bluuebunny/crossref_metadata_2025_split huggingface dataset:
The CSF/Blood Potential in Sustained Acid‐Base Changes in the Rat. With Calculations of Electrochemical Potential Differences for H+and HCO‐3
Authors: Kaällquist Å. 
Published: December 2008

AbstractThe electrical D.C. potential difference between cisternal cerebrospinal fluid and external jugular blood was measured in rats during sustained acid‐base changes. One group, serving as a control series, was given an artificial extracellular fluid i.p., while two other groups were made acidotic or alkalotic by means of i.p. injections of NH4Cl or NaHCO3 solutions. In the last two groups NH4Cl or NaHCO3 was given, but Con was simultaneously administered so as to keep either the plasma bicarbonate or the plasma pH constant. In all groups the CSF/ plasma potential was permanently changed in relation to the arterial plasma pH, but there was a larger potential change in alkalosis (about 50 mV/pH unit) than in acidosis (about 30 mV/pH unit). Calculations of electrochemical potential differences for H+and HCO3‐between CSF and plasma showed no significant differences in nonrespiratory acidosis and alkalosis but significant increases in hypercapnia. The results do not support the theory that an active H+transport regulates the CSF pH to constancy.
Neurotransmitter Releasing Effects of Two Quaternary Nicotine Analogues
Authors: von Euler U. S. , Haclid F. , Hedqvist P. , Motelica I. 
Published: December 2008

AbstractTwo nicotine analogues, im‐monomethylnicotinium bromide (IMN) and 1–methyl‐3–(pyrro‐lidinomethyl)‐pyridinium bromide (MPP) have been studied with regard to their catechol‐amine releasing effects in the guinea pig and the rat. In doses of 10–30 mg/kg intraperitoneally IMN decreased the noradrenaline (NA) content of the guinea pig heart. In larger doses, up to 300 mg/kg, both substances caused 80–90 per cent NA depletion of the heart but not in the brain. Maximal effect was reached in 6–12 hn. In the decentralized sub‐maxillary gland the NA content decreased more slowly after IMN than in the normal gland. 6 hrs after sympathetic denervation of the gland the NA content was unchanged in the controls but fell to about one third of the normal after IMN, indicating a peripheral effect. Cold exposure (+2°) for 1 1/2 to 30 hrs did not increase the NA depleting effect of IMN in the rat heart. Catecholamine and vanilmandelic acid excretion in urine of the rat were not significantly increased after IMN and MPP even in doses of 300 mg/kg.It is concluded that the compounds release NA from the nerve terminals and that the release is enhanced by the normal nerve activity. Some reasons for the slow action are discussed.
Uptake of Some Catecholamines and Their Precursors into Neurons of the Rat Ciliary Ganglion
Authors: Ehinger B. , Falck B. 
Published: December 2008

AbstractNo adrenergic perikarya and only vascular adrenergic terminals were found in ciliary ganglia of normal rats, cats, guinea‐pigs, goats and monkeys, but adrenergic neurons occurred in animals that died under severe stress. Small, intensely fluorescent cells were irregularly observed in rats and cats, and in a cebus monkey. In rats, Nialamide and L‐DOPA (but not D‐DOPA) induced specific fluorescence in certain neurons, which was prevented by dopa decarboxylase inhibition. a‐Methyldopamine and α‐methyldopa also induced fluorescence, but less effectively. The increase in fluorescence in the ciliary ganglion was always less than in the superior cervical ganglion. Cervical sympathectomy did not influence the appearance of fluorescence in the ciliary ganglion. The results were interpreted to indicate that the ciliary ganglion contains a system of neurons which are presumably intraganglionic, do not normally contain catecholamines in sufficient concentration to make them readily demonstrable, presumably contain dopa decarboxylase and monoamine oxidase, and can take up certain amines. These neurons are perhaps ordinary adrenergic nerves operating with an unusually low concentration of noradrenaline, but it cannot be excluded that they have a transmitter substance that is not noradrenaline.
Left Ventricular Pressure and Maximum Rate of Pressure Rise as Determinants of Myocardial Oxygen Consumption during Hemorrhagic Hypotension in Dogs
Authors: Bugge‐Asperheim B. , Kjekshus J. 
Published: December 2008

AbstractThe influence of systolic left ventricular pressure (SLVP) and maxjmum rate of rise of left ventri cular pressure (dP/dt) on left myocardial oxygen consumption (MVO2) has been studied in intact, anesthetized dogs. Noradrenaline and angiotensin were infused in animals which had been bled to a mean aortic blood pressure of 50–60 mm Hg. End‐diastolic volume was reduced by bleecling, but remained fairly constant during the pressure changes caused by the noradrenaline and angio tensin infusions. Wall tension could therefore be regarded as proportional to SLVP.During noradrenaline infusions, which were adjusted so as to increase mean aortic blood pressure to 130 mm Hg, SLVP, dP/dt and MVO2 increased. An unchanged relationship remained between dP/dt and MVO2 after a‐adrenergic receptor blockade when SLVP did not rise. During infusion of angiotensin there was a marked elevation of SLVP, but only small increases in MVO2 and dP/dt.On the basis of the changes in MVO2, SLVP and dP/dt, it was shown that the contribution to an increase in MVO, of a rise in SLVP is accounted for By the concomitant increase in dP/dt.
Effects of Hemorrhagic Shock and Treatment with Hypothermia on the Potassium Content and Transport of Single Mammalian Skeletal Muscle Cells
Authors: Haljamäe Hengo 
Published: December 2008

AbstractThe effect of in vivo hemorrhagic shock and its treatment with hypothermia was studied by following the temporal pattern of intracellular potassium content in single skeletal muscle fibres during in vitro incubation. For the control cells isolated before the different experi mental procedures were instituted, reproducible changes in potassium content were observed during the period of incubation. The potassium content of cells isolated shortly after the taking of the biopsy was somewhat lower than of cells isolated after 10 min of incubation. After 10 to 15 min of incubation a marked loss of cellular potassium was seen, followed by a period of active reaccumulation. After hemorrhagic shock under normothermal conditions the potassium content of the cells was markedly lower and no active cellular potassium reaccumulation was obtained during prolonged incubation. Hemorrhagic shock treated with hypothermia lowered the initial pptassium content somewhat but both the periods of cellular potassium loss and active reaceumulation were seen. Hypothermia alone only slightly modified potassium transport during the first 10 to 15 min of in vitro incubation.The results are discussed from the standpoint of cellular metabolism and high‐energy phosphate production with special reference to the exchange of substances between body com partments under the diffrent experimental conditions.
Effect of the C‐Terminal Octapeptide of Cholecystokinin on Guinea Pig Ileum and Gall‐Bladder in vitro
Authors: Hedner Pavo 
Published: December 2008

AbstractThe C‐terminal octapeptide of cholecystokinin shares the pharmacological properties of the original molecule. Both seem to act directly on the smooth muscle cell of the gall‐bladder but indirectly via a nervous pathway in the ileum. Both reduce the resistance of the choledocho‐duodenal junction. This pharmacological profile is characteristic for a group of substances which besides cholecystokinin and its C‐terminal octapeptide also includes gastrin, pentagastrin and caerulein. There is a close chemical relationship between these substances, e.g. they all have the same C‐terminal tetrapeptide.Effective doses for the octapeptide were 0.1–0.5 ng/ml in vitro. Its molar activity in the gall‐bladder and ileum is comparable to that of caerulein and about 3 times that of cholecysto kinin and 1000 times that of pentagastrin.Besides the heterologous caerulein the C‐terminal octapeptide of cholecystokinin appears as the most active gall‐bladder contracting agent known at present, with a molar activity about 100 times that of acetylcholine, histamine or bradykinin.
Effects of Noradrenaline upon Cerebrocortical Activity in Asphyxiated Newborn Rabbits
Authors: Boëthius Jörgen , Brunclin Tomas , Persson Nils‐Åke 
Published: December 2008

AbstractThe asphyxia resistance of the direct cortical response (DCR) and the electrocorticogram (ECG) was determined in noradrenaline treated and untreated newborn rabbits. The resistance of the untreated animals was similar to what has previously been found for the adult, the DCR being blocked within 3 1/2 min and the ECG within 2 min of asphyxia. After the ad ministration of noradrenaline the DCR became more resistant to asphyxia and could be evoked for 8–17 min. The ECG was not sustained by noradrenaline, and was blocked within 2 min of asphyxia as it was in the untreated animals.An increased ability of the DCR to withstand asphyxia has been described for the fetus. In view of the above mentioned effect of noradrenaline, it was proposed that this resistance of the fetal DCR to asphyxia is due to the fact that in the fetus asphyxia stimulates the release of noradrenaline from the preaortal paraganglia and the adrenal medulla. Possible mechanisms whereby the increased resistance of the DCR could be effected by noradrenaline were discussed.
Disappearance of Serum Insulin in Obese‐Hyperglycemic Mice
Authors: Coore Haldane G. , Westman Sighild 
Published: December 2008

AbstractThe disappearance from serum of i.v. injected insulin has been studied in obese‐hyperglycemic and lean mice. Groups of mice were given either a high dose, 600 U bovine insulin/kg b.w., or a tracer dose 125I‐labelled insulin. The serum content of immunoreactive insulin or anti body bound radioactive insulin was measured at intervals. No difference in disappearance rate was noted between the obese and lean mice after the high insulin dose. When studied under more physiological conditions with a tracer dose, it was found that the rate of insulin dis appearance from serum was greater in the obese animals. These finclings are discussed against the background of previous observations of increased resistance to insulin hypoglycemia in obese mice and an increased insulin degracling activity of adipose tissue homogenates from such mice.
Studies of the Damped Oscillatory Response of the Auditory Frequency Analyzer
Authors: Møller Aage R. 
Published: December 2008

AbstractThe temporal characteristics (system impulse response) of the peripheral, auditory spectrum analyzer, up to the level of the neural excitation, has been studied. This was accomplished by recording the average firing rate of single units in the rat cochlear nucleus in response to paired clicks in which the interval between clicks was varied over a large range. The results show that the system impulse response of all units studied was a damped oscillation. The frequency of the oscillation was equal to the characteristic frequency of the unit. On basis of these recorded responses the auto‐correlation of the system impulse response was computed. It was furthermore found that bandwidth values determined on the basis of the derived autocorrelation functions were smaller than those estimated from tuning curves and isorate curves. It is concluded that the auditory system of the rat has a higher spectral resolution in regards to double click stimulation than it has for stimulation with single pure tones. The study furthermore indicates that the sharpening of the spectral resolution of ‘the auditory system represented by unit responses in the rat cochlear nucleus is not accomplished by interactions between the time integrated output from a number of hair cells.
Dopamine‐Containing Cells in Sympathetic Ganglia
Authors: Björklund A. , Cegrell L. , Falck B. , Ritzén M. , Rosengren E. 
Published: December 2008

AbstractIn addition to noradrenaline (about 1.3–1.5 μg/g) dopamine (about 0.2 μ/g) is present in the sympathetic chains of the cat and pig. By means of a recently developed microspectro‐fluorimetric method, the cellular localization of these two catecholamines has been studied. Dopamine was found in a special type of small, intensely fluorescent cells (“SIF‐cells”) located among the adrenergic ganglion cell bodies. Most of the dopamine present in the sympathetic ganglia is probably stored in these cells.
The Transport of Halide Ions across the Membrane of Distal Rat Tubules
Authors: Danielson B. G. , Persson E. , Ulfendahl H. R. 
Published: December 2008

AbstractThe transport mechanism for chloride was studied in rat distal tubules with a free‐flow micro‐puncture technique. The tubular fluid to plasma concentration ratio (TF/P) was determined simultaneously for sodium, potassium, chloride and iodide. The experiments were designed to determine whether there is a common active carrier mechanism for halide transport out of the distal tubules with a higher affinity for iodide than for chloride. If such a transport system exists it should give rise to a lower TF/P value for iodide than for chloride. However, the TF/P value for iodide was 0.78 and was significantly higher than for chloride (0.39), a result which is interpreted to mean that no such active carrier transport mechanism for halides exists in the distal tubules. In our opinion the differences in TF/P values depended on a lower passive permeability for iodide than for chloride.
Water Permeability in Rat Proximal Tubules
Authors: Person E. , Ulfendahl H. R. 
Published: December 2008

AbstractThe diffusional water permeability in rat proximal tubules was studied in microperfusion experiments with triturated water. The perfusion solutions were chosen either to give no net flux or a net water flux in either direction. The diffusional water permeability at zero net water flux was 564. 10‐‐5 cm/sec. The significance of the permeability measurements made during a net flux is discussed. The osmotic water permeability was 15. 10‐‐8 cm3 cm‐2 sec‐1. (cm H2O)‐l The large differences between osmotic water permeability and diffusional water permeability in zero net flux conditions cannot be accounted for entirely by an unstirred layer effect and are interpreted to mean that water transport along osmotic gradients is mainly a bulk flow through aqueous pores and not a diffusional flow and that the proximal tubular wall is a highly porous membrane.
Differentiated Interaction between the Hypothalamic Defence Reaction and Baroreceptor Reflexes
Authors: Djojosugito A. M. , Folkow B. , Kylstra P. H. , Lisander B. , Tuttle R. S. 
Published: December 2008

AbstractAs the interrelationship of autonomic patterns involving cortico‐hypothalamic and bulbar levels is of general interest, the interaction between the hypothalamic defence reaction and the homeostatic baroreceptor reflexes was explored in cats with respect to cardiac as well as vascular effects. The results suggest, in conformity with Hilton's observations (1963), that defence area stimulation suppresses the baroreceptor reflex inhibition of the heart. On the other hand, the baroreceptor influence on vasoconstrictor fibre discharge was largely the same, whether defence area stimulations were performed or not. This had important haemodynamic consequences, especially for muscle blood flow, since the reflex inhibition of regional constrictor fibre tone could greatly enhance the cholinergic vasodilatation. Therefore such a differentiated interaction between oppositely directed central and reflex autonomic mechanisms has the consequence that the baroreceptor reflexes, rather than damping the defence reaction, act in synergism with it with respect to net haemodynamic effects; some further implications of this are dealt with in the subsequent paper (Kylstra and Lisander 1969).
Differentiated Interaction between the Hypothalamic Defence Area and Baroreceptor Reflexes
Authors: Kylstra P. H. , Lisander B. 
Published: December 2008

AbstractIn experiments on cats, the interaction between the oppositely directed hypothalamic defence reaction and the baroreceptor reflexes was analysed with particular regard to the effects on aortic blood flow, left ventricular work load and muscle blood flow. Because of their differentiated interaction — suppression of the baroreceptor reflex effect on the heart with preservation of the reflex modulation of the vascular bed (Djojosugito et al. 1969) — the baroreceptor reflex so modifies the primary defence reaction, with its intense neurogenic drive on the heart, that a greater cardiac output is gained for a given left ventricular work load. This particularly favours muscle blood supply. It follows that such a differentiated interaction between two basically opposite autonomic patterns causes them to act in synergism with respect to efficient cardiovascular performance in states of emergency.
Effect of Chlorpromazine, Mepyramine, Prenylamine and Reserpine on 5‐Hydroxytryptamine Content and Fine Structure of Rat Peritoneal Mast Cells Incubated in Vitro
Authors: Jansson Sten‐Erik 
Published: December 2008

AbstractThe mechanism of action of the drugs tested in releasing 5‐hydroxytryptamine from mast cells in vitro was studied under different incubation conditions and by observing the morphological changes associated with the amine release. It was proposed that chlorpromazine, mepyramine and prenylamine release 5‐hydroxytryptamine by a mechanism of action not requiring energy because neither did the drugs exert their maximal effect at physiological pH values nor was the release blocked by pre‐incubation with sodium cyanide. The suggestion is supported by the morphological observations revealing destructive changes of the mast cells. The reserpine induced release of 5‐hydroxytryptamine from mast cells was small upon incubation in a phosphate buffer and was completely inhibited upon incubation in a physiological medium containing divalent cations sand glucose. The release was not decreased by lowering the temperature of the incubation medium from 37°C to 23°C which indicate a mechanism of action not requiring energy. On the other hand, reserpine had a maximal releasing effect around neutral pH values and the release was totally blocked by pre‐incubation with sodium cyanide suggesting a necessity for metabolically active cells. An energy requiring mechanism of action of reserpine was further supported by the observed morphological alterations which were much of the same nature as those induced by compound 48/80.
Temperature Regulation during Continuous and Intermittent Exercise in Man
Authors: Ekblom Björn , Greenleaf Carol J. , Greenleaf John E. , Hermansen Lars 
Published: December 2008

AbstractEkblom, B. C. J. Greenleaf, J. E. Greenleaf and L. Hermansen, Temperature regulation during continuous and intermittent exercise in man. Acta physiol. scand. 1971. 81. 1–10.Body temperature changes and heat dissipation responses were studied in three well‐trained men during moderately heavy (60 % of maximal aerobic power) continuous and intermittent exercise at the same average metabolic rate and heat production. The purpose was to determine if hypothetical “work factors” induced specifically by muscular activity influenced body temperature regulation. Compared with continuous work; a) the equilibrium level of rectal temperature (Tre) during intermittent work was elevated 0.35° C which accounted for 21 % of the total Tre increase from resting, and b) the decreased sweating of 32 g/(m2. hr) during intermittent work resulted in a decreased evaporative heat loss of 18.6 kcal/(m2. hr) that could account for the increased intermittent work Tre. These responses appear to be manifestations of reduced thermoregulatory efficiency due, perhaps, to non‐linearity in the relationship of body temperature to total work rate or to non‐linearity in the contribution of non‐thermal inputs at work rates above 100 % of max. V̇O2. It is also possible that other factors play a part, such as the frequency and duration of the work and rest cycles, rate of limb movement, or circulatory factors related to postural changes.
Uptake of Serotonin in Blood Platelets in vitro. I: The Effects of Chloride
Authors: Lingjærde O. 
Published: December 2008

AbstractLingjærde, O. Jr.Uptake of serotonin in blood platelets in vitro. I: The effects of chloride. Acta physiol. scand. 1971.81. 75–83.The effects of chloride on the “active” uptake of14C‐serotonin in human blood platelets in vitro have been studied, using a phosphate buffered artificial medium. The uptake of serotonin requires the presence of chloride in the medium. The effect of chloride concentration on the rate of serotonin uptake is in agreement with Michaelis‐Menten type kinetics. The apparent Michaelis constant for chloride is about 35 mM at pH 7.2, and it is independent of the concentration of serotonin. Moreover, the apparent Michaelis constant for serotonin is independent of the concentration of chloride. Preincubation with low concentrations of chloride is accompanied by a decrease in the rate of uptake, whereas the converse is true when high concentrations of chloride are used. It is suggested that inward transport of serotonin is dependent on chloride in such a way that serotonin and chloride have to be attached to the same carrier. It is also suggested that the intracellular concentration of chloride is of importance for the rate of re‐trans‐location of the carrier from the inner to the outer surface of the membrane.
The Effect of Lactate in Canine Subcutaneous Adipose Tissue in Situ1
Authors: Fredholm Bertil B. 
Published: December 2008

AbstractFredholm, B. B.The effect of lactate in canine subcutaneous adipose tissue in situ. Acta physiol. scand. 1971.81. 110–123.Na‐L(+)‐lactate and Na‐pyruvate were administered by intraarterial infusion in canine subcutaneous adipose tissue, perfused with the dogs own blood either at a constant rate from a reservoir or by autoperfusion. The glucose uptake was found to be dependent upon the arterial glucose concentration. Similarly the uptake of lactate and pyruvate increased with increasing arterial concentrations, the latter more rapidly than the former. Infusion of Na‐L(+)‐lactate below 5 mM and Na‐D(—)‐lactate (10–11 mM) had no effect on the release of FFA and glycerol upon nerve stimulation (4 cps for 5 to 10 min). On the other hand Na‐L(+)‐lactate above 10 mM caused a 70 per cent inhibition of the release of FFA without significantly affecting the glycerol release. Na‐pyruvate (5 mM) decreased the glycerol output significantly, but increased the FFA release. Neither of the anions had any significant effect on the glucose uptake. Na‐lactate was not vasoactive, whereas Na‐pyruvate was slightly vasodilator.It is concluded that lactate in concentrations occurringa.g. during muscular exercise and shock is capable of significantly depressing the rate of FFA release upon nerve stimulation by increasing the rate of re‐esterification. The finding that lactate and pyruvate had opposite effects on esterification indicates a role of the cytoplasmatic NADH/NAD ratio in determining the rate of esterification.