Involvement of angiotensin in water intake induced by peripheral administration of a serotonin agonist, 5-carboxyamidotryptamine.
Rats were given peripheral injections of a 5HT1 agonist, 5-carboxy-amidotryptamine (5-CT), and various behavioral, physiological, and neuronal outcomes were documented. 5-CT caused short latency water intake. In rats with a choice between water and hypertonic NaCl, about half of the rats drank only water while the other half showed an initial robust intake of NaCl. Blood pressure was reduced and plasma renin activity increased following 5-CT. The effective half life was 1-3 h, with water intake inhibiting further consumption. Fos-like immunoreactivity (FLI) was induced by 5-CT in regions of the brain identical to those previously shown to be activated by peripheral administration of angiotensin (Ang) II. The role of endogenously-generated Ang II in the dipsogenic action of 5-CT was suggested because captopril inhibited the water intake. Possible mechanisms of 5-CT and Ang II-induced thirst are reviewed, including roles of hypotension and the vagus nerve.
Rowland
N E
NE
Department of Psychology, University of Florida, Gainesville 32611-2250.
Li
B H
BH
Fregly
M J
MJ
Smith
G C
GC
D000704:Analysis of Variance; D000804:Angiotensin II / Q000502:physiology*; D000818:Animals; D001066:Appetite / Q000187:drug effects*; D001794:Blood Pressure / Q000187:drug effects; D004326:Drinking / Q000187:drug effects* / Q000502:physiology; D007124:Immunoenzyme Techniques; D008297:Male; D009419:Nerve Tissue Proteins / Q000032:analysis; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012083:Renin / Q000097:blood; D012701:Serotonin / Q000031:analogs & derivatives* / Q000494:pharmacology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*; D012982:Sodium, Dietary / Q000008:administration & dosage; D013997:Time Factors
D009419:Nerve Tissue Proteins; D016760:Proto-Oncogene Proteins c-fos; D017366:Serotonin Receptor Agonists; D012982:Sodium, Dietary; D000804:Angiotensin II; D012701:Serotonin; C047087:5-carboxamidotryptamine; D012083:Renin