Glucocorticoids potentiate the dipsogenic action of angiotensin II

R Ganesan, C Sumners - Brain research, 1989 - Elsevier
R Ganesan, C Sumners
Brain research, 1989Elsevier
The effect of a short-term, acute treatment with a glucocorticoid, dexamethasone sodium
phosphate, on the drinking induced by angiotensin II (AII) was investigated in a series of
experiments. Initial studies indicated that a single injection of dexamethasone (700–750
μg/kg, ip) reduced food intake, body weight and water intake for up to 48 h, but had little
effect on blood pressure when it was measured 6 h subsequent to the injection. The drinking
elicited by peripherally administered AII (200 μg/kg, sc) was enhanced if the glucocorticoid …
Abstract
The effect of a short-term, acute treatment with a glucocorticoid, dexamethasone sodium phosphate, on the drinking induced by angiotensin II (AII) was investigated in a series of experiments. Initial studies indicated that a single injection of dexamethasone (700–750 μg/kg, i.p.) reduced food intake, body weight and water intake for up to 48 h, but had little effect on blood pressure when it was measured 6 h subsequent to the injection. The drinking elicited by peripherally administered AII (200 μg/kg, s.c.) was enhanced if the glucocorticoid (700 μg/kg, i.p.) was given 3 h or 6 h prior to the dipsogen. There was no effect of pretreatment with the steroid if the drinking test was delayed by 24 h. The subsequent experiment showed that the glucocorticoid effect on AII-stimulated drinking was dose dependent (100 μg–1600 μg/kg). The drinking stimulated by intracerebroventricular (i.c.v.) AII (2.5 ng) was enhanced in terms of volume and total duration by prior treatment with dexamethasone, but i.c.v. carbachol (200 ng)-induced drinking remained unaffected. The final study showed that binding of AII to its receptors in five different areas of the rat brain was not affected by prior treatment with dexamethasone.
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