bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rise Time of the Spike Potential in Fast and Slowly Contracting Muscle of Man
Authors: Buchthal Fritz , Dahl Kristian , Rosenfalck Poul 
Published: December 2008

AbstractIn 20 muscles of 10 normal Subjects rise times of the spikes of motor unit potentials were recorded during weak voluntary effort by means of a concentric electrode with a small tip area (0.015 mm2). Rise times in the soleus muscle, which consists mainly of slowly contracting fibres, were twice as long on the average as in the lateral head of the brachial triceps, which contains mainly fast contracting fibres (190 ± 10 μs, 145 spike potentials compared to 107 ± 4 μs, 115 spike potentials), In both muscles the distribution of rise times was skewed toward the long rise times. The longer rise times in the soleus muscle could not be accounted for by smaller diameter of the muscle fibres and therefore slower conduction velocity than in the lateral head of the brachial triceps. Therefore the properties of the excitable membrane must be different in the slow fibres of the soleus from those of the fast fibres of the lateral head of the brachial triceps. The difference in rise time of the spikes in the two muscles was not reflected in the total duration ol the motor unit potentials recorded by means of conventional concentric electrodes.
Histochemically Demonstrable Catecholamines and Cholinesterases of the Rat Uterus during Estrus Cycle, Pregnancy and after Estrogen Treatment
Authors: Hervonen Antti , Kanerva Lase , Lietzén Ralf 
Published: December 2008

AbstractThe changes of the adrenergic and cholinergic nerves of the rat uterus were examined during the estrous cycle, pregnancy and after estrogen treatment. During the first 2 weeks of pregnancy and after estrogen treatment the fluorescence intensity and the thickness of the extra‐vascular adrenergic nerve fibres increased, but decreased in the end of pregnancy. The activity and also the density of AChE‐positive nerves increased after estrogen treatment and during the first 2 weeks of pregnancy and decreased at the end of pregnancy. The AChE‐activity and the intensity of fluorescence in the nerves was somewhat stronger in estrus than diestrus.
Relationship between Cyclic AMP, Phosphodiesterase Activity, Calcium and Contraction in Intestinal Smooth Muscle
Authors: Andersson Rolf G. G. 
Published: December 2008

AbstractEffects of contracting agents on the mechanical and the metabolic activity in smooth muscle have been studied. The contraction induced by carbacholine in colon muscle from rabbit was preceded by a decrease of the cyclic AMP content. After development of the tension, the level of cyclic AMP was increased, the phosphodiesterase activity was reduced, and the phosphorylase SaL activity and glycogenosis were stimulated. These effects were blocked by atropine but not by an adrenergic β‐blocking agent. In the Ca‐poor muscle there was a sustained decrease of the cyclic AMP content by carbacholine. Contraction induced by K+ions showed similar metabolic actions as carbacholine and these effects were Ca++dependent too. The contracting effect of imidazole was preceded by an activation of phosphodiesterase and by reduction of cyclic AMP. The metabolic effects induced by imidazole were not Ca++dependent. Imidazole potentiated the contracting action of carbacholine and K+. Ca++in the same concentrations as those activating the contractile system, inhibited the phosphodiesterase activity in homogenate of colon muscle. The relationship between cyclic AMP, Ca++and contraction in smooth muscle is discussed.
Glycogen Synthesis in Rat Diaphragm in Vivo: a Biphasic Effect of Insulin on Glycogen Synthetase Enzyme
Authors: Adolfsson Sten 
Published: December 2008

AbstractDuring enhanced glycogen synthesis an increase in the activity of the enzyme rate‐limiting for glycogen synthesis is expected. This enzyme, glycogen synthetase (UDP‐glucose: α‐1,4‐glucan, α‐4‐glucosyltransferase; EC 2.4.1.11), can be activated by transformation of its D‐form to I‐form. Insulin is known to stimulate glycogen synthesis in skeletal muscle. However, Søvik did not find any change in I‐form in the rat diaphragm 30–240 min after an intraperitoneal (i.p.) injection of insulin, although glycogen synthesis was highly stimulated (O. Søvik, Acta physiol. scand. 1966.68.246–254). In the present study glycogen content and synthetase enzyme activity were measured in rat diaphragms 10–120 min after i.p. injection of insulin. Phosphorylase enzyme activity was also measured. Insulin administration produced a biphasic change in the synthetase enzyme; compared to controls there was an increase of the % I‐form after 10 and 20 min and a decrease after 50, 80 and 120 min. Phosphorylase enzyme activity was unaffected. Glycogen increased continuously up to 120 min. Thus, the increase in I‐form was shown to be a transient effect of insulin. In Søvik's experiment this increase had probably subsided at the time of the first measurement. To account for the increase in glycogen when the % I‐form was decreased, an activation of the synthetase enzyme through an increase of its activator, glucose‐6‐phosphate, may be considered.
Effect of Physical and Chemical Agents on the Blood Mast Cells (Basophil Leucocytes) of Turtles
Authors: Reite Ola B. 
Published: December 2008

AbstractThe histamine‐releasing effect of several physical and chemical agents on basophil leucocytes was studied in blood from the red‐eared turtle,Pseudemys scripta elegans.Hypotonic saline, low and high pH, compound 48/80 and octylamine produced marked histamine release. Polymyxin B, toluidine blue and protamine seemed to be capable of inducing release of smaller amounts of histamine. No significant histamine release was obtained with hypertonic saline, d‐tubocurarine, reserpine, adrenaline and 5‐hydroxytryptamine. It is concluded that compared with the tissue mast cells of the rat, in which the response to histamine‐releasing agents has been thoroughly studied, the basophil leucocytes of the turtle are considerably more resistant to induced release of histamine.
Circulatory Responses to Stimulation of Left Ventricular Receptors in the Cat
Authors: ÖBerg Bengt , Thorén Peter 
Published: December 2008

AbstractLeft ventricular receptors, firing in non‐medullated vagal afferents, were stimulated in chloralose‐anesthetized cats by brief aortic occlusions or by intrapericardial injections of nicotine. The induced reflex effects on heart rate, renal and skeletal muscle resistance vessels and muscle capacitance vessels were followed and compared with the reflex effects of arterial baroreceptor stimulation. Stimulation of the ventricular receptors induced a considerable reduction in heart rate, almost entirely due to vagal activation, and to a reflex dilatation of renal and muscle resistance vessels and of the muscle capacitance vessels. For a given reflex reduction of skeletal muscle flow resistance with the two reflex mechanisms, the concomitant reflex bradycardia and renal vasodilatation was more pronounced when the ventricular receptors were stimulated than upon activation of the arterial baroreceptors. The capacitance vessels seemed, however, to be engaged to the same extent from the two receptor groups. The reflex muscle dilatation, following ventricular receptor activation, was solely due to inhibition of adrenergic vasoconstrictor fibre activity with no evidence of any cholinergic vasodilator fibre activation.
Redistribution of Tissue Histamine Stores (Basophil Leucocytes) of Turtles in Response to Submersion and Cold Exposure
Authors: Reite Ola B. 
Published: December 2008

AbstractThe histamine contents of liver and blood of turtles(Pseudcmys scripta elegans)kept at 20–22° C were compared with those of turtles exposed to cold (4–6° C) for 2–21 days or sub‐merged for 12 hours. Submersion and cold exposure consistently caused a decrease in the histamine content of blood and an increase in the histamine content of liver. The average histamine content of blood was reduced to about half its pre‐exposure value and that of liver was doubled. The results indicate that the basophil leucocytes, which are exceptionally numerous in this species and are the only blood cells known to contain appreciable amounts of histamine, accumulate in the liver when the turtles are submerged or exposed to cold. Influence of cold exposure on the histamine content of liver and blood was also studied in several other species of turtle(Chrysemys picta, Emys orbicularis, Clcmmys caspica leprosa, Terrapcne Carolina, Kinosternon flaucscens), and they all showed a response similar to that observed inPseudemys scripta clcgans.
Lack of Correlation between Profiles of Transmitter Efflux and of Muscular Contraction in Response to Nerve Stimulation in Isolated Guinea‐pig Vas Deferens
Authors: Stjärne Lennart 
Published: December 2008

AbstractThe profile of the nerve stimulation induced contractile response of isolated, superfused guinea‐pig vas deferens was compared with that of transmitter efflux, as monitored by determination of outflow of total tritium, after preincubation with tritium‐labelled nor‐adrenaline. Transmitter efflux increased with time during stimulation up to 60 s and was monophasic, although the contractile response could be made to shift from mono‐to diphasic. Desipramine and normetanephrine added to block local reuptake of noradrenaline altered the slope, but not the monophasic character of the transmitter outflow curve. Phenoxybenz‐amine abolished the delayed contractile response to nerve stirnulation, but potentiated and shortened the latency of the initial “twitch”. In spite of the presence of drugs blocking reuptake of noradrenaline phenoxybenzamine further markedly enhanced nerve stimulation induced transmitter efflux, indicating that blocking of specific α‐adrenoceptors leads to enhanced transmitter secretion. Further addition of prostaglandin E2distinctly potentiated, and prolonged the latency of, the initial “twitch”, but depressed the secretion of transmitter. All these effects increased with the dose of prostaglandin, and were reversible. The results clearly show the sometimes striking lack of correlation between transmitter secretion and the resulting mechanical response; actual determination of transmitter efflux improves on the accuracy of conclusions concerning mechanisms controlling secretory events at this level.
The Effect of Hypertonicity on the Time Course of the Active State in Single Skeletal Muscle Fibres of the Frog
Authors: Andersson K.‐E. 
Published: December 2008

AbstractThe time course of the active state was investigated in single skeletal frog muscle fibres in normal Ringer's solution and in Ringer's solution made hypertonic (1.44–1.67 R) by addition of sucrose. During a single, isometric twitch the plateau phase of the active state was abbreviated in hypertonic solution. During repetitive stimulation there was a progressive increase in the duration of the active state and a slowing of the rate of decay of the activity in the hypertonic medium. The resting membrane potential was insignificantly affected by the hypertonic solutions used. There was a slight decrease in overshoot and also a diminution in the rate of rise and rate of decay of the action potential. As a possible explanation of the results, it is suggested that in a hypertonic medium there is a diminished release of calcium in response to a stimulus. This leads to a shortening of the plateau phase of the active state during a single twitch. Because of a reduced rate of re‐uptake of calcium by the sarcoplasmic reticulum, the duration of the active state is prolonged and the decay of activity slowed during repetitive stimulation.
Differences in the Autoradiographic Localization of Labelled Morphine‐Like Analgesics in the Mouse
Authors: Appelgren Lars‐Erik , Terenius Lars 
Published: December 2008

AbstractThe distribution of the3H‐labelled narcotic analgesics, dihydromorphine and fentanyl and the narcotic antagonist, diprenorphine, was studied by whole‐body autoradiography in male and female (pregnant) mice. Very small amounts of label were found in the CNS after administration of dihydromorphine which was rapidly excreted via the urine. There was very little passage of labelled material over the placental barrier. Pretreatment with nonlabelled diprenorphine did not change the distribution. After the administration of fentanyl a very different picture was seen. Large amounts of label passed into the CNS. In addition to label in urine, large amounts were seen in the gall bladder and in the intestinal contents. Only little passage over the placental barrier was observed. After the administration of diprenorphine rather little label was found in the CNS while high amounts were excreted via urinary pathways and still more via the intestine. There was considerable passage over the placentzl barrier.
Vagal Relaxation of the Stomach Induced by Apomorphine in the Cat
Authors: Abrahamsson Hasse , Jansson Gunnar , Martinson Jan 
Published: December 2008

AbstractIn anesthetized or decerebrate unanesthetized cats administration of the emetic drug apomorphine produced pronounced and long‐lasting relaxation of the stomach. When apomorphine induced somatomotor retching or vomiting movements they were always preceded by gastric relaxation. The gastric relaxatory response to apomorphine could not be blocked by atropine or guanethidine but was completely abolished after vagotomy. Vagotomy, if performed during the relaxed state of the stomach after apomorphine administration, resulted in a prompt decrease of gastric volume. Injection of apomorphine had no essential effect on gastric contractions induced by efferent electrical vagal stimulation, indicating that the splanchnic nerves were of minor or no importance for the apomorphine induced gastric relaxation.—It is concluded that the emetic drug apomorphine produces gastric relaxation by activation of the vagal non‐adrenergic relaxatory nerve fibres to the stomach. The results indicate that the relaxation of the proximal part of the stomach known to appear early in the vomiting act, is mediated by these relaxatory nerve fibres.
Protein Concentration of Interstitial Fluid Collected from Rat Skin by a Wick Method
Authors: Aukland K. , Fadnes H. O. 
Published: December 2008

AbstractA new method has been developed for studying interstitial fluid protein concentration: A 3 cm long and 0.5 mm thick nylon thread was sewn into subcutaneous tissue of ether anesthetized rats and left for equilibration with interstitial fluid for 35 to 240 min. The wick was then pulled out, both ends cut off, and the middle part quickly transferred to a tared vial containing 2 ml saline and weighed. Blood‐stained wicks, about 1 out of 5, were discarded. After 24 h elution the wick was removed, dried and weighed, allowing calculation of wick fluid volume. Total protein, albumin and hemoglobin concentrations were measured in the eluate. Hemoglobin concentration was less than 0.2 g/100 ml in all but one wick. Implantation of 73 wicks in 24 rats for 35 to 120 min gave an average albumin concentration of 2.10 (S.D. 0.24) g/100 ml, or 63% of plasma albumin concentration. Total protein concentration in 80 wicks averaged 3.44 (S.D. 0.30) g/100 ml, 56% of plasma. The concentrations did not change during this time interval and were reduced by less than 10% by antihistamine/antiserotonin treatment. An irregular rise in concentrations after more than 2 h implantation was delayed by antihistamine/antiserotonin.
Sequential Exocytosis of Storage Granules during Antigen‐Induced Histamine Release from Sensitized Rat Mast Cells in vitro An electron microscopic study
Authors: Anderson Per , Slorach Stuart A. , Uvnäs Börje 
Published: December 2008

AbstractThe morphological changes appearing in sensitized rat mast cells incubated with antigen at 25° C for times ranging from 30 s to 10 min were studied using light and electron microscopy. Histamine release was assayed in parallel. After a latent period of 30 s, during which no histamine release or morphological changes occurred, degranulation and histamine release commenced and increased progressively with time. The first changes were seen in the most peripherally‐located granules, and consisted of a fusion of the cell membrane with the perigranular membrane and a swelling and a reduction of the electron‐density of the granules. With increasing time these changes were seen to spread deeper into the cells, resulting in the formation of labyrinthic cavities contatining changed granules; such granules were also seen outside the cells. Using the extracellular tracer lanthanum these apparently intracellular cavities were demonstrated to be in unbroken communication with the extracellular milieu. Thus when sensitized rat mast cells are incubated with antigen sequential exocytosis of histamine‐storing granules take place. The results agree with the hypothesis that histamine release takes place by ion exchange between histamine and extracellular cations both in granules expelled from the cells and in those retained in cavities open to the exterior.
Potentiation of Anaphylactic Histamine Release from Guinea Pig Lung by Maleate and Succinate
Authors: Chakravarty Nirmal , Sørensen Hans Jørgen 
Published: December 2008

AbstractBoth maleic acid and succinic acid enhance anaphylactic histamine release from guinea pig lungin vitro–the degree of enhancement being of the same order of magnitude. The stimulating effect of both the substrates is inhibited by relatively low concentrations of malonic acid and bromopyruvic acid, and no stimulation occurs in response to either substrate when histamine is released by the antigen in an anaerobic medium. Maleic acid is shown to be metabolized to CO2by guinea pig lung nearly at the same rate as the tissue oxidizes succinic acid to CO2–the conversion of both the substrates to CO2beifig inhibited by malonic acid. Furthermore, D (+) malic acid has been identified as an intermediate product in the metabolism of maleic acid by guinea pig lung. It is suggested that maleic acid follows the same metabolic pathway in guinea pig lung as revealed earlier in rabbit kidney,viz.maleic acid → D (+) malic acid → oxaloacetic acid → CO2. The findings thus suggest that both maleic acid and succinic acid enhance anaphylactic histamine release from guinea pig lung through their metabolic utilization in the tricarboxylic acid cycle.
Potentiation of Dextran‐Induced Histamine Release from Rat Mast Cells by Phosphatidyl Serine
Authors: Chakravarty Nirmal , Goth Andres , Sen Parantapa 
Published: December 2008

AbstractPhosphatidyl serine in 1–50 μg/ml concentrations markedly potentiates histamine release in‐duced by dextranin vitrofrom the mixed peritoneal cells of rats. The release occurs within one‐half minute, thus resembling the anaphylactic histamine release. The histamine release from isolated pure populations of mast cells, which generally respond poorly to dextran, was largely restored by phosphatidyl serine. The media, employed for the isolation of mast cells, viz. serum albumin, Ficol and acacia, were found to inhibit histamine release. The albumin inhibition could be overcome by phopshatidyl serine, which enhanced the release in spite of the presence of albumin. Serum albumin was found to bind phospholipids, an effect which may be related to the inhibition of histamine release caused by albumin. The effect of some inhibitors of the ATPase system was studied. Ouabain in 1–10 mM concentration neither affected the dextran‐induced histamine release nor its potentiation by phopshatidyl serine. Ethacrynic acid (1 mM) had some inhibitory effect on histamine release by dextran alone and dextran + phosphatidyl serine. Oligomycin (1 μg/ml) had very little effect on histamine release induced by dextran alone, but completely blocked the potentiation of histamine release caused by phosphatidyl serine.
Incorporation of Guanethidine into Isolated Rat Peritoneal Mast Cells and Mast Cell Granules in Vitro
Authors: Gripenberg J. 
Published: December 2008

AbstractThe incorporation of guanethidine into isolated rat peritoneal mast cells was studied in vitro. The incorporation of the drug is dependent upon 1. temperature, 2. the pH of the medium, 3. the presence of Ca‐ions in the medium, it 4. shows saturation characteristics and is 5. inhibited by 5‐hydroxytryptamine and tricyclic antidepressants. Of the metabolic inhibitors tested, only FCCP reduced incorporation of guanethidine. The intracellular location of guanethidine in mast cells is mainly in the amine‐storing organelles. It is concluded that the incorporation of guanethidine is partly due to an active transport mechanism located in the cell membrane, while the incorporation of the drug into isolated membrane‐free mast cell granules is a passive process resulting in binding to sites in the granule matrix.
An Investigation of the Action of Diphenylhydantoin on Sodium Efflux in Barnacle Muscle Fibres
Authors: Bittar By E. Edward , Chen Stephen S. , Danielson Bo G. , Tong Edmund Y. 
Published: December 2008

AbstractBittar, E. E., S. S. Chen, B. G. DanielsonAND E. Y. Tong. An investigation of the action of diphenylhydantoin on sodium efflux in barnacle muscle fibres. Acta physiol. scand. 1973. 89. 30–38.Sodium efflux from barnacle fibres is suppressed by external but not by internal application of diphenylhydantoin (DPH). DPH (10‐4M) at pH 7.8 reduces the Na efflux by 32%,a value slightly less than half that obtained with 10‐4M ouabain. Ouabain has the ability to abolish the remaining Na efflux, whereas DPH incompletely abolishes the ouabain‐insensitive Na efflux. The onset of inhibition by DPH is slower than that by ouabain. At lower external pH the onset of peak action by DPH is more rapid than at pH 7.8. The sensitivity of the Na efflux to DPH is unaffected by external K. However, the residual efflux from fibers poisoned with ouabain following K removal is insensitive to DPH. DPH prevents the Na efflux from responding to external acidification. It also has the power to almost completely reverse the effect of external acidification on the Na efflux. It is provisionally concluded that the T‐system is the site of DPH action.
Histaminuria after Parenteral L‐histidine Administration in Man
Authors: Döhlen Helene , Nornes Helge , Sjaastad Ottar , Sjaastad Ö. V. 
Published: December 2008

AbstractDohlen, H., H. Nornes, O. SjaastadAND Ö. V. Sjaastad. Histaminuria after parenteral L‐histidine administration in man. Acta physiol. scand. 1973. 89 51–60.L‐histidine was given i.v. to 4 healthy male individuals. The dosage was 2.5, 5.0 and 7.5 g of the free amino acid, and the total number of experiments 9. The urinary excretion of histamine was estimated with 3 different methods: Dunér and Pernow's method (ion‐exchange + bioassay), an enzymatic isotopic assay (Snyder et al.1966) and an autoradiographic method. No definite increment in urinary histamine excretion followed the 2.5 g dose, whereas a significant increment followed the 5.0 and 7.5gdosages. The excess histamine was excreted during the first 4 h after L‐histidine loading. The excess urinary histamine probably has its origin in the tissues of the body. The extra endogenous histamine is probably formed as a consequence of the L‐histidine loading.