Changes in blood pressure and dipsogenic responsiveness to angiotensin II during chronic exposure of rats to cold
- Univ. of Florida, Gainesville (United States)
To assess the role of the renin-angiotensin (RA) system in the development of cold-induced hypertension in rats, systolic blood pressure (SBP), plasma renin activity (PRA), and the dipsogenic responsiveness to s.c. administration of angiotensin II (AII) were measured weekly for 4 weeks. SBP increased significantly during the third week of exposure to cold (5C), compared to warm-adapted controls. A significant increase in SBP occurred during the third week of cold. In contrast, (PRA) increased within the first week of cold, and declined thereafter to reach the level of the control by the third week. By the fourth week, PRA decreased to a level significantly below that of control. The dipsogenic responsiveness to acute administration of AII increased significantly by the third week of cold and remained significantly elevated during the fourth week. There was a significant direct relationship between dipsogenic responsiveness to AII and SBP in the cold-treated but not the control group. There was also a significant indirect linear relationship between PRA and dipsogenic responsiveness to AII. Cold-treated rats had significant increases in urinary norepinephrine output and weights of heart, kidneys, adrenals, and brown adipose tissue. Thus, the results suggest, but do not prove, either that the elevation of blood pressure under these conditions may be induced by changes in the RA system. The results suggest further that the reduction in the drinking response to AII accompanying increases in PRA may be related to changes in the regulation of central receptors for AII.
- OSTI ID:
- 5376017
- Report Number(s):
- CONF-9104107--
- Journal Information:
- FASEB Journal (Federation of American Societies for Experimental Biology); (United States), Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States) Vol. 5:4; ISSN 0892-6638; ISSN FAJOE
- Country of Publication:
- United States
- Language:
- English
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63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADRENAL HORMONES
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOLOGICAL EFFECTS
BLOOD PRESSURE
BODY TEMPERATURE
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR DISEASES
CHRONIC EXPOSURE
DISEASES
DRUGS
ENZYME ACTIVITY
ENZYMES
HORMONES
HYDROLASES
HYPERTENSION
HYPOTHERMIA
MAMMALS
NEUROREGULATORS
NORADRENALINE
ORGANIC COMPOUNDS
PEPTIDE HYDROLASES
PROTEINS
RATS
RODENTS
SYMPATHOMIMETICS
SYMPTOMS
TEMPERATURE EFFECTS
VASCULAR DISEASES
VERTEBRATES