摘要:

AbstractEkblom, B. C. J. Greenleaf, J. E. Greenleafand 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 Treincrease 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 p

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb04871.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractAndersson, R., E. Mohme‐Lundholm, N. Svedmyrand N. Vamos,Relaxing and metabolic actions of ACTH in rabbit colon. Acta physiol. scand. 1971.81. 11–17.ACTH in the dose range of 0.15–4.60 IU/ml relaxed the circular muscular layer of rabbit colon contracted by carbacholine. The content of cyclic AMP was doubled. There was an activation of phosphorylaseawhich gave the same dose‐effect and time‐effect curves as thc relaxing action. The hexose phosphate and creatine phosphate contents of the muscle also increased. The relaxing and metabolic actions of ACTH were completely blocked by an adrenergic β‐receptor blocking agent (sotalol). The type of inhibition was competive. The relaxing action of ACTH was potentiated by theophylline and puromycin, agents which inhibit the enzymatic hydrolysis of cyclic AMP. The relaxing and metabolic actions of ACTH were similar to those of isoprenaline. They could be reproduced by cyclic AMP. In contrast to cyclic AMP and isoprenaline, ACTH did not decrease the adenosine triphosphate contcnt of thc muscle. It is suggested that the relaxing action of ACTH is mediated by thc adcnyl cyclase‐cyc

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb04872.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractAndersson, B. and L. Eriksson,Conjoint action of sodium and angiotensin on brain mechanisms controlling water and salt balances. Acta physiol. scand. 1971.81. 18–29.The effects on water and salt balances of a simultaneous infusion of angiotensin and hypertonic NaCl into the 3rd brain ventricle were studied in goats in normal water balance and in hydrated animals. For comparison similar infusions of angiotensin alone (solved in slightly hypotonic saline) and of hypertonic NaCl were made. Like the hypertonic NaCl, 30 min infusions of angiotensin alone induced drinking in animals in normal water balance, and an inhibition of the water diuresis in the hydrated goat. The simultaneous infusion of both substances resulted in a marked potentiation of the dipsogenic and the antidiuretic effects. A possible explanation may be that angiotensin facilitates the transport of Na+into brain cells regulating thirst and ADH release, and that the intracellular Na+concentration rather than strictly osmotic factors determines the activity of these cells. In the hydrated goat a central effect of angiotensin strongly enhanced the natriuretic response to intraventricular infusions of hypertonic NaCl, and extreme natriuresis developed as result of the combined infusions in hydrated, salt‐supplemented animals. During normal water balance this sodium‐angiotensin synergism was less obvious, which suggests that both an expanded fluid volume and an elevated intracellular Na+concentration are needed for optimal activation of a brain mechanism which stimulates renal Na' excretion, The time course of the centrally induced natriuresis indicates that the effect on the kidney may be mediated by a humoral

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb04873.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractPátkai, P.The diurnal rhythm of adrenaline secretion in subjects with different working habits. Acta physiol. scand. 1971.81. 30–34.Subjects classified as habitual morningvs. evening workers on the basis of their answers to a questionnaire, were compared with regard to catecholamine excretion under conditions of relaxation in the morning and in the evening. It was shown that individuals who preferred to work in the evening, excreted more adrenaline in the evening than in the morning, while individuals characterized by morning alertness excreted more adrenaline in the morning than in the evening, also when relaxing. With regard to noradrenaline excretion there was no marked difference between the grou

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb04874.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractPátkai, P.Interindividual differences in diurnal variations in alertness, performance, and adrenaline excretion. Acta physiol. scand. 1971.81. 35–46.Subjects classified as habitual morning vs. evening workers on the basis of their answers to a questionnaire, were compared with regard to day‐time variations in catecholamine excretion and performance. Adrenaline excretion in morning workers was highest in the morning and decreased gradually during the day, while evening workers showed nearly constant excretion values. The performance of morning workers did not vary during the day, while evening workers showed a steady improvement, performing best in the evening. In addition, a significant difference between the two groups was found in the personality dimension of extraversion‐introversion, showing that evening workers were more extravert and morning workers more introvert. The constancy of individual diurnal rhythms and their relations to personality traits, are dis

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb04875.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractArfors, K.‐E., G. Artursonand P. Malmberg,Effect of prolonged chloralose anesthesia on acid‐base balance and cardiovascular functions in dogs. Acta physiol. scand. 1971.81. 47–53.Dogs under light even α‐chloralose anesthesia of 6 hrs duration showed no time dependent effect of anesthesia on mean arterial pressure, cardiac index and oxygen consumption. The Pacon remained stable as did respiratory rate, but base excess decreased moderately and heart rate increased. Compared with a group of conscious dogs Paco2and mean arterial pressure were slightly i

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb04876.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractBroman, Svetlanaand O. Wigertz,Transient dynamics of ventilation and heart rate with step changes in work load from different load levels. Acta physiol. scand. 1971.81. 54–74.Transient dynamics of ventilation (V̇) and heart rate (HR) in response to 650 kpm/min step changes in work load were analyzed in six male athletes performing submaximal cycling exercise in the supine position, with the steps initiated at different levels of stable‐state exercise, including “loadless” pedaling (0 kpm/min). By applying mathematical parameter identification, the responses of V̇ to both positive and negative step changes in work load could be accurately described by first‐order exponential models. With the positive steps initiated at 0, 300, and 650 kpm/min, the means of the time constant estimates for V̇ ranged from 67 to 101 sec, and seemed to be independent of the initial work level. Shifting from rest to pedaling at zero load and back to rest caused abrupt changes in V̇, whereas this was rarely the case after step changes from one work load to another with the subjects already pedaling. The responses of HR required second‐order models, with the two time constants ranging from 9.0 to 11.7 sec and from 1.8 to 3.7 min, and with the share of the slower component increasing with the initial work level. Pure time delays were negligible, indicating that the early readjustments in both V and HR are under neurogenic influence. The results support the notion that in exercise the respiratory and circulatory control systems exhibit dissociated dyn

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb04877.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

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 o

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb04878.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractLisander, B. and J. Martner,Cerebellar suppression of the autonomic components of the defence reaction. Acta physiol. scand. 1971.81. 84–95.Experiments were performed on anesthetized‐curarized cats, where both the hypothalamic defence area and the cortex of the anterior cerebellar lobe could be stimulated while blood pressure, heart rate and muscle blood flow were recorded. Cerebellar stimulation which, when performed alone, had only insignificant cardiovascular effects, considerably reduced the increases in heart rate, blood pressure and muscle blood flow elicited by standardized defence area stimulations. The cerebellar suppression of the muscle vasodilatation appeared to be due to an interference with the cholinergic vasodilator fibre activation as elicited from the defence area. Thus, after complete pharmacological blockade of all adrenergic effects on the cardiovascular system, defence area stimulation still caused a marked, atropine‐sensitive muscle vasodilatation but this dilatation could be reduced by comcomitant cerebellar stimulation. In contrast, even strong activations of the baroreceptors did not interfere with the vasodilator fibre discharge as elicited from the defence area.Therefore, while the inhibitory baroreceptor reflex and the defence reaction because of their differentiated interaction act in synergism from the hemodynamic point of view (see Kylstra and Lisander 1970) the cortex of the anterior cerebellar lobe tends to suppress the defence reaction by exerting an inhibitory influence on essentially all the autonomic components of this response pa

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb04879.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY

摘要:

AbstractÖberg, P. Å. and U. Sjöstrand,Studies of blood‐pressure regulation. III. Dynamics of arterial blood pressure on carotid‐sinus nerve stimulation. Acta physiol. scand. 1971.81. 96–109.An analysis of the properties of the blood pressure regulatory system has been made by means of carotid‐sinus nerve stimulation. The method used involves analog simulation of the nonlinear properties of this reflex. The analysis gives the gain‐frequency and the gain‐phase shift curves characterizing the system under study. A resonance frequency for the system is mostly found in the frequency range 0.03–0.06 Hz. Modulation of the control signal decreases the systemic bandwidth. Non‐linear simulation indicates that the mammalian blood pressure regulating system has some of the characteristics of a sampled regulatory system. The afferent information in the carotid‐sinus baroreceptor reflex stabilizes the systemic blood pressure by means of its pulsating nature. Transfer functions characterizing the system under study are given. The data presented are relevant to the functional characteristics

ISSN:0001-6772    

DOI:10.1111/j.1748-1716.1971.tb04880.x

出版商:Blackwell Publishing Ltd    

年代:1971

数据来源: WILEY