Evidence that histamine-stimulated prolactin secretion is not mediated by an inhibition of tuberoinfundibular dopaminergic neurons.
The effects of histamine on prolactin secretion and the activity of tuberoinfundibular dopaminergic (DA) neurons were examined in male rats. Tuberoinfundibular DA neuronal activity was estimated in situ by measuring the metabolism [concentration of 3,4-dihydroxyphenylacetic acid (DOPAC)] and synthesis [accumulation of 3,4-dihydroxyphenylalanine (DOPA) after administration of a decarboxylase inhibitor] of dopamine in the median eminence. Intracerebroventricular (icv) injection of histamine produced a dose- and time-dependent increase in plasma prolactin levels but had no effect on DOPA accumulation or DOPAC concentrations in the median eminence. These results indicate that the stimulation of prolactin secretion following icv histamine is not mediated by an inhibition of tuberoinfundibular DA neurons.
Fleckenstein
A E
AE
Department of Pharmacology and Toxicology, Michigan State University, East Lansing 48824.
Lookingland
K J
KJ
Moore
K E
KE
D015102:3,4-Dihydroxyphenylacetic Acid / Q000097:blood / Q000378:metabolism; D000818:Animals; D004295:Dihydroxyphenylalanine / Q000378:metabolism; D004298:Dopamine / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D006632:Histamine / Q000008:administration & dosage / Q000494:pharmacology*; D007276:Injections, Intraventricular; D007700:Kinetics; D008297:Male; D008473:Median Eminence / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D011388:Prolactin / Q000378:metabolism*; D051381:Rats
D015102:3,4-Dihydroxyphenylacetic Acid; D004295:Dihydroxyphenylalanine; D006632:Histamine; D011388:Prolactin; D004298:Dopamine