rate (k‐value) and sensory nerve impulse frequency from dentinal cavities were performed on canine teeth of anesthetized cats. Changes in k‐value reflecting changes in pulpal microcirculation were obtained by direct sympathetic nerve stimulation or by thermal stimulation. Sympathetic nerve stimulation re duced the k‐value and induced an initial increase in nerve impulse frequency. During maximal sympathetic nerve stimulation this initial increase was followed by a marked depression in impulse frequency. Application of heat increased k‐value as well as impulse frequency, while cold reduced k‐value and induced an initial increase in nerve impulse frequency followed by a decrease. Thermal stimulation superimposed during maximal sympathetic stimulation, when k‐value was depressed, was inadequate to evoke an appreciable increase in sensory nerve in pulse frequency. It is suggested that the excitability of sensory units in the tooth is strongly modulated by changes in pulpal microcirculation induced by, for example, stimulation of sympathetic vasoconstrictor fibres.
Regulation of the CSF pH in Acute and Sustained Respiratory Acidosis
Authors: Messeter Kenneth , Siesjö Bo K.
Published: December 2008

In order to study the regulation of the cerebrospinal fluid pH during hypercapnia, plasma and CSF acid‐base parameters were measured in rats exposed to about 11% CO2 for periods varying from 5 min to 5 days. When combined with previously measured CSF‐plasma d.c. potential differences, the plasma and CSF pH values and bicarbonate concentrations could be used to calculate electrochemical potential differences (δμ) for H+ and HCO3‐ between CSF and plasma. Hypercapnia lead to a 20 mEq/kg increase in the CSF bicarbonate concentration, most of which occurred during the first 24 h. There was a somewhat larger [HCO3‐] increase in the CSF than in plasma water but in none of the compartments did the pH normalize. In acute hypercapnia (5–180 min) the calculated δμH+ and δμHCO3 values changed in a direction which would favor influx of HCO3‐a into the CSF. In the sustained groups (24–120h) the δμ's were close to the normocapnic control values. Since the accumulation of bicarbonate in the CSF occurred at a time when there was a suitable “passive” diffusion gradient, and since the CSF [HCO3‐] in the chronic state was upheld without a significant change in the δμ's, it is concluded that the regulation of the CSF pH in hypercapnia does not seem to require active transport of H+ or HCO3‐.
Modification of Kaolin‐Induced Intracranial Hypertension at Various Time‐Periods after Superior Cervical Sympathectomy in Rabbits
Authors: Edvinsson L. , Owman Ch. , West K. A.
Published: December 2008

The intracranial pressure measured as the ventricular fluid pressure (VFP) was recorded continuously via a cannula in the left lateral ventricle of the brain of conscious rabbits 2 days after intracisternal administration of kaolin, known to induce intracranial hypertension. The effect of sympathectomy was studied at various time‐periods after bilateral removal of the superior cervical ganglia: (a) During a 2‐day recording period following shortly after sympathectomy the VFP of kaolin‐treated animals was considerably lower compared to non‐sympathectomized, kaolin‐treated animals, (b) One week after sympathectomy the VFP was initially lower than in the non‐sympathectomized controls. However, it rapidly increased to very high levels, and all animals died within 10 hours after the recording was started, (c) About 2 weeks after sympathectomy the pressure tended to be lower than in the non‐sympathectomized control animals. It is suggested that these findings are mainly the result of changes in the intracranial blood volume (although direct effects of the sympathectomy on cerebrospinal fluid circulation can not be excluded). Thus, shortly after sympathectomy–period (a)–when the transmitter is leaking from the degenerating nerves, the intracranial vessels contract and the blood volume decreases. In addition, the intracranial hypertension has probably resulted in a compensatory increase in cerebrospinal fluid absorption and/or reduction in its formation, which will further lower the VFP. Period (b): the denervated vessels dilate and the increased intracranial blood volume will add to the intracranial hypertension caused by the blocked cerebrospinal fluid circulation and the edema produced by the implantation of the pressure cannula. Period (c): the brain vessels have developed a pronounced denervation supersensitivity to circulating catecholamines, the vascular tone is enhanced and the reduced blood volume will tend to lower the VFP.
The Influence of Noradrenaline Synthesis Inhibition on the Disposition of3H‐Metaraminol in Peripheral Adrenergic Nerves
Authors: Almgren Olle
Published: December 2008

The disappearance of dl‐metaraminol‐7‐3H (3H‐MA) from intact and decentralized rat salivary glands and from rat hearts after an i.v. injection of 40 μg/kg of the amine was studied. One group of rats received 500 mg/kg i.p. of an inhibitor of noradrenaline synthesis, α‐methyltyrosine methylester (H 44/68), 1 h before the amine injection and thereafter repeated injections every 12 h. The rats not treated with the synthesis inhibitor served as controls. The initial phase of the normally two‐phasic exponential disappearance of3H‐MA from intact glands was markedly retarded by H 44/68 treatment. Also the3H‐MA disappearance from the decentralized glands was retarded by H 44/68 treatment, while the disappearance from the heart was not significantly affected. It is suggested that3H‐MA is undergoing continuous displacement from storage sites by newly synthesized transmitter. After H 44/68 treatment such displacement no longer occurs.
Effect of Amphotericin B on the Frog Skin in vitro. Evidence for Outward Active Potassium Transport across the Epithelium
Authors: Nielsen Robert
Published: December 2008

It is shown that amphotericin B (5×10‐5 M) increases the permeability of the frog skin to potassium, chloride and urea. The potassium flux was more strongly increased from the inside to the outside than from the outside to the inside of the skin, whereas the chloride and the urea fluxes were equally enhanced in both directions. The increased potassium flux from the inside to the outside could not be explained by a potassium loss from the cells. It is suggested that a part of the high outward potassium flux was due to an active outwards transport of potassium.
Release of Noradrenaline from the Dog Heart In Situ after Intravenous and Intracoronary Administration of 5‐Hydroxytryptamine
Authors: Pillion Gilles M. B. , Lluch Salvador , Uvnäs Börje
Published: December 2008

The following experiments have been carried out in order to establish the validity of the hypothesis that the cardiac stimulatory effects of 5‐hydroxytryptamine (5‐HT) are mediated by catecholamines. Release of cardiac noradrenaline (NA) has been observed after administration of 5‐HT either intravenously or intracoronarily. After labelling the heart with3H‐5‐HT, it was possible to release this amine by cardioaccelerator nerve stimulation even after treatment with an adrenergic β blocker. It is concluded that the cardiac stimulatory effects of 5‐HT are mediated by NA; this NA is mainly derived from sympathetic nerve endings by intra‐neuronal exchange for 5‐HT.
The Role of the Adrenal Medulla in Posthemorrhagic Pulmonary Hypertension
Authors: Bø G. , Hognestad J.
Published: December 2008

A marked increase in pulmonary vascular resistance (PVR) is known to develop in cats during hemorrhagic hypotension. The present investigation is an attempt to evaluate the role played by adrenal catecholamines in this posthemorrhagic PVR‐development. Anesthetized cats with open chests and on positive pressure ventilation were used. Six animals in which the adrenals had been acutely denervated were bled until the mean arterial pressure was 50 mm Hg. This level of hypotension was maintained for 3 h by further bleedings and/or small retransfusions. Cats similarly treated received catecholamines continuously infused (5 μg/kg/min) during the hemorrhagic period. Adrenaline alone, noradrenaline alone, or a 1:4 mixture of the two catecholamines were used. Comparisons were carried out between these animals and animals similarly bled but with intact adrenal innervation.

In the cats with denervated adrenals the posthemorrhagic rise in PVR was low as compared with the high level seen in animals with intact adrenals. The gradual fall in the number of circulating thrombocytes was also significantly less in the denervated group than in the control group. Infusions of catecholamines to animals with denervated adrenals caused pulmonary hypertension in the hemorrhagic period. These findings indicate that catecholamines released from the adrenals play an important role in the development of the posthemorrhagic pulmonary hypertension previously described.
Comparison of the Effects of Prostaglandins E1, E2and F2αon the Sympathetically Stimulated Rabbit Heart
Authors: Hedqvist Per , Wennmalm ÅKe
Published: December 2008

PGE1, PGE2and PGF2αin concentrations ranging from 3×10‐9M to 1.5 × 10‐6M were infused into the isolated perfused, sympathetically innervated rabbit heart in order to assess their capacity to inhibit the chronotropic, inotropic and noradrenaline overflow responses to sympathetic nerve stimulation, as well as the chronotropic and inotropic responses to infusion of noradrenaline. The coronary flow was increased by PGE1but not by PGE2of PGF2α. The three compounds did not change the heart rate or the contractile force, indicating that the reported increase in heart rate after i.v. infusion of PGE1or PGE2is reflex in origin. PGE1and PGE2inhibited the outflow of noradrenaline as well as the chronotropic and inotropic responses to nerve stimulation in a dose‐dependent way, while PGF2αwas ineffective. None of the compounds altered the chronotropic or inotropic response to exogenous noradrenaline. It is concluded that PGE1and PGE2but not PGF2α, inhibit the sympathetic neurotransmission in the rabbit heart, and that they do this mainly by reducing the release of the transmitter from the adrenergic nerve terminals.
Uptake of Serotonin in Blood Platelets in vitro. II: Further Studies on the Effects of Small Anions
Authors: Lingjærde O.
Published: December 2008

According to previous reports, serotonin (5HT) uptake in human blood plateletsin vitrorequires the presence of chloride. Chloride can be replaced by other small univalent, but unphysiological anions, such as (in decreasing order of effectiveness) bromide, nitrite, iodide, nitrate, and formate, However, the effect of nitrite, especially, is kinetically different from that of chloride. Whereas the effect of chloride obeys simple Michaelis‐Menten type kinetics, increasing concentrations of nitrite give a sigmoidal 5HT uptake curve. Moreover, the effects of nitrite and chloride are partly additive. It is suggested that these effects of nitrite can be explained by assuming that nitrite, besides being able to replace chloride in the so‐called “anionic site” of the carrier, also has an effect on a hypothetical “activating site”. This simple model cannot, however, easily explain all the complex interactions between chloride and nitrite. It is also reported that preincubation with different anions affects the uptake rate to very varying degrees, and that the anions have somewhat different effects on spontaneous 5HT outflux.
Choroid Plexus Uptake of Atropine and Methylatropine in vitro1
Authors: Eriksson K.‐H. , Winbladh B.
Published: December 2008

Rabbit choroid plexa in vitro accumulate tritium labelled atropine and methylatropine by a mechanism which fulfils the conventional criteria for active transport. The two drugs seem to share the same carrier with other tertiary and quaternary amines investigated, i.e. morphine, promethazine, choline, hexa‐and decamethonium. The ratios for telencephalic choroid plexus tissue: medium were 10 for atropine and 65 for methylatropine at an incubation medium concentration of 10‐4 M. Maximal velocity of uptake was in the order of 0.35 mmol/kg × min for atropine and 0.26 mmol/kg × min for methylatropine while apparent Km was 0.9 mM and 0.08 mM respectively. The results are discussed in relation to other reports of choroid plexus transport mechanisms and their possible physiological meaning.
The Effect of Acute and Chronic Hypercapnia upon the Lactate, Pyruvate, α‐ketoglutarate, Glutamate and Phosphocreatine Contents of the Rat Brain
Authors: Messeter Kenneth , Siesjö Bo K.
Published: December 2008

The influence of hypercapnia upon the tissue contents of lactate, pyruvate, α‐ketoglutarate, glutamate and phosphocreatine was studied in rats exposed to about 11 % CO2 for 15 and 45 min, and for 3, 24, 48 and 72 h, respectively. Acute hypercapnia (15 and 45 min) was associated with highly significant decreases in the lactate, pyruvate, α‐ketoglutarate, glutamate and phosphocreatine contents. In sustained hypercapnia (3 h and onwards), the lactate, pyruvate and α‐ketoglutarate contents were partially restored but phosphocreatine and glutamate remained decreased. In acute hypercapnia the intracellular lactate/pyruvate ratio was increased, but it returned to normal in sustained hypercapnia (> 24 h). The results suggest that the intracellular lactate/pyruvate ratio is affected both by changes in the intracellular pH and by changes in the NADH/NAD+ ratio.
Chemical Composition of Basophil Granules from Isolated Rat Mast Cells
Authors: Bergqvist Ulla , Samuelsson Gunnar , Uvnäs Börje
Published: December 2008

A protein fraction was isolated from rat mast cell granules. Disc gel electrophoresis and peptide mapping showed this fraction to be a mixture of 1 or 2 main components and 2–3 minor components. On ultracentrifugation the protein fraction behaved as an homogeneous material with a molecular weight of 5600. Amino acid analysis showed the presence of all the common amino acids (with the possible exception of tryptophan). High contents of lysine, aspartic acid, glutamic acid, proline, glycine and valine were noted. The content of cysteine was remarkably low. The isoelectric point of the main component(s) was found to be around 9.
The Hemodynamic Consequences of Regional Hypotension in Spontaneously Hypertensive and Normotensive Rats
Authors: Folkow Björn , Gurévigh Moisie , Hallbäck Margareta , Lundgren Yen , Weiss Lilian
Published: December 2008

In 3 week old spontaneously hypertensive rats (SHR) and normotensive control rats (NCR) the aorta was ligated distally to the renal arteries, lowering the blood pressure in the hindquarters some 30–50 per cent compared with “ordinary” NCR or SHR. 6–16 weeks later the hindquarters of an ordinary NCR were perfused simultaneously with those of an aorta‐ligated NCR or SHR in 20 paired experiments at constant flow with an oxygenated plasma substitute, from maximal dilatation to maximal constriction as induced by graded noradrenaline (NA) doses. Constructed “resistance curves” of the aorta‐ligated NCR and SHR hindquarters showed a 40–50 % decreased resistance at maximal dilatation with almost proportional decreases of the steepness of the dose‐response curve and of the maximal pressor response, when compared with ordinary NCR, while the threshold sensitivity to NA was the same as in unligated shamoperated NCR. The difference from unligated SHR was still more striking, yielding three separate sets of “resistance curves” each related to the pressure level present in the hindquarters during the months prior to the perfusion. The results indicate an adaptive structural change of the resistance vessels in the chronically hypotensive hindquarters with a media reduction and considerably increased vascular lumina. Thus, the elimination of the pressure load seems capable of completely preventing the development of the adaptive media increase that otherwise seems to occur in SHR. An altered pressure load, decreased or increased, evidently affects the design of the resistance vessels rapidly and this, in turn, will greatly contribute to the hemodynamic differences characterizing hypo‐ and hypertension as compared to normotension.
3H‐Noradrenaline Release and Mechanical Response in the Field Stimulated Mouse Vas Deferens
Authors: Farnebo Lars‐Ove , Malmfors Torbjörn
Published: December 2008

Isolated mouse vas deferens was preincubated with3H‐noradrenaline (3H‐NA) and then mounted in a small glass chamber where it was superfused with buffer and stimulated by an electrical field. Tritium overflow into the buffer and mechanical activity was followed.

Almost all the radioactivity taken up and retained in the vas deferens, and about 75 % of the tritium overflow during stimulation was due to3H‐NA. Stimulation for 30 sec at 4–16 Hz caused a biphasic contraction of the vas deferens with an initial rapid twitch and a second tetanus‐like phase of contraction. The stimulation‐induced tritium overflow during stimulation at 16 Hz for 30 sec was 1.8 %(i.e.1.8 % of the total tritium content of the vas deferens was overflowing in response to stimulation). The fraction of the tritium content of the vas deferens overflowingperimpulse at different frequencies of stimulation was the same at 1–16 Hz and was around 3.5 xlO“5. Upon stimulation for various time periods (10–120 sec) the stimulation‐induced overflow was found to be proportional to time. The mechanical response, on the other hand, decreased upon prolonged stimulation.

No contractions were elicited in vas deferens from mice pretreated with 6‐OH‐dopamine. Atropine did not affect the response to stimulation. No contraction and no stimulation‐induced overflow was obtained when tetrodotoxin was added to the superfusing buffer. Inhibition of neuronal uptake of NA by desipramine potentiated the contraction caused by stimulation, but the stimulation‐induced overflow was almost unchanged. The a‐receptor blocking drugs phentolamine and phenoxybenzamine decreased the second phase of contraction and increased the stimulation‐induced overflow. Papaverine inhibited the contraction and increased the stimulation‐induced overflow. Stimulation of a‐receptors by methoxamine potentiated the contraction and decreased the stimulation‐induced overflow.

From the drug‐experiments it is concluded that a decreased effector response is accompanied by an increased3H‐NA release, while an increased effector response is accompanied by a decreased3H‐NA release. The results indicate the existence of a transsynaptic regulatory mechanism for NA release.
Synthesis of Noradrenaline in Isolated Rat Iris during Field Stimulation
Authors: Farnebo Lars‐Ove , Lidbrink Peter
Published: December 2008

Isolated rat irides from untreated rats or rats pretreated with the tyrosine hydroxylase inhibitor H44/68 or the dopamine‐β‐hydroxylase inhibitor FLA63 were incubated in physiologic buffer for 30 min and then superfused by buffer for 60 min in small chambers. Some of the irides were stimulated by an electrical field at 10 Hz for 60 min. Endogenous NA was enzymatically determined or the irides were examined with the fluorescence histochemical method of Falck and Hillarp. Irides that were not stimulated contained about 5 ng noradrenaline (NA) per iris. Stimulation reduced the NA content of irides from untreated or FLA63 pretreated rats to about 60%of the unstimulated control. Stimulation caused an altered distribution of NA with a less pronounced cumulation of NA to the varicosities of the adrenergic nerve terminals. Addition of tyrosine to the superfusing buffer did not diminish the stimulation‐induced decrease of NA. In irides from rats pretreated with H44/68, stimulation reduced the NA content to about 25%of the unstimulated control. A great reduction of the fluorescence intensity of the majority of the nerve terminals was observed. The difference found in stimulation‐induced depletion of endogenous NA between irides of untreated and H44/68 pretreated rats is most likely due to synthesis of NAin vitroin the irides of untreated rats.
Drug‐Induced Changes in the Release of3H‐Monoamines from Field Stimulated Rat Brain Slices
Authors: Farnebo Lars‐Ove , Hamberger Bertil
Published: December 2008

Rat cerebral cortex slices preincubated with3H‐noradrenaline (NA) or3H‐5‐hydroxy‐tryptamine (5‐HT) and neostriatal slices preincubated with3H‐dopamine (DA) were stimulated by an electrical field and the overflow of radioactivity determined. The effect of drugs on overflow and release from central NA, DA and 5‐HT nerve terminals was studied. Inhibition of monoamine uptake with desipramine, cocaine or chlorimipramine increases the stimulation‐induced overflow and the results indicate that at least 35%of the released monoamines may be taken up again into the monoamine nerve terminals. Activation of NA, DA and 5‐HT receptors with clonidine, apomorphine and LSD‐25 respectively seems to decrease transmitter release. Blockade of NA and DA receptors with neuroleptic drugs increases the stimulation‐induced overflow, probably due to an increased release from the NA and DA nerve terminals. It is known that drugs used in the present investigation have a nerve impulse dependent influence on the rate of synthesis and turnover of monoamines in the central nervous system, which is generally considered to be secondary to changes in nerve impulse frequencyviaanervousfeed‐back mechanism. However, it seems probable from the present results that the turnover changes foundin vivoafter these drugs may at least partly also be due to alocaleffect at the central monoamine synapse, possiblyviaa negative feed‐back mechanism.
Relationships between Force and Velocity of Shortening in Rabbit Papillary Muscle
Authors: Edman K. A. P. , Nilsson E.
Published: December 2008

The instantaneous relationship between isotonic load and velocity of shortening was studied in rabbit papillary muscles using a quick‐release technique which involved critical damping of the lever. The force‐velocity curve was determined from the experimental data by means of the least squares method using a computer program. The curve exhibited a true hyperbolic shape and virtually the same values of the constantsaandbin Hill's equation were obtained when the analysis was carried out during the rising or falling phase of an isometric contraction. The experimental basis of the discrepant results reported in previous studies has been scrutinized. Variability in active state intensity and contractile element length between individual force‐velocity determinations may account for the non‐hyperbolic shape of the force‐velocity curve obtained in an analysis of after loaded contractions. Quick releases performedwithoutcritical damping of the lever movements were found to have a depressant effect upon the myocardial activity resulting in a distortion of the force‐velocity curve at intermediate and small loads. The distortion of the curve was more pronounced when the analysis was carried out during relaxation than during the rising phase of the contraction. The deactivating effect is most likely attributable to the rapid fluctuations in speed of shortening of the contractile unit caused by inertial oscillations of the lever system after an underdamped quick‐release.
Effects of Hypoxia and Glucocorticoids on the Histochemically Demonstrable Catecholamines of the Newborn Rat Carotid Body
Authors: Hervonen Antti , Kanerva Lasse , Korkala Olli , Partanen Seppo
Published: December 2008

The histochemically demonstrable catecholamines of newborn rat carotid bodies were studied using the formaldehyde induced fluorescence (FIF) method. The effects of both heavy anoxia and repeated injections by glucocorticoids were registered. The newborn rat carotid body consisted of bright yellow fluorescing cells. During the following 2 weeks the intensity of this fluorescence decreased distinctly while fluorescent network of adrenergic nerve fibres developed. The fluorescent nerves were in close contact with the chief cells of the carotid body. Hydro‐cortisone or prednisolone treatment prevented the loss of fluorescence normally occurring. Anoxia caused a marked decrease in the FIF in the majority of glomus cells in 9—16 day old rats.
Effect of 6‐Hydroxydopamine on the Ganglion Cells and the Small Intensely Fluorescent Cells in the Superior Cervical Ganglion of the Rat
Authors: Eränkö Liisa , Eränkö Olavi
Published: December 2008

Newborn rats were injected daily for 8 days with 6‐hydroxydopamine, (6‐OH‐DA) 50 mg/kg b. w. Disappearance of over 90 % of the ganglion cells from the superior cervical ganglion and the coeliac ganglion was observed 3 weeks after discontinuation of the injections. The surviving ganglion cells were larger than normal and exhibited less intense than normal catecholamine fluorescence but showed normal or slightly decreased activity of acetylcholinesterase and nonspecific cholinesterase. Electron microscopically, hypertrophy of the endoplasmic reticulum and the Golgi apparatus were observed. 6‐OH‐DA caused, besides destruction of ganglion cells, an increase in the relative number of the small intensely fluorescent cells. However, this increase was due to loss of ganglion cells from between the small cells, and the total number of small intensely fluorescent cells counted from complete series of sections through the ganglia was the same in controls as that in animals injected with 6‐OH‐DA. It is concluded that the small intensely fluorescent cells are resistant to chemical sympathectomy, and differ in this respect from ordinary ganglion cells.
Effect of Hydrocortisone on Histochemically Demonstrable Catecholamines in the Sympathetic Ganglia and Extra‐adrenal Chromaffin Tissue of the Rat
Authors: Eränkö Liisa , Eränkö Olavi
Published: December 2008

Hydrocortisone acetate was administered intraperitoneally to newborn rats daily for 5 days, 40 mg/kg b.w. They were killed on the 6th day. Adult rats were given the same dose daily for 14 days and killed on the 16th day. Catecholamines were demonstrated by formaldehyde vapour induced fluorescence. In the 6‐day‐old rats treated with hydrocortisone there was a distinct increase in the size of the extra‐adrenal chromaffin bodies, in the number of fluorescent cells in them and in the intensity of the fluorescence of these cells, as compared with the controls. Hydrocortisone treatment also caused about a tenfold increase in the number of the small intensely fluorescent (SIF) cells in the superior cervical ganglion, the coeliac ganglion and the lumbar prevertebral ganglia of the young rats. The newly formed SIF cells were scattered single or in clusters of a few cells throughout the ganglia, including sites in which no SIF cells were normally present before hydrocortisone treatment. In the adult rats, hydrocortisone did not cause any dramatic changes in the sympathetic ganglia. The SIF cells were present in clusters in the same way as in the control ganglia but there was a tendency towards an increase in the number of SIF cells in the clusters. It is concluded that hydrocortisone causes in young rats a greatly increased formation of the SIF cells from poorly differentiated, weakly fluorescent stem cells, while proliferation of already existent SIF cells is less pronounced.
General Characteristics of Sympathetic Activity in Human Skin Nerves
Authors: Hagbarth K.‐E. , Hallin R. G. , Hongell A. , Torebjörk H. E. , Wallin B. G.
Published: December 2008

Synchronized bursts of efferent sympathetic impulses, appearing either spontaneously or triggered by various peripheral stimuli, were recorded with microelectrodes inserted percutaneously into skin nerve fascicles in alert, adult subjects. The signals were abolished by sympathetic ganglion blocking agents and by Lidocaine nerve blocks proximal to the recording site. Many of the sympathetic discharges were succeeded by skin resistance changes and plethysmographic vasoconstrictor responses within the innervation zone of the fascicle impaled. The sympathetic activity was not pulse synchronous as in muscle nerves and the spontaneous sympathetic volleys occurred largely independently of spontaneous blood pressure variations, indicating a relative lack of baroreflex control of the vasoconstrictor outflow to the skin. A loose coupling was observed, however, between the resting respiratory rhythm and the spontaneous sympathetic bursts in the skin nerves.
Manoeuvres Affecting Sympathetic Outflow in Human Skin Nerves
Authors: Delius W. , Hagbarth K.‐E. , Hongell A. , Wallin B. G.
Published: December 2008

Sympathetic activity was recorded from human skin nerves during the execution of a variety of different manoeuvres. The neural activity (composed of vasoconstrictor and sudomotor impulses) was regularly affected by emotional, thermal and respiratory stimuli. Mental stress, body cooling and increased respiratory movements all increased the sympathetic outflow, whereas the activity decreased during moderate body warming and when the. subject was calm and relaxed. Manoeuvres known to cause changes in baroreceptor activity usually did not affect the sympathetic outflow to the skin. When comparing neural and effector organ responses during the different manoeuvres the changes in sympathetic activity correlated well with changes in skin vascular resistance (either measured simultaneously or as reported in the literature). A comparison of the sympathetic responses recorded from human skin‐ and muscle nerves was also made. It was concluded that most manoeuvres had different effects in the two nerve types, thereby confirming earlier indirect evidence for selective regional control of the sympathetic outflow.
Reflex Relaxation of the Stomach Elicited from Receptors Located in the Heart. An Analysis of the Receptors and Afferents Involved.
Authors: Abrahamsson Hasse , Thoren Peter
Published: December 2008

In cats anesthetized with chloralose electrical afferent stimulation of the right cardiac nerve promptly elicited marked hypotension, bradycardia and relaxation of the stomach. Stimulation threshold and conduction velocity measurements indicated that the stimulated afferents were unmyelinated fibres. The circulatory and gastric responses were abolished by cervical vagal blockade on the stimulation side. Administration of nicotine intrapericardially or veratrum alkaloids i.v. produced similar circulatory and gastric responses as the electrical nerve stimulation. The effects of veratrum were markedly reduced upon application of a local anesthetic in the pericardial cavity. Reflex gastric relaxation was also elicited in response to occlusion of the ascending aorta or mechanical stimulation of the left ventricle. With occlusion of the pulmonary artery only slight gastric responses were obtained during the occlusion. Pronounced gastric responses were recorded upon occlusion of a coronary artery, the effect being abolished by section of the vagi in the neck. – It is concluded that marked reflex relaxation of the stomach can be elicited from heart receptors, probably located in the left ventricle and with unmyelinated afferents in the vagi. It is suggested that the described reflex gastric response may form part of a vomiting pattern.
Postnatal Development of the Mechanical Response of the Isolated Rat Vas Deferens to Nerve Stimulation
Authors: Swedin Göran
Published: December 2008

Isolated vas deferens preparations from rats aged 2–22 days were stimulated transmurally in a superfusion bath. The first responses to postganglionic nerve stimulation appeared in preparations from animals 3 days of age whereas responses to exogenous noradrenaline (NA) and direct stimulation of the smooth muscle cells were obtained one day earlier. Preparations of all ages responded readily to low concentrations of exogenous NA (0.2–5.0, μg/ml) while acetylcholine (ACh) had to be added in much higher concentrations (10–100, μg/ml) to give equal direct responses.

a‐receptor blockers (phentolamine or phenoxybenzamine, 0.2–2.0, μg/ml) totally inhibited the contractions of preparations from animals up to about 10 days of age, but thereafter the effect was changed into potentiation of the responses. Atropine (0.5–2.0, μg/ml) generally caused a slight decrease of contractions of preparations up to about 15 days of age, but at later stages it was without effect.

It is concluded that the major part of the motor innervation of the rat vas deferens is adrenergic but that subtreshold amounts of ACh probably are liberated from some source within the organ on transmural stimulation. The most probable explanation for the greater sensitivity of the young vas deferens preparations to the specific receptor blockers seem to be a greater accessibility of the junctional receptors, perhaps in combination with relatively smaller amounts of transmitter liberated at these early ages.
Changes in Precapillary Resistance in Skeletal Muscle Vessels Studied by Intravital Microscopy
Authors: Eriksson E. , Lisander B.
Published: December 2008

Eriksson, E. and B. Lisander.Changes in precapillary resistance in skeletal muscle vessels studied by intravital microscopy.Acta physiol. scand. 1972.84.295– 305.

The microcirculation of the cat's tenuissimus muscle was observed with particular regard to internal arterial diameters, linear flow rates and capillary flow distribution. Simultaneous recordings of systemic arterial blood pressure and blood flow in this and adjacent muscles were carried out. The effects of graded vasoconstrictor fibre stimulation or of intra‐arterial vasodilator drug administration could be directly studied in this muscle region. Although causing a slight blood flow increase, acute sympathetic denervation was not followed by any sustained diameter increase in the microvessels studied. Morphologically clearcut precapillary sphincters were not observed and during “rest” the denervated precapillary vessels displayed a fairly steady tone. Nevertheless, capillary flow patterns changed perpetually. Capillary contents were stagnant and flow even reversed sometimes due to transient trapping of passing leucocytes. Maximal drug‐induced dilations caused 50 % diameter increases in arteries of 15–100μ,with smaller changes in larger ones. Intense vasoconstrictor fibre activation lowered flow 6–8 times and reduced diameters in arteries of 15–200μwith a maximum at the 30μsize, where closure could occur. Luminal reductions were absent in immediate precapillary sections. During stimulation a marked leucocytosis was observed in the microvessels. It is concluded that in the muscle studied, lacking morphologicallly distinct precapillary sphincters, variations in capillary blood flow and in the perfused capillary surface area are brought about by luminal changes of end‐arterioles, to which white cell obstruction of microvessels may contribute. Further, the relative importance of the resistance of the different series‐coupled sections may vary considerably with the regional tone. Sections responsible for changes in resistance and in capillary flow distribution are evidently not distinctly separated morphologically.
The Oxygen Supply to the Retina, II. Effects of High Intraocular Pressure and of Increased Arterial Carbon Dioxide Tension on Uveal and Retinal Blood Flow in Cats
Authors: Alm Albert , Bill Anders
Published: December 2008

Alm, A. and A. Bill.The oxygen supply to the retina, II. Effects of high intraocular pressure and of increased arterial carbon dioxide tension on uveal and retinal blood flow in cats. A study with radioactively labelled microspheres including flow determinations in brain and some other tissues.Acta physiol. scand. 1972.84.306–319.

15μand 35μmicrospheres labelled with8SSr and169Yb were used to determine the rate of blood flow through various intraocular tissues, optic nerve, brain, kidney cortex and small intestine in cats at normal and increased Paco2‐ One eye had its spontaneous intraocular pressure, the other eye had its pressure stabilized at a higher level. At normal Paco2 a reduction in perfusion pressure resulted in decreased vascular resistance in the iris, the ciliary body and the retina, but not in the choroid. In the retina the eye with reduced perfusion pressure had a significantly higher blood flow than the control eye. Increased PaCO2resulted in increased blood flow in all ocular tissues and all extraocular tissues studied except the kidney cortex. Reductions in perfusion pressure at high Paco2resulted in further decreases in vascular resistance in two eyes of seven only.

The results suggest that about 21 % of the O2consumed by the retina is delivered by the retinal blood vessels, the rest by the choroid. Both myogenic and metabolic mechanisms seem to contribute to the adjustment of retinal vascular resistance after a change in perfusion pressure.
The Effect of Slight Hypothermia on Liver Function as Measured by the Elimination Rate of Ethanol, the Hepatic Uptake and Excretion of Indocyanine Green and Bile Formation
Authors: Krarup Niels , AnkerLarsen Jens
Published: December 2008

Krarup, N. and J. A. Larsen.The effect of slight hypothermia on liver function as measured by the elimination rate of ethanol, the hepatic uptake and excretion of Indocyanine Green and bile formation.Acta physiol. scand. 1972.84.396–407.

Liver function was followed by determination of the elimination rate of ethanol, bile flow, the hepatic uptake and excretion of Indocyanine Green and the excretion of bile acids and electrolytes. A fall in the body temperature 1–2oC from normal, was accompanied by a sudden decrease in the elimination rate of ethanol, bile flow and the hepatic uptake and excretion of Indocyanine Green of about 25 per cent. The effect of cooling on bile flow and the elimination rate of ethanol were significantly correlated. The cooling caused only minor effects on the excretion of bile acids and the biliary electrolyte composition. The findings may be explained by intrahepatic vascular changes resulting in a decrease in the number of perfused sinusoids and a corresponding reduction in the functional capacity.
Effect of Increased Afterload on the Inotropic State and Uptake of Free Fatty Acids in the Intact Dog Heart
Authors: Kjekshus J. , Mjøs O. D.
Published: December 2008

Kjekshus, J. and O. D. Mjøs.Effect of increased afterload on the inotropic state and uptake of free fatty acids in the intact dog heart.Acta physiol. scand. 1972.84.415–427.

In anesthetized dogs treated with atropine and pentolinium tartrate–a ganglionic blocking agent–the possibility was tested that release of myocardial catecholamines contributes to the regulation of cardiac output during increased outflow resistance. When left ventricular systolic pressure was raised by an average of 100 mm Hg (from 99 to 193 mm Hg), cardiac output increased (+34 %) from 122 to 163 ml/min kg and maximum rate of rise of left ventricular pressure (dP/dt) (+ 50%) from 1.30 to 1.80 mm Hg 10‐3/s. Myocardial uptake of free fatty acids (FFA) showed an average increase of 221%(from 2.9 to 9.3 μEq/min 100 g), in spite of unchanged arterial FFA concentrations, indicating adrenergic activation of the heart. These responses were abolished following a similar rise in left ventricular systolic pressure (from 88 to 184 mm Hg) in reserpine‐treated dogs during ganglionic blockade. Changes in left ventricular end‐diastolic pressure, as well as myocardial oxygen consumption, were similar in both groups. The present study supports the conclusion that catecholamines are released from myocardial stores during augmented intraventricular pressure, thereby explaining the increase in cardiac output. However, in the catecholamine‐depleted heart, cardiac output is maintained by the Frank‐Starling mechanism alone.
Uptake of3H‐cortisol by Rabbit Polymorphonuclear Leukocytes in vitro
Authors: Simonsson Bengt
Published: December 2008

Rabbit pseudoeosinophilic polymorphonuclear leukocytesin vitrohave an uptake of3H‐cortisol, which is partly saturable and partly non‐saturable. The saturable component was much more dependent on temperature during accumulation and washout than the non‐saturable component. The metabolic inhibitors N‐ethyl maleimide, p‐chloro‐mercuribenzene sulfonic acid, iodoacetic acid and 2,4‐dinitro‐phenol and preheating at 67° C significantly decreased the saturable uptake while the non‐saturable uptake, if anything, was increased in some experiments. Dinitro‐phenol slightly accelerated the washout of the saturable component.

The characteristics of the saturable3H‐cortisol uptake strengthens the evidence that it corresponds to a specific interaction with a receptor in the rabbit pseudoeosinophilic polymorphonuclear leukocytes, since it behaves like the specific hormone uptake in other tissues under similar conditions. The non‐saturable uptake behaves like a non‐specific uptake.
Concentration of Noradrenaline in Pial Vessels, Choroid Plexus, and Iris during Two Weeks after Sympathetic Ganglionectomy or Decentralization
Authors: Edvinsson L. , Owman Ch. , Rosengren E. , West K. A.
Published: December 2008

Changes in the noradrenaline concentration of the sympathetically innervated pial vessels, choroid plexuses, and irides of the rabbit were measured fluorometrically at various periods during the first 2 weeks after pre‐ or postganglionic denemation (decentralization or excision of the superior cervical ganglia). The noradrenaline values fell to negligible amounts within 2 days after ganglionectomy in all organs, probably somewhat slower in choroid plexuses. After decentralization the noradrenaline level increased in the pial vessels, whereas in the choroid plexuses and iris it initially decreased followed by normalization. The fall occurred somewhat later in the iris. It is suggested that the results of the denervation experiments reflects the presence of functionally different types of sympathetic neurons in one and the same ganglion.