Histamine-induced prolactin release and activity of tuberoinfundibular dopaminergic neurons in male rats.
The role of tuberoinfundibular dopamine (DA) in the histamine-induced rise of plasma prolactin was studied in male rats. Right lateral ventricle (icv) histamine injection (30 micrograms/rat) caused a significant rise of plasma prolactin at 15 and 30 min; at 60 min values returned to basal levels. Histamine does not modified steady-state DA concentrations. For turnover evaluation, histamine was icv injected immediately or 30 min after the tyrosine hydroxylase inhibitor alpha-methyltyrosine (250 mg/kg i.p.) and DA concentration in the median eminence was measured at 0, 1 and 2 hours after the inhibitor injection. Rate constants of DA decline and DA synthesis rates were found similar in both controls (cerebrospinal fluid) and histamine-injected rats. These results indicate that the stimulatory action of histamine on prolactin release might not be associated to DA. It would be due mainly to its action on prolactin-releasing factors and to a minor extent, to changes in the dopaminergic system.
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Seltzer
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Donoso
D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D006632:Histamine / Q000494:pharmacology*; D008297:Male; D008473:Median Eminence / Q000187:drug effects / Q000502:physiology*; D008781:Methyltyrosines / Q000494:pharmacology; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D011388:Prolactin / Q000378:metabolism*; D051381:Rats
D008781:Methyltyrosines; C022260:alpha-methyltyrosine methyl ester; D006632:Histamine; D011388:Prolactin; D004298:Dopamine