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Influence of brain angiotensin on thermoregulation and hydromineral balance during pregnancy in rats

Version 2 2024-06-13, 09:11
Version 1 2015-08-14, 12:04
journal contribution
posted on 2024-06-13, 09:11 authored by MJ Cairns, P Burns, R Di Nicolantonio, MJ McKinley, ML Mathai
During mammalian pregnancy, body temperature decreases and there are changes in fluid and electrolyte balance. Angiotensin signaling mechanisms in the brain have been shown to influence thermoregulation and body fluid balance in the nonpregnant state. We hypothesized that brain angiotensin is also implicated in adjusting these physiological systems in the pregnant rat. We compared core temperature and fluid regulation in three groups of pregnant rats: untreated rats, rats receiving continuous infusion of an AT(1) antagonist candesartan (5 microg.kg(-1).day(-1)) into a lateral cerebral ventricle to block brain AT(1) receptors, and rats receiving vehicle [artificial cerebrospinal fluid (aCSF)] vehicle. Untreated and aCSF-treated rats showed a decrease in colonic temperature (-0.5 and -0.8 degrees C respectively) by day 20 of gestation. However, rats treated with candesartan had increased colonic temperature compared with baseline (+0.9 degrees C), and their temperature was significantly higher on days 7 (P < 0.05), 17 (P < 0.05), and 20 (P < 0.001) compared with the other groups (aCSF and untreated). Daily food and water intakes and body weight were not different between the three groups. Similarly, litter sizes and pup weights were equal in all groups. Finally, the expected decreases in plasma Na(+) and osmolality during pregnancy were equivalent in all groups. This study suggests that brain angiotensin mediates the progressive decrease in body temperature that occurs during pregnancy. However, the changes in fluid balance associated with pregnancy are not dependent on brain angiotensin.

History

Journal

Journal of applied physiology

Volume

98

Pagination

1813-1819

Location

Bethesda, Md.

ISSN

8750-7587

eISSN

1522-1601

Language

eng

Publication classification

C1.1 Refereed article in a scholarly journal

Copyright notice

2005, American Physiological Society

Issue

5

Publisher

American Physiological Society