Dipsogenic effect of L-5-hydroxytryptophan in rats.
The precursor of serotonin, l-hydroxytryptophan (5HTP), is a potent dipsogen in the rat. Peripheral administration of increasing doses of this compound increased water intake in a dose-dependent fashion. Peripheral administration of other analogs of tryptophan, including d-tryptophan, l-tryptophan and acetyltryptophan, failed to affect water intake at a dose at which 5HTP induced maximal drinking (25 mg/kg, SC). The dipsogenic effect of melatonin, one of the metabolites of serotonin, was also tested. At any of 6 different doses (0.5 to 50 mg/kg, SC), melatonin failed to affect water intake in the rat. The mechanism by which 5HTP induces drinking is not known with certainty but could involve its conversion to serotonin, a known dipsogenic agent.
D006916:5-Hydroxytryptophan / Q000494:pharmacology*; D000818:Animals; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004326:Drinking / Q000187:drug effects*; D005260:Female; D051381:Rats; D013237:Stereoisomerism; D014364:Tryptophan / Q000031:analogs & derivatives / Q000494:pharmacology; D014882:Water-Electrolyte Balance / Q000187:drug effects
C006392:N-acetyltryptophan; D014364:Tryptophan; D006916:5-Hydroxytryptophan; D004121:Dimethyl Sulfoxide