ISSN:1018-1172    

DOI:10.1159/000157995

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Intracranial vessels are well innervated by both adrenergic and cholinergic nerves. They possess adrenergic and cholinergic receptors. A contractile response can be provoked by various amines, and noradrenaline can be released from the axons in the perivascular nerve plexus in amounts sufficient to induce strong vasoconstriction. The close relationship between adjacent perivascular cholinergic and adrenergic nerve terminals, also in the neuroeffector area, suggests axonal interaction. It is proposed that the autonomic innervation of brain vessels participates in the control not only of the cerebral circulation but also of associated intracranial pressure phenomena.

ISSN:1018-1172    

DOI:10.1159/000157996

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Dog gracilis muscles were removed, enclosed in a plethysmograph and perfused at an inflow pressure of 110 mm Hg. Venous outflow pressure was 3 mm Hg. Circulating blood volumes were measured by the constant infusion technique using RBC-51Cr (9 muscles) or albumin-131I (11 muscles). Volumes were calculated from the infusion and from the washout of the indicator. Skeletal muscle contraction was produced by stimulation of the gracilis nerve stump with supramaximal stimuli at 2-15 Hz for 15-60 sec. Volume changes during and following the stimulations were measured by plethysmography and by changes in total muscle radioactivity. Inflow and outflow were also measured. Changes in interstitial fluid volume were calculated as the difference between total tissue and vascular volume changes. Blood volume increased at all contraction rates. Total tissue volume initially decreased during the contraction period and then returned to control. Extravascular volume decreased markedly during the initial period of contraction and then increased above control, returning to the control level following the end of the stimulation. The tissue pressure markedly increased during the contractions causing fluid movement into the vascular system. Minimal loss of labeled albumin during the period of contraction indicated capillary permeability was not altered.

ISSN:1018-1172    

DOI:10.1159/000157997

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

The present investigation was undertaken to study the inactivation of endogenous noradrenaline (NA) released by electrical stimulation of the dog saphenous vein strips. Electrical stimulation of this preparation caused contractile responses which were due to release of NA. Relaxation curves were determined after oil immersion. Cocaine (10–5 m) blocked the greatest part of the inactivation capacity showing that most of the released NA that acts on the α-adrenergic receptors is taken up by sympathetic nerves. Neither monoamine oxidase (MAO) nor catechol-O-methyl transferase (COMT) nor uptake2 seem to play important roles in the inactivation of endogenous NA. After blockade of neuronal uptake by cocaine, both cortexone (6 × 10–5 m), an inhibitor of uptake2, and U-0521 (10–4 m) (3,4-dihydroxy-2-methyl propiophenone), an inhibitor of COMT, blocked a significant part of the remaining inactivation capacity showing that uptake2 and COMT metabolism can represent an alternative to neuronal uptake. After cocaine, iproniazid (7 × 10–4 m) was ineffective. The relative roles of the different mechanisms of inactivation of endogenous NA are different from those for exogenous NA in the dog saphenous v

ISSN:1018-1172    

DOI:10.1159/000157998

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Cell Na in the rat tail artery was measured by replacing all extracellular Na with Li at 2°C. Water was partitioned with 14C-sorbitol as the marker. The binding capacity of the cytoplasm was estimated by ion-exchange after the destruction of cell membranes by alternate freezing and thawing. Cell Na is of the order of 20–25 mEq/kg dry weight and about 2/3 of this may be in free solution with [Na]i in the range of 15 mEq/liter. Cell K is about 220 mEq/kg dry weight and, of this, 30 mEq or more is bound so that [K]i is not greater than 190 mEq/liter. These estimates allow only for the low figure of 30 mEq as the sum of site-bound cell monovalent cations. It is shown, however, that as much as 50-60 mEq may be site-bound or otherwise restricted within the cell. A similar amount, mostly Na+, is site-bound within the paracellular matr

ISSN:1018-1172    

DOI:10.1159/000157999

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

The electrical activity of longitudinal muscle of anterior mesenteric artery from domestic fowl was investigated with microelectrodes and in the sucrose-gap apparatus. Action potentials were recorded by both techniques. In the sucrose-gap each action potential preceded a phasic contraction and similar contractions were recorded in vivo suggesting that during life, action potentials are normally associated with the generation of tension. Measured with microelectrodes in hypertonic solution at 41 °C, the time constant of the muscle was 257 msec and the space constant 2.8 mm. The latter was unchanged when reducing the tem perature to 31 °C but the former was increase

ISSN:1018-1172    

DOI:10.1159/000158000

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Vascular catecholamine fluorescence was studied in human gingival tissue obtained from subjects of different ages. An inverse relationship between fluorescence brightness and age was demonstrated. This finding was considered as possible evidence for a decline in direct sympathetic vascular control in older subjects, and its significance is discussed in the context of other age-related hanges in the sympathetic nervous system.

ISSN:1018-1172    

DOI:10.1159/000158001

出版商:S. Karger AG    

年代:1974

数据来源: Karger

摘要:

Prostaglandin A (PGA) compounds infused intravenously at rates of 0.125, 0.25 and 0.50 µg/kg/min decreased mean aortic pressure and renal vascular resistance, but did not increase renal blood flow in pentobarbital-anesthetized dogs. In contrast, dopamine increased renal blood flow at infusion rates of 2.5, 5.0 and 7.5 µg/kg/min and increased mean aortic pressure at infusion rates of 5.0 and 7.5 µg/kg/min. With simultaneous infusions of PGA (0.125 and 0.25 µg/kg/min) and dopamine (2.5, 5.0 and 7.5 µg/kg/min), mean aortic pressure decreased and renal blood flow increased. In open-chest dogs, cardiac contractile force was increased more by dopamine than by PGA. Neither agent alone altered heart rate, but when administered together, heart rate increased. PGA (0.01–0.02 µg/kg/min) abolished the increase in blood pressure produced by larger doses of dopamine (15–20 µg/kg/min) without reducing the increase in renal blood flow. Thus, by varying infusion rates of dopamine and PGA, renal blood flow may be increased with no change, an increase or a decrease in arteria

ISSN:1018-1172    

DOI:10.1159/000158002

出版商:S. Karger AG    

年代:1974

数据来源: Karger

ISSN:1018-1172    

DOI:10.1159/000158003

出版商:S. Karger AG    

年代:1974

数据来源: Karger