bluuebunny/crossref_metadata_2025_split huggingface dataset:
Membrane Potential and Conductance during Piocytosis Induced in Amoeba proteus with Alkali Metal lons
Authors: Josefsson Jan‐Owe , Holmer Nils‐Gunnar , Hansson S. Elisabeth 
Published: December 2008

AbstractAn investigation of the relationshi between the polarized state of the membrane adn the onset and the intensity of pinocytosis was made in Amoeba proteus. Membrane potential and input resistance was in all instance found to decrease in approximate proportion to the number of channels when pinocytosis was induced by a variety of alkali metal ions at varying pH. channels began to appear when the membrane was depolarized to–30 mV by the inducer of pinocytosis. With all inducers the maximum pinocytosis was encountered at membrane potentials close to zero. No positive potentials were recorded when the chloride salts of the inducing cations were used. At high concentration of alkali ions a transient increase of the chloride permeability caused short‐lasting hyperpolarizations of the membrane. Inhibition of pinocytosis by Ca++ was accompanied by an increase of input resistance and membrance potential. The selectivity of the membrane to different alkali metal ions observed as changes in pinocytosis intensity, membrane potential and input resistance was found to vary with the concentration of the inducer and with the Ca++concentration of the extracellular solution. Displacement of membrane bound Ca++appeared to decrease the field strength of charged groups in the membrane altering its selectivity among alkali cations. The formation of pinocytotic channels in suggested to require translocation of Ca++from the membrane into the cell and would therefore be closely related to the electrical properties of the amoeba.
A Theoretical Study of Restricted Convention‐Diffusion as Applied to Blood‐Tissue Barrier Exchange
Authors: ÅBerg Bo 
Published: December 2008

AbstractThis paper handles a model of the capillary function in the exchange of uncharged molecules between the blood and the tissue. The capillary system is subdivided into a filtering and a reabsorbing part. The exchange is assumed to occur through channels which are described in operational terms as pores. Through these pores there is a transport of solutes by concomitantly acting convection and diffusion influenced by a steric hinderance (restricted convection‐diffusion). The outflux of glucose and raffinose is enhanced in the filtering pores, raffinose relatively more than glucose. In the reabsorbing pores the outward diffusion is hindered to some extent, raffinose relatively more than glucose. It is shown that the net effect of filtration and reabsorption is to increase the outflux of raffinose as compared to that of glucose. This mechanism may explain why glucose and raffinose and other small molecules appear to pass across capillary walls in proportion to their free diffusion coefficients and not in proportion to their restricted diffusion coefficients.
Integrated Somatomotor, Cardiovascular and Gastrointestinal Adjustments Induced from the Cerebellar Fastigial Nucleus
Authors: Lisander Börn , Martner Jan 
Published: December 2008

AbstractBehavioural, cardiovascular and gastric responses induced by fastigial stimulation wereobserved in conscious cats with gastric fistulas, indwelling fastigial electrodes and arterial catheters. Fastigial stimulation elicited oral behaviours, e.g. grooming and chewing, together with tachycardia and pressor responses, while gastric motility was unaffected in most cases as was gastric hydrochloric secretion. In subsequent experiments on the anesthetized animals it was found that the same fastigial area could suppress the intestino‐gastric inhibitory reflex. Fastigial influences on small intestinal motility were investigated in anesthetized cats, well recovered from surgical isolation of intestinal loops whose motility could therefore be recorded without laparotomy. Fastigial stimulation either depressed or did not influence ileal motility before laparotomy but after this procedure excitatory responses were uniformly recorded. This reversal is explained by a fastigial suppression of inhibitory intestinal reflexes, elicited by the laparotomy.
Rapid Transport of Noradrenaline in Adrenergic Axons of Rat Sciatic Nerve Distal to a Crush1
Authors: Häggendal J. , Dahlsträm A. , Larsson P. A. 
Published: December 2008

AbstractThe transport of NA in the rat sciatic nerve distal to a crush was studied in 5 mm segments. The disappearance of a NA fraction in consecutive segments with time after crushing (0–12 h) was interpreted to indicate a proximo‐distal migration of a NA fraction into further distal parts of the nerve. This transportable NA fraction was found to be about 45% of the NA in normal sciatic nerves and migrated at a rate of approximately 8 mm/h. The apparently non‐mobile fraction (55%) was probably mainly located in vaso‐constrictor nerve terminals of the blood vessels supplying the nerve. This non‐mobile NA fraction does not contribute to the NA accumulations proximal to a crush. Thus, when calculating the rate of transport of any substance from accumulation experiments, corrections for a non‐mobile fraction must always be considered.
Synaptosomes Containing Large Agranular Vesicles Isolated from Developing Rat Brain
Authors: Kanerva L. , Hervonen A. , Tissari A. H. 
Published: December 2008

AbstractUsing the subcellular fractionation technique the fine structure of the isolated nerve endings (synaptosomes) from the hemispheres and brain stem of the 1–day old and adult rat was examined. In the synaptosomal fractions of the brain of 1–day old rats we observed a new type of nerve endings containing predominantly large agranular vesicles about 1 000 Å in diameter. After incubation with a‐methylnoradrenaline or 5–hydroxydopamine these vesicles remained agranular. It is assumed that the new type of large vesicles represent developing synaptic vesicles. References
The Effect of Ca++, Mg++ and H+ on the Capillary Permeability of the rete mirabile of the Eel, Anguilla vulgaris L.
Authors: Stray‐Pedersen Sverre 
Published: December 2008

AbstractThe effects of EDTA, and of varying pH on the capillary permeability in the rete mirabile have been investigated: EDTA had to be added to the perfusate in excess to the total content of Ca++ and Mg++ in plasma in order to elicit changes in the permeability. When exposed to sufficient amounts of EDTA, the capillary permeability to hydrophilic molecules increased several fold whereas the permeability to THO and lipid‐soluble molecules remained unchanged. The increase in the permeability to high‐molecular dextrans was delayed. When the EDTA‐effect was maximal the mutual relationship between the permeabilities of THO and the lipid‐insoluble molecules became close to the ratio between the corresponding free diffusion coefficients in water. During exposure to EDTA the content of K+ and Na+ of the rete tissue (mostly endothelial cells) became very similar to that of plasma. Similar effects were obtained when the rete was perfused with plasma having a pH below 4 or above 9. The EDTA‐effect was reversible during its initial stage. Perfusions with plasma in which Ca and Mg had been removed by dialysis at pH 3.5 were performed. When an EDTA‐effect had been induced with this type of perfusates, it could be reversed by addition of equimolar amounts of either Ca++ or Mg++. This indicates Ca++ and Mg++ to be equally important in order to assure normal permeability properties of the capillary membrane.
Changes in Renal Hemodynamics and Sodium Excretion during Saline Infusion in Lambs
Authors: Aperia Anita , Broberger Ove , Herin Peter 
Published: December 2008

AbstractThe renal response to a progressive isotonic extracellular volume (ECV) expansion was studied in 13 lambs of two age groups (5–28 days and 48–57 days). Changes in renal hemodynamics induced by the ECV expansion were followed. Intraenal blood flow was determined by the microsphere method. For determination of the glomerular filtration rate (GFR) standard clearance techniques were used. Recordings were made during control conditions and when normal saline had been infused in amounts up to 4.5% of the body weight. During the infusion there was an increase in sodium excretion both in absolute values and in relationship to GFR. The increase was, however, much less pronounced in the younger lambs. The GFR did not change significantly during saline infusion. The cortical blood flow increased only in the older lambs. As a consequence the quotient between GFR and cortical blood flow decreased in the older lambs. The possibility of a causal relationship between the fall in filtration fraction so obtained and the more pronounced natriuretic response in the older lambs is discussed. The inner to outer cortical blood flow ratio increased more in the younger lambs during saline infusion. The functional significance of an age related blood flow redistribution is, however, not clear.
On the Noradrenaline Loading in Axonal Amine Storage Granules in Rat Crushed Sciated Nerves1
Authors: Dahlström A. , Häggendal J. , Larsson P. A. 
Published: December 2008

AbstractThe increase of NA in rat sciatic nerve above a crush was investigated. The transported amounts of NA did not increase quite linearly with time, but more NA was found above the crush at 6 and 12 h than would be expected from the 3 h value. One possible reason for this phenomenon—an increased NA loading of the accumulated axonal granules—was investigated by 2 types of double crush experiments. One type involved simultaneous double crushes 1‐1.5 cm apart. The increase in NA in the isolated segment 6 h after crushing indicated that the axonal amine storage granules had increased their NA load by about 70%. In the second type (“delayed double crushes”) a distal crush was made 6 h before a second crush, 1‐1.5 cm proximal to the first crush. 1–12 h after the second high crush the NA content of the isolated segment was assayed. The results indicated an increased NA content in the axonal granules of 75% already 3–4 h after the isolation of the segment, remaining constant up to 9 h after the second crush. The results indicate that axonal storage granules may increase their NA content by a factor of about 2 (1.7) while being transported distally in the axons. This information together with the information from the preceding article of a mobile NA fraction of 45%, was used to calculate the rate of transport of NA granules proximal to a crush. The value obtained was 9 mm/h which is in good agreement with the value obtained for transport distal to a crush (8 mm/h) in the preceding article.
Indomethacin Blockade of Renal PGE‐Synthesis: Effect on Total Renal and Tubular Function and Plasma Renin Concentration in Hydropenic Rats and on Their Response to Isotonic Saline
Authors: Leyssac P. P. , Christensen P. , Hill R. , Skinner S. L. 
Published: December 2008

AbstractThe effects of indomethacin (I), a blocker of prostaglandin (PG)‐synthetase, was studied in rats in an attempt to elucidate the physiological role of renal PGE. Plasma‐I‐concentrations of 13–14 μg/ml reduced renal venous plasma PGE‐concentration significantly from 216 to 85 pg/ml within 45 min. Urine flow and solute excretion decreased by 42% and 20%, respectively, while urine osmolality increased 450 mOsm. Inulin clearance (CIN) and proximal reabsorption rate was unaffected, while renal plasma flow (RPF) decreased by 18%. Plasma renin concentration decreased slightly but significantly. An i.v. saline load equal to 1% b.wt. given to I‐treated rats failed to elevate significantly either urine flow, solute excretion, CIN, RPF or proximal reabsorption rate, but plasma renin decreased further. The normal inverse relationship between plasma renin and proximal reabsorption rate was absent. The data are consistent with the concept that intrarenal PGE plays a role in adjustment of renal vascular resistance, and support the concept of a physiological role of intrarenal PGE in regulating salt and water excretion. The data do not support any major physiological role of PGE in regulating proximal tubular function.
The Biliary Excretion of 3H‐Inulin and 3H‐Terbutaline in the Unanesthetized Rat
Authors: Eriksson Hans , Hellström Wera , Ryrfeldt ÅKe 
Published: December 2008

AbstractAn animal model which permits sampling of arterial blood and bile from unanesthetized rats with uninterrupted enterohepatic circulation is described. Pharmacokinetic data concerning inulin (0.2 μmol kg‐1) and terbutaline (1.8 μmol kg‐1) after intraarterial injection are presented. The following values for inulin were obtained Vdβ= 0.25 ml g‐1 plasma clearance = 2.3 ml min‐1 kg‐1 and bile clearance = 0.03‐0.04 ml min‐l kg‐1, which mainly are in agreement with data from the literature. For terbutaline the corresponding values were 0.58 ml g‐l, 5.2 ml min‐l kg‐l and 0.12‐0.98 ml min‐1 kg‐1, respectively.
Potentiation by Prostaglandins E1, E2, and F2αof the Contraction Response to Transmural Stimulation in the Bovine Iris Sphincter Muscle
Authors: Gustafsson Lars , Hedqvist Per , Lagercrantz Hugo 
Published: December 2008

AbstractThe contraction response to transmural stimulation in the bovine iris sphincter muscle was abolished by atropine but was left virtually unchanged by hexamethonium, and by adrenergic neuron and receptor blockers, indicating activation of postganglionic cholinergic nerve fibres. Low doses of prostaglandins E1, E2and F2α(0.1–5.0 ng/ml) consistently and apparently in a dose‐dependent manner enhanced the contraction response to transmural stimulation. Prostaglandins E1and E2were equipotent while F., was at least 10 times less active. Within the same dose range the prostaglandins also enhanced the contraction response to exogenous acetylcholine, indicating that part of the enhancing effect of the prostaglandins on neuromuscular transmission was due to a postjunctional action. A spontaneous increase in tone of the preparation commonly occurred about 1 h after the beginning of the experiment. SC 19220, a potent antagonist of prostaglandin action, reduced the tone and the contraction responses as well as the enhancing effect of the prostaglandins. It is concluded that prostaglandins might serve the function of controlling neuroeffector transmission and muscular tone in the sphincter muscle of the bovine iris.
Specific and Unspecific Removal of Circulating Noradrenaline in Pulmonary and Systemic Vascular Beds in Man
Authors: Stjärne Lennart , Kaijser Lennart , Mathé Aleksander , Birke Gunnar 
Published: December 2008

AbstractIn order to study the extent and degree of specificity of the removal of circulating noradrenaline (NA) from the blood stream, during a single passage through the vascular beds of the lungs and of the forearm musculature of unanaesthetized, healthy young men, the following radiometric method was used: A mixture of3H‐NA with14C‐inulin and125I‐labelled human serum albumin was injected proximally to the bed under study; six serial blood samples were drawn distally to it, with about 15 s interval, and the disappearance of3H‐NA relatively to that of14C‐inulin and125I‐albumin was determined.3H‐NA was found to be removed from the blood stream in both these vascular beds. However, in the forearm the removal of3H‐NA was much greater, and apparently to a large extent due to specific trapping in the tissues, since the clearance of3H‐NA over the vascular bed of the forearm markedly exceeded that of 14C‐inulin. During passage through the lungs removal of3H‐NA was less marked, and apparently largely unspecific, since it was initially essentially equal to that of14C‐inulin. This suggests that removal of circulating ergones of small molecular sire, from the blood stream passing through the lungs, may occur initially by unspecific filtration/diffusion. Their subsequent fate would depend on whether the extraluminal tissues, supplied by the lung circulation, possess specific mechanisms for concentrating and/or inactivating each particular compound.
Rat Liver Mitochondrial Enzyme Activities in Hypoxia
Authors: Kinnula Vuokko L. 
Published: December 2008

AbstractRat liver mitochondrial enzyme activities were measured after exposing the animals to the atmospheric pressure of 380 mm Hg for 5 h and 14 days. Succinate dehydrogenase and succinate oxidase activities increased significantly during the hypoxic period of 14 days. No change was observed in cytochrome oxidase activity. Malate dehydrogenase and glutamate dehydrogenase activities increased somewhat, but not significantly. The efficiency of oxidative phosphorylation (the ADP: O ratio) in the isolated mitochondria remained unchanged. The exact mitochondrial protein values showed a 15% decrease as compared with the control group. The concentrations of cytochromes did not change significantly in the hypoxic group. During the short hypoxic period succinate dehydrogenase, succinate oxidase and cytochrome oxidase activities increased as compared with those in the control group.
Radioactively Labelled Microspheres in Regional Cerebral Blood Flow Determinations A study on monkeys with 15 and 35 μm spheres
Authors: Alm Albert 
Published: December 2008

Abstract15 μm and 35 μm radioactive microspheres, differently labelled, were used simultaneously for rCBF‐determinations in monkeys. Flow values calculated from data for 35 μm spheres were 27±7 g/min per 100 g higher for grey matter and 10±3 g/min per 100 g lower for white matter than flow values calculated from 15 μm spheres, while both sphere sizes resulted in similar values for the choroid plexus. A large number of 35 μm spheres were trapped in extracerebral pial arterioles. It is concluded that entrapment in relatively large arterioles of the 35 μm spheres explains the differences in flow values, and that this invalidates the use of 35 μm spheres, and larger, in rCBF‐determinations.
Cholinergic Receptors at Denervated Mammalian Motor End‐Plates
Authors: Frank Erik , Gautvik Kaare , Sommerschild Henrik 
Published: December 2008

AbstractThe number of acetylcholine receptors at normal and denervated end‐plates in rat soleus muscles was studied using the binding of [125I] α‐bungarotoxin as a quantitative assay. Normal end‐plates bound several thousand times as much toxin as equal areas of extra‐synaptic muscle membrane. After short‐term denervation (up to 2.4 weeks) the extrajunctional binding increased, but there was no change in specific binding to the motor end‐plate. Denervation for longer periods (up to 7 weeks) reduced binding sites at the end‐plate by up to 60–70%. Direct electrical stimulation of these muscles for the entire period of denervation did not prevent the loss of junctional binding sites even though it was adequate to abolish the increase in extrajunctional toxin binding. In contrast, denervated end‐plates on muscle fibres cross‐innervated by a Foreign nerve at a distant location continued to bind normal amounts of toxin for over four months.
The Pulmonary Vasoconstrictor Response to Hypoxia: Effects of Inhibitors of Prostaglandin Biosynthesis
Authors: Vaage J. , Bjertnæs L. , Hauge A. 
Published: December 2008

AbstractThe main purpose of the present work was to determine whether prostaglandins (PGs) synthetised in the lungs mediate the vasoconstrictor response to acute alveolar hypoxia. Isolated and ventilated lungs of rats were perfused at 37°C with homologous blood at constant‐volume, pulsatile inflow, and pressor responses to 3 min periods of standardized ventilation hypoxia recorded. Indomethacin, sodium meclofenamate and acetylsalicylic acid (all 100 μg/ml), which are potent inhibitors of PG biosynthesis, did not reduce the hypoxic vasoconstrictor response. Sometimes they even enhanced this response. We conclude that PGs do not mediate the hypoxia‐induced vasoconstriction. We suggest that vasodilatory PGs might act to reduce and modify pulmonary arterial hypertension due to hypoxia.
Reflexogenic Contraction of the Ileo‐Cecal Sphincter in the Cat Following Small or Large Intestinal Distension
Authors: Pahlin P.‐E. , Kewenter J. 
Published: December 2008

AbstractThe effect of distension of a small or large intestinal loop on the ileo‐cecal sphincter (ICS) in the cat was studied with a flow‐recording technique. Distension of a small or large intestinal loop, isolated from the adjacent intestine, but with its mesenteric vascular and nervous supply intact, elicited a contraction of the ICS concomitant with an inhibition of the adjacent large and small intestinal motility. Vagal and pelvic nerve section did not affect the response to distension of the ICS nor exclusion of the adrenal glands from the circulation. The sphincter reflex could be entirely or almost entirely eliminated by cutting both the splanchnic and lumbar colonic nerves, but not one or the other. Spinal anesthesia blocked the reflex response indicating a spinal reflex arc. The reflex persisted after atropine and propranolol, while both guanethidine and phenoxybenzamine completely abolished the reflex contraction of the sphincter.The present results indicate that the excitatory intestino‐ileo‐cecal sphincteric reflex is a spinal reflex with the main afferent and/or efferent fibres located within the major splanchnic and lumbar colonic nerves. The excitatory motor response in the sphincter is adrenergic and mediated viaα‐receptors.
Cardiopulmonary Blood Volumes at Rest and during Muscular Exercise Measured by 113mIn Radiocardiography
Authors: Kuikka J. , Psc>yörälä T. , Lehtovirta P. , Rekonen A. 
Published: December 2008

AbstractCardiac output, stroke volume, right heart and left heart blood volume, pulmonary blood volume and pulmonary mean time were measured at rest and during muscular exercise in 14 healthy subjects in the supine position. The method used was 113mIn radiocardiography measured precordially with a single detector. The results were analyzed with a minicomputer by a modified gamma function fitting method. The increase in cardiac output during exercise was 140 per cent (p < 0.001). The stroke volume increased 15 per cent (p < 0.05) in subjects with heart rates < 160 beats/min, and decreased in subjects with heart rates ≥ 160 beats/min. The right heart blood volume decreased from 115 ml/m2 to 105 ml/m2 (5 per cent; p>0.1) and the left heart blood volume decreased from 115 ml/m2 to 105 ml/m2 (5 per cent; p < 0.01). The total heart blood volume thus decreased from 120 ml/m2 to 110 ml/m2 (5 per cent; p < 0.01). The pulmonary blood volume showed a corresponding increase from 250 ml/m2 to 280 ml/m2 (12 per cent; p < 0.005), and the cardiopulmonary blood volume did not markedly change (485 ml/m2 and 495 ml/m2). Pulmonary mean time decreased from 5.0 s to 2.4 s (52 per cent; p < 0.001).
Motor Unit Responses in the Lateral Rectus Muscle of the Cat: Intracellular Current Injection of Abducens Nucleus Neurons
Authors: Goldberg S. J. , Lennerstrand G. , Hull C. D. 
Published: December 2008

AbstractSingle motor units of the cat's lateral rectus muscle were activated with short intracellular current pulses delivered through an intracellular micropipette penetrating a single motoneuron, and the mechanical responses in the muscle were recorded. Lateral rectus unit responses fell within the same range as those obtained earlier with extracellular stimulation of inferior oblique units, confirming that in the latter case single and not multiple motor units had been studied. It was also found that both fast and slow contracting muscle units were connected to fast conducting, large size motoneurons. The organization of motor unit recruitment in eye movements would thus seem different from the recruitment pattern in limb muscles.Intracellular stimulation of abducens nucleus “interneurons” did not initiate contractions at the ipsilateral lateral rectus muscle. These “interneurons”, therefore, did not appear to have excitatory inputs to the abducens motoneurons, but may be involved in relaying information to the other extraocular muscle nuclei or to other brain centers.