bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibitory Processes in Gustation
Authors: Hellekant Göran
Published: December 2008

Different salt and acid solutions were applied in pairs with a short intervening water rinse to the tongue of the cat while the summated chorda tympani nerve response was recorded. It was observed that the first exposure usually depressed the response to the following one. The magnitude of the depression varied and depended on the solutions used. In general K2SO4 and Li2SO4 caused the strongest depression, while MgCl2 and NaCl were most depressed. However, no substance was entirely inert in affecting the response to the second stimulus or was always unaffected by being the second. The results were discussed and subjected to comparison with earlier results. They were interpreted as being influenced by at least three different mechanisms.
Oxygen Toxicity in Nitrogen Mixtures
Authors: Almqvist H. , Jr. M. Arborelus , Barr P. O. , Jansson B. , Kaijser L.
Published: December 2008

3 groups of 20 mice were exposed to 4 atmospheres oxygen partial pressure with pure oxygen or nitrogen mixtures, containing 63 or 45% oxygen. The time was measured for the first 10 oxygen fits and for 50% of the animals to become unconscious. With both parameters, if anything, nitrogen seemed to decrease the sensivity of the mice for oxygen poisoning. Provided interspecies differences do not exist, this would imply that decompression‐free diving down to 23 m would be possible. The reasons are discussed for failures in earlier trials to decrease nitrogen partial pressure by adding oxygen to the breathing medium during diving.
Some Studies on the Mechanism by which d‐Amphetamine Antagonizes Guanethidine Induced Adrenergic Neurone Blockade
Authors: Obianwu Hopé O.
Published: December 2008

Electrical stimulation of the sympathetic trunk elicited contraction of rat lower eyelid. This response was greatly reduced or abolished by guanethidine (15–25 mg/kg, s.c.) within 30–40 min. Infusion of d‐amphetamine, 0.5 mg/kg, greatly antagonized the blockade within 30–60 min. Amphetamine similarly administered to control animals potentiated the response of the eyelid to nerve stimulation and tyramine. After inhibition of MAO, amphetamine still enhanced the response to tyramine and nerve stimulation. Potentiation of the response to nerve stimulation did not appear to be due to inhibition of reuptake process since this effect was still observed after protriptyline treatment, a substance which is about twenty times as active as amphetamine in this respect. It is suggested that the ability of amphetamine to potentiate the response to nerve stimulation may be an important factor in its antagonism of guanethidine‐induced nerve blockade.
Formation of Extracellular Adenosine Triphosphate by Tumour Cells
Authors: ÅGren Gunnar , Ronquist Gunnar
Published: December 2008

The formation of extracellular ATP by Ehrlich ascites tumour cells and HeLa cells was studied. The tumour cells were incubated with the substrates, including 32P‐labelled inorganic phosphate, and cofactors of the glyceraldehyd‐3‐phosphate dehydrogenase and phosphoglycerate kinase reactions (complete system), as well as with an incomplete system lacking ADP, NAD+ and glyceraldehyde‐3‐phosphoric acid. All incubations were performed under isotonic conditions. After 1 min incubation of tumour cells, an 8‐fold increase in the 32P‐labelled ATP took place with the complete system, compared with the incomplete system. All the (32P)ATP formed as a consequence of the presence of the phosphorylated substrates and cofactors in the complete system could be recovered in the extracellular medium. No measurable leakage of intracellular (32P)ATP into the extracellular medium occurred. The extracellular medium did not contain significant amounts of solubilized enzymes responsible for the extracellular formation of (32P)ATP. The presence of intact tumour cells during incubation was necessary for the main part of (32P)ATP to be formed. It is therefore concluded that most of the (32P)ATP present in the extracellular medium was formed by enzymes located on the surface of the tumour cells.
The Effects of Extracellularly Applied ATP and Related Compounds on Electrical and Mechanical Activity of the Smooth Muscle Taenia Coli from the Guinea‐Pig
Authors: Axelsson Johann , Holmberg Bo
Published: December 2008

The effect of external ATP and related compounds on the electrical and mechanical activity of isolated pieces of taenia coli has been studied. ATP, AMP and adenosine caused a decrease in the spontaneous tone, a decrease in the frequency of spike discharge, and hyperpolarization. ATP was up to 100 times as potent an inhibitor of spontaneous activity as AMP or adenosine. GMP, guanosine and inosine had no effect. High K+ contractures were relaxed by the same compounds and adenine, which was the most potent. Here again GMP, guanosine and inosine had no effect. ATP, AMP and adenosine prevented or shortened the initial depolarization produced by acetylcholine and carbachol. Inorganic phosphate was liberated from ATP and AMP applied to the bathing solution. The hydrolysis was not significantly decreased by g‐strophanthin. p‐Hydroxy‐mercuribenzoate caused an initial excitation as well as g‐strophanthin but neither inhibited the relaxing effect of ATP. The effects of extracellularly applied ATP are consistent with the view that they are exerted through changes in membrane permeabilities and that some of these effects are brought about by the adenosine part of the molecule.
Blockade of the PhosphorylaseaActivating Effects of Catecholamines and Adenosine 3‘,5’‐Monophosphate (Cyclic AMP) in High K+ or Choline Buffer Media
Authors: Lundholm Lennart , Mohme‐Lundholm Ella , Vamos Nandor
Published: December 2008

In isolated rat diaphragm suspended in a buffer solution where Na+ had been exchanged for K+ or choline the basal phosphorylaseaactivity was reduced and the phosphorylaseaactivating effect of adrenaline and isoprenaline was blocked or reduced. The total phosphorylase activity and the level of high energy phosphate compounds were unchanged in high‐K+ buffer but the former reduced in choline buffer. The basal phosphorylaseaactivity was reduced in a Ca++‐free solution but the effect of adrenaline was unchanged. The phosphorylaseaactivating effect of the catecholamines is mediated by adenosine 3′,5′‐monophosphate (cyclic AMP). Addition of cyclic AMP to the buffer solution had a stimulating effect on the phosphorylaseaactivity of the rat diaphragm. This effect was blocked or reduced when Na+ in the buffer solution was exchanged for K+ or choline. It has been demonstrated that the stimulating effect of adrenaline on the cyclic AMP content in the diaphragm is unchanged in high‐K+ media. We suggest that the blockade of the phosphorylaseaactivating effect of the catecholamines in high‐K+ media was due to an inhibition of the action of cyclic AMP.
Resting Membrane Potential in Neck and Leg Muscles of Young Rats
Authors: Boëthius Jörgen
Published: December 2008

Earlier investigations on single muscle fibres of rat and chicken have shown that the muscle membrane potential increases during ontogeny (Fudel‐Osipova and Marty‐nenko 1962, Boëthius and Knutsson 1966). This finding prompted a further interest in membrane characteristics associated with development and initiated the present study on the time relations of membrane potential build‐up throughout the cephalocaudal axis.
The Effects of Hypercapnia and Hypocapnia upon the Cerebrospinal Fluid Lactate and Pyruvate Concentrations and upon the Lactate, Pyruvate, ATP, ADP, Phosphocreatine and Creatine Concentrations of Cat Brain Tissue
Authors: Granholm Lars , Siesjö Bo K.
Published: December 2008

The lactate and pyruvate concentrations in cisternal cerebrospinal fluid (CSF), and the lactate, pyruvate, ATP, ADP, phosphocreatine, and creatine concentrations in brain tissue were measured in cats during hyper‐ and hypocapnia. (PaCO2 10–100 mm Hg). Both the CSF and the tissue concentrations of lactate and pyruvate varied inversely with the arterial CO2 tension. In hypercapnia the tissue lactate/pyruvate ratio increased in accordance with a theoretical curve, calculated for a pH dependent equilibrium between the lactate/pyruvate and the NADH/NAD+ systems. In hypocapnia, however, there was no corresponding decrease in the CSF and tissue lactate/pyruvate ratios but a progressive increase at arterial CO2 tensions below 25–20 mm Hg. The inter‐pretation of these results, which indicate the presence of tissue hypoxia at such low CO2 tensions, were complicated by the presence of unchanged tissue levels of ATP and phosphocreatine. The results also showed that in hypocapnia, pyruvate, but not lactate, was distributed between the extra‐ and intracellular spaces according to the pH gradient, while in hypercapnia, lactate, but not pyruvate, had this distribution. The similarity of the changes in CSF and tissue lactate and pyruvate concentrations lend further support to the assumption that the CSF lactate/pyruvate system reflects cellular redox states.
Tubular Sodium Reabsorption and the Regulation of Renal Hemodynamics. The Effect of Chlorothiazide on Renal Vascular Resistance
Authors: Aperia Anita C.
Published: December 2008

In hydropenic dogs under Nembutal anesthesia chlorotiazide, in parallell with its inhibition of distal tubular Na reabsorption, caused a marked increase in renal vascular resistance and a decrease in total renal blood flow and glomerular filtration rate. The renal vasoconstriction appeared to be both pre‐ and post‐glomerular, since the glomerular filtration rate was reduced in proportion to the total renal blood flow. The vasoconstriction could not be abolished by sympathetic blockade (Dibenzylene). During ureteral obstruction, when formation of glomerular filtrate could be regarded as minimal despite of unimpaired renal blood flow, the vasoconstrictive response to chlorothiazide was much reduced. This excludes a direct constrictive effect of chlorothiazide on the renal vascular bed. The constrictive response of the renal vascular bed was found to be correlated with the inhibition of Na reabsorption rather than with increase in urine flow. The data are interpreted as supporting the hypothesis that Na transfer in the distal tubule is one important mechanism for controlling renal vascular tone. a control that may be mediated by the renin angiotensin system. It is further suggested that the important factor is the intracellular Na concentration in the first part of the distal tubule. lather than intratubular concentration as such at this site. Contrary to previous interpretation the present observations suggest that it is a decrease in Na transfer, rather than an increase, that is directly or indirectly involved.
Effects of Hyperosmolarity on the Volume of Vascular Smooth Muscle Cells and the Relation between Cell Volume and Muscle Activity
Authors: Arvill Anders , Johansson Börje , Jonsson Olof
Published: December 2008

Electrical and mechanical responses of vascular smooth muscle to variations in extracellular osmolarity were analysed in a previous study using isolated preparations of rat portal vein (Johansson and Jonsson 1968). The purpose of the present investigation has been to measure the changes in the volume of the cells of this smooth muscle when exposed to hyperosmolarity and to elucidate further the previously postulated relation between cell volume and muscle activity. Distribution of water, urea‐14C and sucrose‐14C in the isolated portal vein has been determined. Urea‐14C rapidly equilibrates in a volume of 77.9 ml/100 g wet tissue weight which agrees satisfactorily with the total water content of the muscle (79.0 ml/100 g). The smooth muscle cells thus show a high membrane permeability for urea. When the muscle is incubated in isoosmotic Krebs solution the distribution volume of sucrose‐14C reaches 45.4 ml/100 g within 15 min and then increases very slowly to 49.4 ml/100 g within 120 min. The former value has been taken to represent the extracellular space. After 20 min in a hyperosmotic medium (normal Krebs solution +150 mmoles sucrose/l) there is a decrease of total wet tissue weight to approximately 86 per cent of the control value and, simultaneously, a relative increase of extracellular space from 45.4 to 48.5 ml/100 g. Calculations show that the intracellular fluid volume has then decreased by about 34 per cent indicating an almost perfect osmotic behaviour of the smooth muscle cells in response to hyperosmolarity of this degree. The changes in muscle activity observed during and after exposure to hyperosmotic urea‐ and sucrose‐Krebs solutions are discussed in the light of the changes in cell volume and the time course of the uptake of urea‐14C and sucrose‐14C. The present results support the existence of a relation between cell volume and activity in vascular smooth muscle.
Modulating Effect of Prostaglandin E2 on Noradrenaline Release from the Isolated Cat Spleen
Authors: Hedqvist P.
Published: December 2008

Stimulation of the splenic sympathetic nerves in the dog and the cat has been shown to increase the outflow of prostaglandin from the spleen (Davies, Horton and Withrington 1967, Gilmore, Vane and Wyllie 1968). Recently prostaglandin E1 was found occasionally to reduce the release of noradrenaline (NA) caused by stimulation of the splenic nerves in the cat (Hedqvist and Brundin 1969).
Catechol‐O‐Methyltransferase in Autonomic and Sensory Ganglia of the Cat
Authors: Giacobini Ezio , Kerpel‐Fronius Sandor
Published: December 2008

Catechol‐o‐methyltransferase (COMT) activity was determined in normal and preganglionically denervated sympathetic ganglia as well as in parasympathetic and sensory ganglia of the cat by means of the micro‐radiochemical method of McCaman (1965). Low levels of COMT activity were found to be present in all three types of investigated ganglia. In the sympathetic ganglia the COMT activity was almost evenly distributed. No correlation could be demonstrated between COMT activity, monoamine oxidase (MAO) activity and the reported catecholamine content in the various sympathetic ganglia. Preganglionic denervation of sympathetic ganglia did not significantly change the enzyme activity. The results indicate that in the autonomic ganglia COMT is confined neither to presynaptic structures nor to “adrenergic” neurons.
Unit Responses in the Rat Cochlear Nucleus to Repetitive, Transient Sounds
Authors: Møsller Aage R.
Published: December 2008

The response patterns are described of cochlear nucleus units (termed rat transient units) which only responded to a tone burst with a single discharge evoked immediately after the onset. When these cells were stimulated with bursts of repetitive clicks such units showed a marked selectivity to the click repetition rate. At a low click repetition rate one discharge was evoked for each click but this one to one relationship failed rapidly when the click rate was increased slightly above a given click repetition rate. Any additional increase in click rate resulted in only a single discharge fired immediately after the onset of a click burst and thus resembling these units' response to tone bursts. By replacing the click sounds by short bursts of pure tones presented repetitively it was shown that rat transient units were not selective to repetition rate per se, but rather, to the duration of silent interval between successive sounds. The activity of these units to click stimulation could be inhibited by broad band noise or by pure tones within certain frequency limits. Furthermore, these units showed a spectral selectivity which appeared when the stimulation was pure tones or band‐pass filtered clicks. The spectral region of highest sensitivity varied among the individual units in the range from 5 to 20 kHz and was thus widely different from the critical repetition rate for click stimulation. The latter rate was found to vary from 200 to 800 clicks per second in different units.

These findings may thus explain why, in psychoacoustic experiments, repetitive presentation of short sounds results in a pitch perception which is dependent on the length of the silent period between successive sounds.
An Electromyographic Analysis of Muscular Activity in the Hindlimb of the Cat during Unrestrained Locomotion
Authors: Engberg I. , Lundberg A.
Published: December 2008

During walking in unrestrained cats the electromyographic activity in many hindlimb muscles has been correlated with the angular movement in the hip, knee and ankle joints. The activity is rather uniform in the extensors but individual in different functional groups of flexor muscles. Observations on the precise timing of the onset of the main extensor activity suggest that it is not a reflex effect produced by stimulation of receptors (from muscle or skin) in the limb. It is assumed that the basic activity is a centrally programmed alternating activation of extensors and flexors. A possible reflex regulation mainly from la afferents of this basic activity is discussed with special attention given to factors that may elucidate the difference in movement at the hip on one side and the knee and ankle on the other.
Histochemical Studies on the Metabolism of L‐DOPA and Some Related Substances in the Exocrine Pancreas
Authors: Alm P. , Ehinger B. , Falck B.
Published: December 2008

The turnover of L‐DOPA and some related substances was studied with the fluorescence method of Falck and Hillarp. All the amino acids injected were easily taken up by the pancreas. This, however, was not the case with the corresponding amines. Only after L‐DOPA and DA administration, fluorescent granules could be seen in the apical zones of the exocrine cells. These granules were found to be identical with the zymogen granules. Decarboxylase inhibition prevented and MAO and COMT inhibition prolonged the appearance of the fluorescent granules. This indicates, that the fluorescent products stored in the zymogen granules is dopamine rather than DOPA.
Response of Isolated Muscle Spindles of the Frog to Sinusoidal Changes in Length
Authors: Jahn Samia Al Azharia
Published: December 2008

The response of isolated muscle spindles of the frog to sinusoidal vibrations was studied by subjecting the preparation to deformations of 0.15–1 mm at frequencies of 40–200 Hz. The minimum stretch required to evoke an afferent action potential in each cycle of deformation increased with frequency and reached level at 150–180 Hz. This increase was shown to be due to the visco‐elastic properties of the muscle spindle, the stiffness of the equatorial region increasing with the frequency of vibration. With an initial stretch of the “resting” spindle of 10–15 per cent and a frequency of vibrations of 120–160 Hz, one response in each cycle was evoked by displacements of the equatorial region which were the same as the threshold (T) for single stretches. Vibration at lower or higher frequencies required displacements of 1.5– 2 × T. When the initial stretch was 20–25 per cent the displacement of the equatorial region required to elicit an afferent response in each cycle was 1.5 × T at 120–160 Hz, 3 × T at 60– 80 Hz and 2–3 × T at 200 Hz. The change in threshold with frequency was similar in isolated muscle spindles to what has been described by others in Pacinian corpuscles.
The Role of Adenine Nucleotides in the Peripheral Vasodilating Effect of Thrombin
Authors: Olsson Per , Swedenborg Jesper , Teger‐Nilsson Ann‐Catrine
Published: December 2008

The experiments were designed to study the mediating mechanism for the previously demonstrated vasodilating effect of thrombin when small amounts are infused into the femoral artery of the dog. Washed blood cells, suspended in physiological saline, were incubated for a short time with small amounts of thrombin. The supernatant from such a cell suspension exerted a highly vasodilating effect when infused into the femoral artery. This vasodilating effect was compared to that of serotonin, histamine, adenosine and adenine nucleotides. Histamine, adenosine and adenine nucleotides caused the same type of reactions as that of vasoactive supernatants. By inactivation experiments, where these substances, as well as vasoactive super‐natants, were heated or incubated with plasma or ADP‐ase–ATP‐ase (Apyrase), it was concluded that the vasodilating agents in the latter are mainly ADP and to some extent ATP.
Dissociation of Histamine Release and22Na+Uptake in Rat Mast Cells Exposed to Compound 48/80 in vitro
Authors: Slorach Stuart A. , Uvnäs Börje
Published: December 2008

The relationship between22Na+uptake by, and histamine release from, rat mast cells exposed to compound 48/80in vitrohas been investigated in order to elucidate the mode of action of this releaser. The time course studies show that22Na+uptake and histamine release both begin after a latent period of about 5 sec but, whereas histamine release is complete after approximately 30 sec,22Na+uptake is not maximal until after 10 min. Assuming that22Na+and23Na+are taken up similarly, we have calculated that the quantity of23Na+taken up was insufficient to replace the amount of histamine released if an intracellular exchange of these two ions was involved. We conclude from these observations that intracellular exchange of sodium for histamine does not play a significant role in histamine release induced by compound 48/80. The large increase in22Na+uptake by mast cells exposed to compound 48/80 can be prevented by pretreating the cells with N‐ethylmaleimide or ninhydrin, which also inhibit the histamine release. We found evidence for the existence of a “sodium pump” mechanism which could be inhibited by ouabain. The histamine liberator d‐tubocurarine also produced an increase in the net22Na+uptake by mast cells but another releaser, n‐decylamine, which produces histamine release by lysis of the cell membrane, did not.
The Dynamics of the Inotropic Change Produced by Altered Pacing of Rabbit Papillary Muscle
Authors: Edman K. A. P. , Nilsson E.
Published: December 2008

The time course of the active state, the force‐velocity relationship and the series compliance of rabbit papillary muscles were studied at different inotropic states produced by altered pacing of the muscles within the range 18 to 72 stimulations per minute. The inotropic intervention produced a shift of the force‐velocity curve, without markedly changing the shape of the curve, suggesting that Vmax, the capacity to produce motion, and Pmaxthe capacity to produce tension, were affected to the same degree. Intensification of the active state in response to an increase in stimulation frequency was associated with a steeper rise of the active state and an earlier attainment of maximum. The series compliance was unaffected by the inotropic intervention. The results are taken as evidence (1) that the two parameters of the active state, Vmaxand Pmax, are governed by a common control mechanism in the excitation‐contraction coupling and (2) that the inotropic effect is due to altered kinetics of this control function. The nature of the mechanism governing the active state is discussed in relation to the slicling‐filament theory of muscular contraction.
Sampling of Nanoliter Volumes of Mammalian Subcutaneous Tissue Fluid and Ultra‐micro Flame Photometric Analyses of the K and Na Concentrations
Authors: Haljamäe Hengo
Published: December 2008

Local tissue fluid within the subcutaneous tissues of the hind legs of dogs was sampled with a liquid paraffin cavity method. The potassium and sodium concentrations of nanoliter samples of the tissue fluid were analyzed with an ultra‐micro flame photometric method and compared to the plasma concentrations of these ions. The average potassium concentration in the tissue fluid was 4.67 meq/l and the average sodium concentration was 153.4 meq/l; the corresponding plasma values were 3.78 meq/l and 142.3 meq/l respectively. The average individual potassium tissue fluid: plasma ratio was 1.25 (P<0.001 vs. 1.0) and the sodium tissue fluid: plasma ratio 1.08 (P<0.001 vs. 1.0). Possible sources of error at sampling and analyses have been evaluated. The potassium and sodium content of the local tissue fluid was higher than expected of an ultrafiltrate of plasma according to the generally accepted Gibbs‐Donnan constant (0.96) for these ions. The apparent deviation of the obtained values from the Gibbs‐Donnan constant can be explained by assuming that charged anionic macromolecules in the ground substance of the tissues affect the cation distribution in the local tissue fluid.
Adrenergic and Cholinergic Nerve Terminals in Skeletal Muscle Vessels1
Authors: Bolme Per , Fuxe Kjell
Published: December 2008

By the use of histochemical methods the enzyme acetylcholinesterase (AcChE) was visualized in nerve terminal appearing structures in the adventitia of small intramuscular arteries (30–100 μ) of cat and dog. These AcChE‐rich structures may represent cholinergir nerve terminals. Following chronic sympathectomy in dogs no AcChE‐rich nerve terminals were found in muscles on the operated side, indicating that these nerves represented sympathetic cholinergic innerva‐tion of skeletal muscle vessels, presumably the vasodilator nerves. In adjacent tissue sections of the muscle, adrenergic nerve terminals were histochemically visualized. Adrenergic nerve terminals were. seen in the same layer of the vessel wall as the cholinergic ones, i.e. in the adventitia surrounding the media. Adrenergic nerve terminals were found to innervate both large and small arteries. In muscle samples from monkey and human subjects no AcChE‐rich nerve terminals were observed around the vessels. However, adrenergic nerve terminals were found in these species with the same appearance as in cat and dog. This finding supports previous physiological experiments indicating that skeletal muscle of monkey lack sympathetic cholinergic vasodilator innervation.
Extraction of Dopa from the Integument of Pigmented Animals
Authors: Cegrell L. , Falck B. , Rosengren A.‐M.
Published: December 2008

The occurrence of high amounts of dopa has been demonstrated chemically in the piliary system of pigmented animals (guinea‐pig, rabbit, and dog). Histochemically, a formaldehyde‐induced fluorescence was recorded only in melanocytes of hair‐bulbs. The spectral characterictics of these cells did not agree with those of the authentic dopa fluorophore. The discrepancy between the chemical and histochemical findings is discussed. Little or no dopa was found in non‐pigmented skin of albino and multi‐coloured guinea‐pigs. This indicates that the integumentary dopa is related to the pigment formation.
Adrenergic Innervation and Structure of the Bull Retractor Penis Muscle
Authors: Klinge E. , Pohto P. , Solatunturi E.
Published: December 2008

The structure of the retractor penis muscle of the bull was examined by staining with hematoxylin and eosin. The autonomic innervation of the muscle was investigated by applying formaldehyde‐ipduced catechol amine fluorescence and the copper ferricyanide modification of the original thiocholine method for cholinesterases. It was found that the muscle consists of smooth muscle fibres only. A rich adrenergic innervation was detected. Acetylcholinesterase was also found in the nerves. The distribution of noradrenaline and acetylcholinesterase within the nerves showed some correspondence. The functional significance of the findings is briefly discussed.
Potassium Transport in Single Mammalian Skeletal Muscle Cells during in vitro Incubation
Authors: Haljamäe Hengo
Published: December 2008

Single skeletal muscle cells were isolated after varying intervals of in vitro incubation at 20–22°C from a muscle biopsy of the adductor muscle of dogs. From each isolated fibre 3–4 pieces, 70–90 μ long, were cut out and analyzed separately. Dry mass was calculated from x‐ray absorption measurements. The potassium content was determined from x‐ray fluorescence microanalysis and from ultra‐micro flame photometric analysis.

During the first 30–40 rnin of in vitro incubation profound changes in cellular potassium content took place. Cells isolated during the first few min of incubation usually had a lower potassium content than cells isolated after 5 to 10 min. In the period 10 to 25 rnin after the initiation of incubation the cells started to loose intracellular potassium. This cellular potas sium loss was followed by a period of reaccumulation, since cells isolated 30 to 45 rnin after initiating incubation usually had a potassium content as high as that of cells isolated after 5 to 10 rnin of incubation. When the sodium pump was inhibited by addition of 10‐3M ouabain to the incubation medium or if glycolysis was inhibited by 10‐3M monoiodoacetate, no reaccumulation of intracellular potassium was seen. 10‐3M 2.4‐clinitrophenol produced a pro found rapid loss of cellular potassium. It therefore appears that the reaccumulation of cellular potassium after the period of cellular potassium loss was dependent on the integrity of the sodium pump and a source of energy. The possible basis for the profund cellular electrolyte changes which occur during in vitro incubation are discussed.
The Distribution of Sodium, Potassium and Chloride in the Smooth Muscle of the Rat Portal Vein
Authors: Haljamäe Hengo , Johansson Börje , Jonsson Olof , Röcker Hans
Published: December 2008

The contents of Na and K in isolated preparations of the rat portal vein were determined by micro flame photometry, and the distribution volumes of24Na,42K and36Cl in this vascular muscle were measured after incubation periods of variable duration. The results indicate the following total ion concentrations in the vessel wall: Na 94.5; K 51.2 and C1 100 meq/kg wet weight. Evidence was obtained for the existence of “bound” fractions of the three ions and a series of experiments was designed to determine the size of these extra compartments. Data from these experiments and measurements of total water and of extracellular space by sucrose‐14C allowed calculation of intracellular ion concentrations. The following values in meq/I intracellular fluid were obtained: [Na+]i 44.8; [K+]i 138 and [Cl‐]i 86.5. The equilibrium poten tials for the three ions would then be +30, ‐44 and ‐12 mV, respectively. Functional im plications of this ionic distribution are discussed.

Measurements of total K contents and of extracellular space in portal vein preparations in cubated in hyperosmotic solution (Krebs +150 mmoles sucrose/l) indicated a clear‐cut in crease of [K+]i due to osmotic dehydration of the cells. A net loss of K seemed to occur with long periods of incubation in hyperosmotic solution.
The Effect of Some Substances on the Isolated Bull Retractor Penis Muscle
Authors: Klinge Erik
Published: December 2008

The effect of catechol amines, other biogenic amines and polypeptides, acetylcholine and other choline esters, nicotine, and various autonomic blocking agents on strips of the bull retractor penis suspended in Tyrode solution was studied. The strips were vigorously contracted by low concentrations of adrenaline and noradrenaline but they were most insensitive to acetylcholine and other choline esters. The catechol amine‐induced contractions were inhibited by low con centrations of phenoxybenzamine. The relaxations produced by isoprenaline were inhibited by pronethalol. It is suggested that the tonic contraction of the muscle is maintained by a continuous discharge of adrenergic nerve impulses. The hypothesis is presented that relaxation occurs at interruption of the adrenergic activity by impulses conducted mainly along the pelvic nerves. The pelvic nerves probably form cholinergic ganglionic or postganglionic inhibitory synapses with the adrenergic nerves concerned, The peripheral autonomic mechanism of penile erection is discussed on the presumption that the muscles of the penile artery are subjected to a similar nervous control as the retractor penis. It is assumed that there are no differences in principle between bulls and dogs with respect to the nervous mechanisms in question.
The Effect of Epinephrine and Dibutyryl 3‘,5’ Cyclic AMP on the Incorporation of32P Inorganic Phosphate into Adenine Nucleotides and Guanine Nucleotides of the Intact Isolated Rat Diaphragm
Authors: Walaas Eva , Walaas Otto
Published: December 2008

The influence of epinephrine and dibutyryl 3′,5′ cyclic AMP on the incorporation of32P inorganic phosphate into adenine nucleotides and guanine nucleotides in the rat diaphragm has been investigated. Intact rat diaphragms were incubated in Krebs Ringer bicarbonate medium containing32P inorganic phosphate without added substrate. Epinephrine promoted a marked increase of the specific activity of ATP, GTP and GDP which could be demonstrated after 10 min incubation. The specific activity of ADP was less and only slightly increased by epinephrine. In the presence of caffeine the stimulation of32P labelling of ATP by epinephrine was slightly enhanced. Epinephrine also promoted an increase of the specific activity of intracellular inorganic phosphate while the content of inorganic phosphate in the diaphragm was slightly decreased. The stimulatory effect of epinephrine on the specific activity of mononucleotides was not inhibited by ouabain. In a medium where sodium chloride isoosmotically had been replaced by choline chloride32P labelling of ATP was greatly depressed. Under these conditions epinephrine also promoted increased specific activity of ATP. During incubation of the diaphragm in the presence of dibutyryl 3′,5′ cyclic AMP increased32P labelling of ATP and ADP did occur. The effect was less pronounced than observed with epinephrine and no effect by dibutyryl 3′,5′ cyclic AMP on the specific activity of intracellular inorganic phosphate was observed. It is indicated that the increased incorporation of32P inorganic phosphate into mononucleotides promoted by epinephrine is due to activation of adenyl cyclase as well as to increased influx of32P inorganic phosphate from the medium.
Time Course of Anaphylactic Histamine Release and Morphological Changes in Rat Peritoneal Mast Cells
Authors: Bloom Gunnar D. , Chakravarty Nirmal
Published: December 2008

Anaphylactic histamine release and concomitant morphological changes were studied in rat peritoneal mast cells. It was found that anaphylactic histamine release has a longer lag period than compound 48/80‐induced release. The time sequence of the morphological changes showed a close correlation to the histamine release. These changes were essentially characterized by vacuolation, granule alteration and granule extrusion. Some peripheral granules were extruded with only minor changes. The ultrastructural findings are consistent with a dual mechanism of histamine release—both intracellular and extracellular following granule extrusion.
The Diurnal Rhythm of Adrenaline Secretion in Subjects with Different Working Habits
Authors: Pátkai Paula
Published: December 2008

Pátkai, P. The diurnal rhythm of adrenaline secretion in subjects with different working habits. Acta physiol. scand. 1971. 81. 30–34.

Subjects classified as habitual morning vs. evening workers on the basis of their answers to a questionnaire, were compared with regard to catecholamine excretion under conditions of relaxation in the morning and in the evening. It was shown that individuals who preferred to work in the evening, excreted more adrenaline in the evening than in the morning, while individuals characterized by morning alertness excreted more adrenaline in the morning than in the evening, also when relaxing. With regard to noradrenaline excretion there was no marked difference between the groups.
Effect of Prolonged Chloralose Anesthesia on Acid‐Base Balance and Cardiovascular Functions in Dogs
Authors: Arfors K.‐E. , Arturson G. , Malmberg P.
Published: December 2008

Arfors, K.‐E., G. Artursonand P. Malmberg,Effect of prolonged chloralose anesthesia on acid‐base balance and cardiovascular functions in dogs. Acta physiol. scand. 1971.81. 47–53.

Dogs under light even α‐chloralose anesthesia of 6 hrs duration showed no time dependent effect of anesthesia on mean arterial pressure, cardiac index and oxygen consumption. The Pacon remained stable as did respiratory rate, but base excess decreased moderately and heart rate increased. Compared with a group of conscious dogs Paco2and mean arterial pressure were slightly increased.
Studies of Blood‐pressure Regulation III. Dynamics of Arterial Blood Pressure on Carotid‐sinus Nerve Stimulation
Authors: ÖBerg P. A. , Sjöstrand U.
Published: December 2008

Öberg, P. Å. and U. Sjöstrand, Studies of blood‐pressure regulation. III. Dynamics of arterial blood pressure on carotid‐sinus nerve stimulation. Acta physiol. scand. 1971. 81. 96–109.

An analysis of the properties of the blood pressure regulatory system has been made by means of carotid‐sinus nerve stimulation. The method used involves analog simulation of the nonlinear properties of this reflex. The analysis gives the gain‐frequency and the gain‐phase shift curves characterizing the system under study. A resonance frequency for the system is mostly found in the frequency range 0.03–0.06 Hz. Modulation of the control signal decreases the systemic bandwidth. Non‐linear simulation indicates that the mammalian blood pressure regulating system has some of the characteristics of a sampled regulatory system. The afferent information in the carotid‐sinus baroreceptor reflex stabilizes the systemic blood pressure by means of its pulsating nature. Transfer functions characterizing the system under study are given. The data presented are relevant to the functional characteristics of baropacer systems.
Glucose Uptake at Rest and During Contraction in Isolated Dog Skeletal Muscle1
Authors: Costin Jimmy C. , Saltin Bengt , Skinner N. Sheldon , Vastagh George
Published: December 2008

Costin, J. C., B. Saltin, N. S. Skinner, Jr. and G. Vastagh,Glucose uptake at rest and during contraction in isolated dog skeletal muscle. Acta physiol. scand. 1971.81. 124–137.

In an in situ isolated canine gracilis muscle preparation the a‐v difference for glucose, oxygen, and lactate has been studied at rest and during stimulation. Both free flow (systemic blood flow) and constant flow perfusion (blood from reservoir) have been applied and in both sets of experiments the blood flow has been determined. In the constant flow experiments no significant difference in the glucose uptake could be detected between stimulation as compared with rest. In the free flow experiments the same stimulation frequency produced a significant uptake of glucose (≅ 20 μgglucose per g muscle and minute), which could account for approximately 10 per cent of the total energy output and 20–30 per cent of the total carbohydrate utilization. It is suggested that the difference between the free flow and the constant flow experiments was due to the fact that, in the free flow experiments where the muscle is perfused with the systemic blood flow, some humoral factor is present which is necessary for the glucose to penetrate the cell barrier. It was also possible to demonstrate a transient glucose uptake in the muscle in the constant flow experiments,i.e. when the muscle was suddenly perfused with blood containing a high glucose concentration (≅ 150 mg/100 ml blood).
Ventilation and Heart‐Rate Responses to Ramp‐Function Changes in Work Load
Authors: Karlsson H. , Wigertz O.
Published: December 2008

Ventilation and heart‐rate responses were recorded continuously and simultaneously during supine leg exercise in six male athletes using positive and negative ramp changes in work load, starting or ending at the fixed minimal and maximal load levels of 250 and 1050 kpm/min. The parameter Tl (“lag time”) is used to define the time by which a ramp response in its stationary condition lags behind the input signal. Three different positive and negative ramp slopes were used, the durations of the ramps being 7, 5 and 3 min (= 114, 160 and 267 kpm min‐2). For ventilation Tl was found to be largely independent of the slope of the ramp and averaged 66 sec. For heart rate, on the other hand, the mean values for Tl obtained from the responses to corresponding positive and negative slopes were 84.0, 56.4 and 38.8 sec, respectively, and proved to be significantly shorter the steeper the ramp. Granted second‐order dynamics of the heart‐rate response to work load, the slope‐dependence of Tl suggests that the share of the shorter time constant becomes larger the steeper the ramp. For the responses of the heart rate to the two steepest ramps, Tl was negatively correlated to work capacity (r= ‐0.968 and ‐0.824).
Whole‐Blood Viscosity, Hematocrit and Plasma Protein in Normal Subjects at Different Ages
Authors: Kampmann J. Ditzel J.
Published: December 2008

Whole‐blood viscosity was measured at six fixed shear rates with a cone‐plate viscometer. The 90 healthy subjects were evenly divided as to sex in three age groups from 15 to 80 years. They were selected by the criteria: normal haematocrit, erythrocyte sedimentation rate, serum creatinine concentration, and degree of intravascular erythrocyte aggregation evaluated by con‐junctival biomicroscopy; and free of disease affecting known rheological properties of the blood. The viscosity was higher in males than in females. Age was not consistently related to whole‐blood viscosity except that women of the oldest age group had a higher whole‐blood viscosity at two isolated shear rates than women in the youngest group and the plasma fibrinogen concentration was higher in the old than in the young women.

A stepwise regression analysis of rheological factors and whole‐blood viscosity showed that the hematocrit had by far the closest relation to the whole‐blood viscosity at all shear rates. In the order of decreasing influence were the alpha‐globulins, fibrinogen, and serum albumin. There was a sex difference in that the whole‐blood viscosity of men was related to the concentration of alphas‐globulin, whereas in women the relation was to the alphai‐globulin.
Elimination of 125I‐Trypsin α‐Macroglobulin Complexes from Blood by Reticuloendothelial Cells in Dog
Authors: Ohlsson K.
Published: December 2008

Complexes of 125I‐labelled bovine trypsin and the α1‐ and α2‐macroglobulins of the dog were prepared and injected into 3 dogs. The rate of elimination of the radioactivity with a half time of only 8 min fitted a single exponential curve. About 80 % of the radioactivity in the whelps and about 85 % in the adult dog was recovered in the reticuloendothelial cells of the liver, spleen and bone marrow.
Comparative Effects of Angiotensin and Noradrenaline on Resistance, Capacitance, and Precapillary Sphincter Vessels in Cat Skeletal Muscle
Authors: Järhult Johannes
Published: December 2008

The effects of intra‐arterially infused angiotensin II andl‐noradrenaline on consecutive vascular sections were studied in a sympathectomized skeletal muscle region in the cat under conditions of constant perfusion pressure. Noradrenaline was found to be an effective constrictor of precapillary resistance vessels and capacitance vessels, but a poor constrictor of precapillary “sphincters”, whereas angiotensin was an effective constrictor of precapillary resistance vessels and precapillary “sphincters”, but a poor constrictor of the main capacitance vessels. Noradrenaline caused a net fluid absorption and angiotensin a net filtration across the capillaries which indicated that noradrenaline was a poor, but angiotensin an effective, constrictor of post‐capillary resistance vessels.
Effects of Variations in the Extracellular Osmolality on the Ionic Permeability of Vascular Smooth Muscle
Authors: Jonsson Olof
Published: December 2008

The effect of osmolality variations on the membrane permeability of vascular smooth muscle to sodium and potassium was investigated by studying the washout of 24Na and 41K at different extracellular tonicities. The K efflux in normal Krebs was 4.1 10‐12 M/cm2 sec at 37° C and 2.0 10‐12 M/cm2 sec at 15° C. The corresponding Pk values were 9.4 10‐8 and 5.3 10‐8 cm/sec, respectively, assuming a membrane potential of 50 mV at 37° C and 40 mV at 15° C.

A substantial fraction of the sodium content of the portal vein prevails in an osmotically inactive bound form, as demonstrated in uptake studies on preparations where cell membranes had been destroyed so as to give a homogenous tissue fluid phase (Haljamäe et al. 1970). The present 24Na washout experiments performed on “normal” portal vein tissues were for this reason completed with studies of 24Na efflux from such damaged veins. Evidence is presented for the existence of one intra‐cellular and one extracellular fraction of bound sodium. Subtraction of that component in the washout curve which represented the intracellularly bound Na fraction would yield the exchange kinetics of the “free” intracellular sodium. The magnitude and efflux of [Na+]1, thus calculated, amounted to 13.1 meq/l and 1.2 10‐12 M/cm2 sec at 15° C.

Assuming, on the basis of indirect experimental evidence, that Na influx equals Na efflux in the experimental situation, a passive permeability coefficient for Na of 4.3 10‐9 cm/sec was calculated, giving a Pna/Pk ratio of 0.081. The washout experiments performed in anisosmotic media indicated that this ratio increased when osmolality was lowered, which might in part explain the strong enhancement of the spontaneous activity induced by hypotonicity. The results did not, however, indicate any clearcut alteration in either Pna, or Pk when the muscle cells were exposed to hypertonicity.
Dissociation of Tracer Disappearance Rate and Blood Flow in Isolated Skeletal Muscle during Various Vascular Reactions
Authors: Bolme Per , Edwall Lennart
Published: December 2008

The rate of disappearance of diffusible radioactive tracers (xenon and iodide) and blood flow were measured in the canine gastrocnemius muscle. A transport‐flow index (TFI) showing the ratio between disappearance rate and blood flow was calculated. Metabolic vasodilatation resulted in TFI values between 2 and 3. These values were higher than those following intra‐arterial infusion of acetylcholine, indicating that metabolic vasodilatation causes a higher net transport of tracer between tissue and blood than i.a. infusion of acetylcholine. Reduction of blood flow by low frequency stimulation of vasoconstrictor nerves or by i.a. infusion of nor‐adrenaline resulted in TFI:s approaching 1, indicating an approximately equal effect on tracer transport and blood flow. However, high frequency stimulation of vasoconstrictor nerves re duced tracer transport more than blood flow. During partial occlusion of the arterial inflow, the iodide TFI was greater than 1, suggesting a compensatory increase in tracer transport relative to blood flow. The present results indicate that the disappearance rates of xenon and iodide are not only dependent on total blood flow in the muscle but are also influenced by local factors in the capillary section affecting the exchange function. Thus the calculation of muscle blood flow from xenon disappearance data alone may give misleading results.
Inotropic and Metabolic Effects of Dibutyryl Cyclic Adenosine 3‘, 5’‐Monophosphate in the Perfused Rat Heart
Authors: Ahrén Kurt , Hjalmarson ÅKe , Isaksson Olle
Published: December 2008

The isolated, working rat heart preparation was used to study whether dibutyryl cyclic adenosine 3′,5′‐monophosphate could reproduce the inotropic and nietabolic effects of catecholamines in the heart. The effects of dibutyryl cyclic AMP and adrenaline were studied in absence and presence of aβ‐receptor blocking agent (propranolol). Heart rate, cardiac output, peak systolic pressure, glycogen content, lactate production and concentrations of ATP and creatine‐phosphate were measured.

Dibutyryl cyclic AMP (5×10‐3M and higher concentrations) evoked a positive inotropic effect as measured by an increase in peak systolic pressure, when the heart rate was kept constant by electrical stimulation. The nucleotide also produced a marked and concentration dependent (10‐5to10‐3) glycogenolytic effect. Propranolol (10‐5M) blocked the inotropic and glycogenolytic effects of adrenaline, but did not reduce the effects of dibutyryl cyclic AMP. The effects of adrenaline were seen already 1 min after its addition to the perfusion medium, while the effects of dibutyryl cyclic AMP were not seen until 3–5 min after addition of the nucleotide. In time course studies, no dissociation was observed between mechanical and metabolic effects of the nucleotide.