title: Effects of hypothalamic dopamine (DA) on salsolinol (SAL)-induced prolactin (PRL) secretion in male goats.
abstract: The aim of the present study was to clarify the effects of hypothalamic dopamine (DA) on salsolinol (SAL)-induced prolactin (PRL) release in goats. The PRL-releasing response to an intravenous (i.v.) injection of SAL was examined after treatment with augmentation of central DA using carbidopa (carbi) and L-dopa in male goats under 8-h (8 h light, 16 h dark) or 16-h (16 h light, 8 h dark) photoperiod conditions. The carbi and L-dopa treatments reduced basal PRL concentrations in the 16-h photoperiod group (P < 0.05), while a reduction was not observed in the 8-h photoperiod group. The mean basal plasma PRL concentration in the control group for the 8-h photoperiod was lower than that for the 16-h photoperiod (P < 0.05). SAL significantly stimulated the release of PRL promptly after the injection in both the 8- and 16-h photoperiod groups (P < 0.05). PRL-releasing responses for the 16-h photoperiod were greater than those for the 8-h photoperiod (P < 0.05). The carbi and L-dopa treatments blunted SAL-induced PRL release in both the 8- and 16-h photoperiods (P < 0.05). These results indicate that hypothalamic DA blunts the SAL-induced release of PRL in male goats, regardless of the photoperiod, which suggests that both SAL and DA are involved in regulating the secretion of PRL in goats.
authors: Faculty of Agriculture, Iwate University, Morioka, Japan.
authors: Jin
authors: J
authors: Jin
authors: Sayaka
authors: S
authors: Hara
authors: Ken
authors: K
authors: Sawai
authors: Ferenc
authors: F
authors: Fülöp
authors: György Miklos
authors: GM
authors: Nagy
authors: Tsutomu
authors: T
authors: Hashizume
mesh_terms: D000818:Animals; D002230:Carbidopa / Q000494:pharmacology*; D004298:Dopamine / Q000502:physiology*; D006041:Goats / Q000502:physiology*; D007031:Hypothalamus / Q000502:physiology*; D007275:Injections, Intravenous; D007546:Isoquinolines / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D007980:Levodopa / Q000494:pharmacology*; D008297:Male; D017440:Photoperiod; D011388:Prolactin / Q000378:metabolism*; D013268:Stimulation, Chemical; D013997:Time Factors
chemical_list: D007546:Isoquinolines; D007980:Levodopa; D011388:Prolactin; C036617:salsolinol; D002230:Carbidopa; D004298:Dopamine
keywords: dopamine; goats; photoperiod; prolactin; salsolinol