Hypertension during chronic exposure to cold: Comparison between Sprague Dawley (SD) and Long Evans (LE) strains
- Univ. of Florida, Gainesville (United States)
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 SD 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.
- OSTI ID:
- 5374753
- 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 FAJOE; ISSN 0892-6638
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ADRENAL HORMONES
ADRENALINE
AMINES
ANIMALS
AROMATICS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOLOGICAL EFFECTS
BIOLOGICAL VARIABILITY
BLOOD PRESSURE
BODY TEMPERATURE
CARDIOTONICS
CARDIOVASCULAR AGENTS
CARDIOVASCULAR DISEASES
CATECHOLAMINES
CHRONIC EXPOSURE
DISEASES
DRUGS
ENZYME ACTIVITY
ENZYMES
GENETIC VARIABILITY
HORMONES
HYDROLASES
HYDROXY COMPOUNDS
HYPERTENSION
HYPOTHERMIA
MAMMALS
NEUROREGULATORS
NONSPECIFIC PEPTIDASES
NORADRENALINE
ORGANIC COMPOUNDS
PATHOGENESIS
PEPTIDE HYDROLASES
PHENOLS
POLYPHENOLS
PROTEINS
RATS
RENIN
RODENTS
SYMPATHOMIMETICS
SYMPTOMS
TEMPERATURE EFFECTS
VASCULAR DISEASES
VERTEBRATES