bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Effect of Stimulation of the Cervical Sympathetic Chain on Retinal Oxygen Tension and on Uveal, Retinal and Cerebral Blood Flow in Cats
Authors: Alm Albert , Bill Anders 
Published: December 2008

AbstractThe effects of stimulation of the cervical sympathetic chain on blood flow through the retina, the different parts of the uvea, different parts of the brain and some other tissues were studied in cats. 5 Hz reduced the oxygen tension in the vitreous body close to the retina in 5 expts. of 6. 15 μm labelled microspheres were used for quantitative determinations of blood flow. Unilateral stimulation at 10 Hz was performed for 1 min in 9 normocapnic and in 4 hypercapnic cats and for 15–30 min in 5 normocapnic cats. The results suggest that blood ffow through the innermost layers of the retina is influenced by sympathetic stimulation. The vascular resistance within the uvea was much increased in all three groups with no indications for “autoregulatory escape”. The effect was most pronounced in the ciliary processes and least in the ciliary muscle. “Autoregulatory escape” was seen in the parotid gland, the tongue and the masseter muscle, where 1 min stimulation caused mean reductions in blood flow by 82–99% compared to 6–56% after 15–30 min stimulation. Cerebral blood flow showed no statistically significant reductions in either group indicating a quantitatively minor role for the sympathetics in regulation of total cerebral blood flow in cats.
Influence of Fixation on Physiological Properties of Frog Gastric Mucosa
Authors: Helander Herbert F. , Rehm Warren S. , Sanders Sue S. 
Published: December 2008

AbstractFunctional properties of the in vitro frog gastric mucosa were studied during fixation with glutaraldehyde (G4) or OsO4. The acid secretory rate dropped quickly and was completely absolished within 5–15 min. When fixative was added to either the serosal or mucosal surface of the mucosa the potential difference decreased rapidly within the first minute and frequently became temporarily inverted. The electrical resistance changes almost always included an initial drop. With GA added to either side and with OsO4 added to the serosal side the resistance then rose to values above the controls, again returning to very low values after intervals usually between 15 min and 2 h. With OsO4 added to the mucosal side the resistance decreased rapidly to low levels and did not recover. The selective permeability of the nutrient membrane of K+ over Na‐ was decreased within 5 to 10 min, but was not abolished until about 35 min after the addition of the fixatives, at which time the mucosal resistance was still high. It is concluded that the ion‐conducting pathways in the plasma membranes are greatly changed by the fixatives, which should be taken into consideration when interpreting electron micro‐graphs.
Noradrenaline Depletion in the Kidney Vessels in Experimental Ascites
Authors: Penttilä Antti , Tallqvist Gustav 
Published: December 2008

AbstractNoradrenaline depletion in experimental ascites originally observed by the authors could hypothetically be attributed to the ascites formation or to the tumour by which the ascites wits induced. Therefore mice were injected intraperitoneally or subcutaneously with Ehrlich ascites carcinoma. Noradrenaline was assayed histochemically and biochemically in the kidney at various times after injection. Mice with intraperitoneal tumour and ascites had significantly less noradrenaline than controls both histochemically and biochemically. Mice with subcutaneous tumour (without ascites) had depletion that was significant, by biochemical tests, only on the iifth and seventh days but was not detectable histochemically. It is concluded that noradrenaline depletion seems to be associated with the tumour growth per se but more particularly with ascites formation.
Renal Medullary Red Cell and Plasma Flow as Studied with Labelled Indicators and Internal Detection
Authors: Wolgast Mats 
Published: December 2008

AbstractRegional renal medullary red cell and plasma flow has been investigated on 8 dogs using 32‐P labelled red cells and plasma and detection with small needle‐shaped semiconductor detectors put into the parenchyma. The transit times were determined by dividing the area with the height of the indicator‐dilution curves obtained after slug injections of alternatively labelled red cells and labelled plasma into the renal artery. Regional red cell volume was obtained from intrarenal equilibrium activity. The plasma volumes relative to the red cell volumes was determined by comparing the areas of the two indicator‐dilution curves. Whole blood flow was then estimated at 2 ml/min and g tissue in the outer zone continuously decreasing to values around 0.5 ml/rnin and g tissue in the inner parts of the inner zone. The hematocrit in vasa recta blood (denoting the ratio between the flow of red cells to the flow of whole blood) was in the outer zone 85% of that in arterial blood, successively decreasing to about 50% in the inner parts of the renal medulla.
Proximal Luminal Diameters and Cell Volume in Rats Anesthetized with Inactin and Amytal
Authors: Elmer M. , ØTergaard KRISTENSEN L. , Leyssac P. P. 
Published: December 2008

AbstractLuminal diameters and cellular area oi cross‐sectioned, superficial proximal convolutions were measured in freeze‐dryed cryo‐sections of normal, non‐diuretic rat kidneys instantly frozen with liquid nitrogen at the end of clearance‐and micropuncture experiments. Two series were investigated; in one series rats were anesthetized with the thiobarbiturate Inactin; in the other series the oxybarbiturate Amytal was used as anesthetic; all other factors were equal. In rats anesthetized with Amytal proximal luminal radius was about 14 μm independent of the inulin clearance (ClIN) over a range between 0.57 and 1.61 ml · min‐1· g KW‐1. Proximal cellular volume, as estimated from the cross‐sectional area, was also independent of the clearance value. In the Inactin series proximal luminal radius correlated with ClIN(p ˜ 0.018) The luminal radius was depressed from a value of 14.5 μm at a ClINabout 1.40 ml · min‐1g KW‐1to 12.0 μm at a ClINof about 0.50 ml · min‐1g KW‐1, a value significantly less than that of the Amytal series. Although the cross‐sectional cellular area tended to increase at low clearance values in the Inactin series, the increase was not statistically significant. The data do not exclude, however, the existence of an inverse relationship between cellular volume and ClIN
Effects of Insulin and Testosterone on Glycogen Synthesis and Glycogen Synthetase Activity in Rat Levator Ani Muscle
Authors: Adolfsson Sten 
Published: December 2008

AbstractThe temporal relationships for hormonal stimulation of glycogen synthesis are not clarified. In the present study glycogen synthesis and the activation of the rate‐limiting glycogen synthetase enzyme (EC 2.4.1.11) were investigated in levator ani muscles from prepubertal male rats during insulin stimulation in vitro for 5–240 min and testosterone stimulation in vivo for 4–36 h. For both hormones, glycogen content was gradually increased to a level of 8.5–9.0 mglg tissue. An activation of the synthetase enzyme by means of an increase of its I‐form was found after only 5 min of insulin stimulation. The increase in I‐form was continuously reduced and reached control level after 150 min of incubation. For testosterone, the I‐form was steadily increased 6–16 h after injection of the hormone. The incorporation of glucose‐14C into glycogen was increased in both studies even when the I‐form was no longer increased. The level of glucose‐6‐phosphate was aiso measured and the results suggest an activation of the synthetase enzyme by changes in the concentration of this metabolite during hormonal stimulation. It is concluded that the length of stimulation is of importance for the stimulation of muscle glycogen synthesis by insulin and testosterone.
Effects of Severe Systemic Hypoxia on Myocardial Energy Metabolism
Authors: Fellenius E. , Samuelsson R. 
Published: December 2008

AbstractBy the use of freeze‐clamp technique, simultaneous tissue samples were taken from the right atrial and the right ventricular muscle of the working heart in anesthetized dogs during a hypoxia‐recovery cycle consisting of 4 min of severe, systemic hypoxia followed by a period of recovery of equal duration. In order to study the energy metabolism of the two parts of the heart, the tissue samples were analyzed with respect to their content of creatinephosphate, adenine nucleotides, pyruvate, lactate, dihydroxyacetonephosphate, α‐glycerophosphate and malate. During aerobic, controlled ventilation, the ventricular tissue was found to contain higher concentrations of high‐energy phosphate compounds than the atrial tissue. During the period of hypoxia, the atrial and ventricular tissue contents of creatinephosphate were reduced to about 10% whereas ATP was reduced merely to about 70% of the control values. The rate of the anaerobic glycolysis was found to proceed more rapidly in the ventricular muscle, thereby indicating a higher rate of energy metabolism, than in the atrial muscle.
Effects of Severe Systemic Hypoxia on Myocardial Excitation
Authors: Samuelsson R. 
Published: December 2008

AbstractIn anesthetized dogs, monophasic action potentials from the right atrium and the right ventricle were recorded by an intracardiac suction electrode technique, together with the electrocardiogram (standard lead II). The animals were subjected by ventilation with 100% nitrogen to periods of severe, systemic hypoxia. The separate effects of myocardial oxygen deficiency and increased autonomic influence on the myocardial excitation were studied, using animals with (1) intact autonomic innervation of the heart, (2) parasympathetically denervated hearts and (3) parasympathetically and sympathetically denervated hearts. During severe, systemic hypoxia the parasympathetic influence predominated over the sympathetic and induced a pronounced shortening of the duration of the atrial monophasic action potential whereas the increased sympathetic activity induced no alteration of the duration of the ventricular monophasic action potential. The myocardial oxygen deficiency induced a shortening of the duration of the atrial monophasic action potential which appeared earlier than that of the duration of the ventricular monophasic action potential when the autonomic influences were excluded. During the recovery from myocardial oxygen deficiency, the duration of the atrial monophasic action potential was normalized earlier than that of the ventricular monophasic action potential. Pronounced ST‐segment and T‐wave elevations in the ECG were in general recorded when the period of severe, systemic hypoxia exceeded 2 min.
Vago‐vagal Gastro‐gastric Relaxation in the Cat
Authors: Abrahamsson Hasse , Jansson Gunnar 
Published: December 2008

AbstractIn anesthetized cats electric afferent stimulation of nerve branches emanating from the gastric corpus region promptly elicited reflex gastric relaxation. The response was not blocked by atropine, guanethidine or cervical spinal cord transection but was abolished by cervical vagotomy, showing that the vagal “relaxatory” fibres to the stomach mediate this reflex effect. Transient distension of the stomach produced a long‐lasting gastric relaxation with similar characteristics as that obtained by the mentioned afferent electric stimulation. By vagal blockade in atropinized cats it was shown that the vagal nerves exerted no or only slight relaxatory effects if the stomach was only slightly filled, hut then had a profound relaxatory effect when the stomach was moderately or greatly filled. It is concluded that a vago‐vagal gastro‐gastric relaxatory reflex exists where the vagal non‐adrenergic relaxatory fibres serve as the efferent link. The reflex can be activated from gastric mechanoreceptors responding to distension and is suggested to be involved in the regulation of receptive relaxation in gastric filling.
Effect of Histamine Loading on the Metabolism of 14C‐Histarnine, Administered Intravenously or Orally, in Domestic Animals (Goat and Pig)
Authors: Eliassen Knut Arnet 
Published: December 2008

AbstractIsotope dilution technique has been used to examine the effect of histamine loading on the metabolism of orally and parenterally administered 14C‐histamine. 3% and 45% of the radio‐activity was recovered in the urine of goats and pigs, respectively, when only 14C‐histamine was given orally. In goats the radioactivity was mostly present as unidentified metabolites. In goats, oral loading with 0.9–1.2 g histamine increased the fraction excreted as ImAA on an average from about 5% to 34% whereas the amount of unidentified metabolites was reduced. Independent of the dose given about 30% of orally administered radioactivity was excreted as 14CO2. In pigs a moderate increase in 14‐imidazoleacetic acid was observed after oral histamine loading. In contrast to i.v. administered histamine, orally administered histamine was partly excreted as 14C‐conjugated histamine in the pig. In pigs and goats neither oral nor i.v. histamine loading seemed to have any effect on the fraction excreted in urine as 14C‐histamine. The only significant effect on histamine catabolism of i.v. loading of histamine was a reduction of the fraction excreted as 14C‐1.4‐MeHi. However, such loading of histamine in pigs seems to liberate histamine and/or histamine metabolites, since the increments in urinary histamine and histamine metaboiites exceeded the administered dose.
On the Elimination of Transfused Heparin‐Induced Diamine Oxidase (DAO) Activity in Rabbits
Authors: Hansson R. , Thysell H. 
Published: December 2008

AbstractLymph or blood plasma, rich in diamine oxidase (DAO; EC 1.4.3.6.) activity was obtained from donor rabbits, after i.v. injection of heparin. The lymph or, after heparin neutralization, the blood serum was injected into recipient rabbits, and the elimination of the transfused DAO activity was studied. Analogously to earlier findings in man, the elimination rate of transfused DAO activity was several times more rapid than is indicated by the apparent rate of return to normal levels in rabbits, after heparin‐induced increase in blood plasma DAO activity. Furthermore, our findings indicate the possibility of 2 different components of the elimination of transfused postheparin rabbit DAO activity, somewhat contrasting to the findings in man.
Effect of Organ Removal or Damage on the Heparin‐Induced Diamine Oxidase (DAO) Response in Rat and Rabbit
Authors: Hansson R. , Thysell H. 
Published: December 2008

AbstractThe postheparin DAO increase in blood plasma has been shown to depend on intact intestines in rat and rabbit. Our findings indicate, however, that sources of mobilizable DAO may be found also outside the small intestine in these species. In the rat, after partial portal stricture for a week. hepatectomy was followed by an intense and rather sustained post‐heparin DAO increase, as compared to normal, or shamoperated, rats.
The Liver‐like Anion Transport System in Rabbit Kidney, Uvea and Choroid Plexus. I. Selectivity of Some Inhibitors, Direction of Transport, Possible Physiological Substrates
Authors: Bárány Ernst H. 
Published: December 2008

AbstractAccumulation of o‐iodohippurate and iodipamidein vitrooccurs by 2 overlapping systems, the liver‐like L‐, and H‐, the classical PAH‐transporting one. Selectivity of competitors is compared by measuring depression of simultaneous uptake of o‐iodohippurate and iodipamide. Results (kidney cortex): o‐Iodohippurate has similar H‐selectivity as hippurate while iodipamide is much more L‐selective than its non‐iodinated parent. Ioglycamic acid is at least as L‐selective as iodipamide. Rabbit bladder bile is L‐selective, rabbit and human urine H‐selective. Probenecid is somewhat H‐selective, its diethyl homologue more H‐selective, its dibutyl homologue more L‐selective. Phenol red, furosemide, ethacrynic acid, sulfobromophthalein, phenolphthalein and iopanoic acid are rather unselective. Selectivity of probenecid, hippurate and iodipamide is not influenced by incubation time. Cephaloridinein vitrois somewhat H‐selective but inhibits both systems in kidney, choroid plexus and uvea.In vivo200 mg/kg causes tubular damage which depresses the H‐more than the L‐system. Choroid plexus and ciliary processes are undamaged. The two systems L‐and H‐seem to have the same direction of transport, from aqueous humour and CSF to the blood and from the blood into the urine. The H‐system mainly deals with candidates for urinary and the L‐system with candidates for biliary excretion.
Vomiting and Reflex Vagal Relaxation of the Stomach Elicited from Heart Receptors in the Cat
Authors: Abrahamsson Hasse , Thorén Peter 
Published: December 2008

AbstractThe effect of afferent stimulation of the vagal cardiac nerves on gastric motility, heart rate and arterial blood pressure was studied in cats. Electric stimulation of the right cardiac nerve elicited, beside bradycardia and hypotension, a prompt and pronounced gastric relaxation and, after a latency, somatomotor vomiting movements.—Frequency‐response curves showed maximal circulatory effects already around 6 Hz while the curve for gastric relaxatory response was less steep. Frequent retching was observed at stimulations of 10 Hz or more.—The gastric relaxation upon afferent cardiac nerve stimulation was abolished by sectioning the right vagus caudad to the cardiac nerve and the left vagus in the neck, showing that vagal efferents mediated the gastric relaxation. The gastric response persisted after atropine and guanethidine ad was mimicked by reflex activation of the vagal “relaxatory” fibres to the stomach by esophageal distension. Intrapericardial nicotine and coronary artery occlusion also activated the described gastric reflex.—It is concluded that vomiting can be elicited by thin vagal cardiac afferents, probably of ventricular origin. Gastric relaxation, mediated by the vagal non‐adrenergic relaxatory fibres, constitute part of this vomiting response, as when vomiting is induced by apomorphine.
Recurrent Inhibition from Motor Axon Collaterals of Ventral Spinocerebellar Tract Neurones
Authors: Lindström S. , Schomburg E. D. 
Published: December 2008

AbstractRecurrent inhibition from motor axon collaterals was searched for in intracellularly recorded ventral spinocerebellar tract (VSCT) neurones in the cat. A small proportion of the investigated cells received inhibition on antidromic stimulation of ventral roots. The IPSP was evoked by a‐fibres, had a segmental latency indicating a disynaptic linkage from motor axon collaterals and a duration of about 50 ms. The inhibited cells received monosynaptic excitation from group Ia muscle spindle afferents. The inhibition could be demonstrated also on the VSCT mass discharge evoked by stimulation of Ia afferents. The ventral roots, giving rise to the inhibition in a given VSCT cell, were the same as the ventral roots which give recurrent inhibition in a‐motoneurones and Ia inhibitory interneurones excited by Ia afferents of the same muscle as the VSCT cell. The results indicate that Renshaw cells, terminating on a‐motoneurones and Ia inhibitory interneurones, also send collaterals to some VSCT neurones. This finding strongly supports the idea that the VSCT relays information about the transmission in intemeuronal inhibitory reflex pathways to motoneurones (Lundberg 1971).
Drug Effects on Pre‐and Post‐branchial Blood Pressure and Heart Rate in a Free‐swimming Marine Teleost, Gadus morhua1
Authors: Helgason Sigurdur St. , Nilsson Stefan 
Published: December 2008

AbstractDrug effects on pre‐and post‐branchial blood pressure and heart rate have been simultaneously and continuously registrated in free‐swimming cod(Gadus morhua).Adrenaline, noradrenaline and phenylephrine increased blood pressure, presumably by increasing systemic vascular resistance by alpha adrenergic stimulation. The heart rate was decreased by the same drugs, obviously by a baro‐receptor reflex, with the efferent inhibitory cholinergic fibres running in the vagus nerve. Yohimbine decreased the blood pressure and blocked the effect of adrenaline. The drop in blood pressure may be due to blockade of a normally acting vaso‐constrictor effect on the systemic vessels. Pre‐and post‐branchial blood pressure was reduced by isoprenaline, and this effect was reversed by propranolol, suggesting presence of adrenergic beta‐receptors in the systemic vascular bed. Propranolol also caused a drop in heart rate and post‐branchial blood pressure, while the pre‐branchial blood pressure was increased. This again could be due to abolishment of a normally acting adrenergic influence on the heart and branchial vessels.
Effect of Training with Eccentric Muscle Contractions on Skeletal Muscle Metabolites
Authors: Bonde‐Petersen Flemming , Henriksson Jan , Knuttgen Howard G. 
Published: December 2008

AbstractThe effect of training with eccentric contractions on skeletal muscle metabolism was in‐vestigated with human subjects engaged in cycling exercise. Experiments involving extended (30 min) exercise at high relative intensities were performed before and after a 5‐week period of training (25–30 min per day, 22 days). Muscle biopsies (lateral portion of m. quadriceps femoris) were taken at rest, after 4 min exercise, and termination of exercise. Expired air was collected periodically for determination of respiratory exchange. Vo 2 and heart rate were lowered by training (e.g., after 26 min of exercise: from an average of 0.96 to 0.74 1 × m‐l and 115 to 96 beats × min‐1, respectively). Muscle metabolite concentration evidenced no significant changes but respiratory exchange ratio (R) was decreased (after 10 and 26 min, from an average of 0.85 to 0.80 in both instances). Metabolic determinations offered no explanation for the lowered 02 cost of exercise nor evidence for or against the hypothesis that the muscles utilize the mechanical energy recived during eccentric exercise.
Circulatory Control via Vagal Afferents VI. The bleeding bradycardia in the rat, its elicitation and relation to the release of vasopressin
Authors: SJÖSTRAND TORGNY 
Published: December 2008

AbstractSjöstrand, T. Circulatory control via vagal afferents. VI. The bleeding bradycardia in the rat, its elicitation and relation to the release of vasopressin. Acta physiol. scand. 1973. 89. 39–50.Bradycardia appears regularly in Sprague‐Dawley rats on arterial hemorrhage. It is usually preceded by an increase of the heart rate of varying duration. On an average the bradycardia starts 21s after the fall in arterial pressure. On reinfusion the bradycardia disappears during 10–20 min following a varying course. Compression of the inferior caval vein provokes bradycardia which appears and disappears similarly but starts earlier in relation to the pressure fall. If blood or saline is intravenously infused simultaneously with the hemorrhage, the bradycardia starts later and is less pronounced in relation to the fall in arterial pressure. The bradycardia is inhibited by hypophysectomy, hydration and infusion of small amounts of ethyl alcohol through the carotid artery. A similar bradycardia may be provoked by intra‐carotid infusion of vasopressin at maintained arterial pressure.It is concluded that the bleeding bradycardia is elicited by receptors on the low pressure side stimulated by a decrease of the venous return or central blood volume and is a part of a reflex control of the blood volume and distribution. The release of vasopressin is stimulated through vagal afferents and, by local transmission, exerts an excitatory effect on the depressor area in the hypothalamus. The significance of the deduced vasopressin releasing reflex under normal and pathological conditions is discussed.