Biphasic effect of 5-methoxy-N,N-dimethyltryptamine on rat prolactin secretion.
5-Methoxy-N,N-dimethyltryptamine (5-MeODMT), a potent serotonin (5-HT) receptor agonist, exerts a biphasic effect on rat prolactin (PRL) secretion. 5-MeODMT (2.5-10 mg/kg) produces a marked, dose-related but short-lasting (less than 30 min) rise in serum PRL levels. At intervals longer than 30 min, 5-MeODMT (1-15 mg/kg) inhibits the stimulation of PRL secretion by another 5-HT agonist, 5-methoxytryptamine (5-MeOT, 10 mg/kg), by alpha-methylparatyrosine (50 mg/kg) or by haloperidol (0.15 mg/kg). 5-MeODMT did not significantly alter the PRL-releasing effect of gamma-butyrolactone (500 mg/kg) or a higher dose of haloperidol (1 mg/kg). The biphasic effect of 5-MeODMT on rat PRL secretion is shared by the centrally-acting 5-HT agonist quipazine, but not by 5-MeOT, an indole derivative excluded by the blood-brain barrier. The initial stimulation of PRL secretion by 5-MeODMT is probably due to its ability to activate postsynaptic 5-HT receptors. The subsequent inhibitory effect of 5-MeODMT appears to be due to increased functional activity of tuberoinfundibular dopamine neurons. The possible mechanisms underlying the inhibitory effect of 5-MeODMT on PRL release are discussed.
D000818:Animals; D004298:Dopamine / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D008297:Male; D008732:Methoxydimethyltryptamines / Q000494:pharmacology*; D010903:Pituitary Gland, Anterior / Q000378:metabolism; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D011985:Receptors, Serotonin / Q000187:drug effects; D012701:Serotonin / Q000031:analogs & derivatives* / Q000502:physiology*
D008732:Methoxydimethyltryptamines; D011985:Receptors, Serotonin; D012701:Serotonin; D011388:Prolactin; D004298:Dopamine