Modulation of autonomic nervous system adjustments to heat stress by central ANG II receptor antagonism

Kevin C Kregel; Herald Stauss; Thomas Unger

doi:10.1152/ajpregu.1994.266.6.r1985

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Modulation of autonomic nervous system adjustments to heat stress by central ANG II receptor antagonism

Journal article

Peer reviewed

Modulation of autonomic nervous system adjustments to heat stress by central ANG II receptor antagonism

Kevin C Kregel, Herald Stauss and Thomas Unger

The American journal of physiology, Vol.266(6 Pt 2), pp.R1985-1991

06/1994

DOI: 10.1152/ajpregu.1994.266.6.r1985

PMID: 8024055

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Abstract

The purpose of this study was to determine whether central angiotensin II (ANG II) participates in mediating selected sympathetic nervous system and neuroendocrine adjustments to heat stress in conscious freely moving rats. Mean arterial pressure (MAP), heart rate (HR), splanchnic sympathetic nerve activity (SpNA), plasma arginine vasopressin (AVP) concentration, and colonic temperature were measured before and during whole body heating (42 degrees C ambient temperature). Heating was stopped when a colonic temperature of 41 degrees C was attained. On consecutive days, rats received an intracerebroventricular (icv) injection of saline (0.9%) or 25 micrograms of the ANG II AT1-selective receptor antagonist losartan 20 min before the start of heating. Neither treatment influenced control levels of any parameter. The increase above baseline for MAP at the end of heating was attenuated by > 50% in the losartan, compared with the saline trial (P < 0.05), while HR remained unchanged from control values for both trials. Pretreatment with losartan icv eliminated the increase in SpNA observed during the heating period in the saline trial. Furthermore, the magnitude of change in plasma AVP during heating was significantly elevated in rats after icv administration of saline compared with losartan. These findings indicate that central ANG II receptor antagonism significantly attenuates the heating-induced elevations in MAP, sympathetic neural activity to visceral regions, and plasma AVP and suggest that the central nervous system actions of endogenous ANG II are required for full expression of the sympathoexcitatory, pressor, and neuroendocrine responses associated with nonexertional heat stress in the conscious rat.

Angiotensin II - pharmacology

Angiotensin Receptor Antagonists

Animals

Arginine Vasopressin - blood

Autonomic Nervous System - physiopathology

Biphenyl Compounds - pharmacology

Blood Pressure - drug effects

Body Temperature

Brain - metabolism

Heart Rate - drug effects

Hot Temperature

Imidazoles - pharmacology

Injections, Intraventricular

Losartan

Male

Rats

Rats, Wistar

Stress, Physiological - physiopathology

Tetrazoles - pharmacology

Viscera - innervation

Details

Title: Subtitle: Modulation of autonomic nervous system adjustments to heat stress by central ANG II receptor antagonism
Creators: Kevin C Kregel - Department of Exercise and Sport Sciences, University of Arizona, Tucson 85721
Herald Stauss
Thomas Unger
Resource Type: Journal article
Publication Details: The American journal of physiology, Vol.266(6 Pt 2), pp.R1985-1991
DOI: 10.1152/ajpregu.1994.266.6.r1985
PMID: 8024055
ISSN: 0002-9513
eISSN: 2163-5773
Grant note: AG-12350 / NIA NIH HHS
Language: English
Date published: 06/1994
Academic Unit: Radiation Oncology; Provost Office Administration; Health and Human Physiology
Record Identifier: 9984213452902771

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