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Title: Hypertension during chronic exposure to cold: Comparison between Sprague Dawley (SD) and Long Evans (LE) strains

Hypertension accompanies chronic exposure of SD rats to cold (5-6C), including elevation of systolic, diastolic, and mean blood pressures and cardiac hypertrophy. The renin-angiotensin system may play an important role. Earlier studies suggested that the LE strain may have a decrease in angiotensin I converting enzyme (ACE) activity. Measurement of ACE activity in plasmas of SE and LE strains revealed that basal activity of ACE in the plasma of the LE strain was significantly less than that of the SD strain. A second study was carried out in which both strains were exposed to cold for 7 weeks. There were clear differences between strains. Rats of the SD strain had a significant elevation in their blood pressure; a significantly increased urinary output of norepinephrine (NE) and epinephrine (E); and significant increases in weights of heart, kidneys, adrenals, and brown adipose tissue (IBAT) compared to their controls maintained at 26C. In contrast, rats of the LE strain were less responsive to cold in that blood pressure failed to rise as sharply and to attain as high a level; NE and E outputs, as well as weights of heart and IBAT were significantly less than those of rats of the cold-treated SDmore » strain. Thus, the lower ACE activity in plasma of LE strain, as well as a reduced secretion of catecholamines, may protect these rats against the rise of blood pressure characteristically observed when rats of the SD strain are exposed to cold.« less
Authors:
; ;  [1]
  1. (Univ. of Florida, Gainesville (United States))
Publication Date:
OSTI Identifier:
5374753
Report Number(s):
CONF-9104107--
Journal ID: ISSN 0892-6638; CODEN: FAJOE
Resource Type:
Conference
Resource Relation:
Journal Name: FASEB Journal (Federation of American Societies for Experimental Biology); (United States); Journal Volume: 5:4; Conference: 75. annual meeting of the Federation of American Societies for Experimental Biology (FASEB), Atlanta, GA (United States), 21-25 Apr 1991
Country of Publication:
United States
Language:
English
Subject:
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.; HYPERTENSION; PATHOGENESIS; HYPOTHERMIA; BIOLOGICAL EFFECTS; PEPTIDE HYDROLASES; ENZYME ACTIVITY; RATS; BLOOD PRESSURE; ADRENALINE; CATECHOLAMINES; CHRONIC EXPOSURE; GENETIC VARIABILITY; NORADRENALINE; RENIN; TEMPERATURE EFFECTS; ADRENAL HORMONES; AMINES; ANIMALS; AROMATICS; AUTONOMIC NERVOUS SYSTEM AGENTS; BIOLOGICAL VARIABILITY; BODY TEMPERATURE; CARDIOTONICS; CARDIOVASCULAR AGENTS; CARDIOVASCULAR DISEASES; DISEASES; DRUGS; ENZYMES; HORMONES; HYDROLASES; HYDROXY COMPOUNDS; MAMMALS; NEUROREGULATORS; NONSPECIFIC PEPTIDASES; ORGANIC COMPOUNDS; PHENOLS; POLYPHENOLS; PROTEINS; RODENTS; SYMPATHOMIMETICS; SYMPTOMS; VASCULAR DISEASES; VERTEBRATES 560200* -- Thermal Effects