Effects of serotonin, GABA and neuropeptide Y on seabream gonadotropin releasing hormone release in vitro from preoptic-anterior hypothalamus and pituitary of red seabream, Pagrus major.
The effects of serotonin (5-HT), GABA and neuropeptide Y (NPY) on in vitro release of seabream (sb) gonadotropin releasing hormone (GnRH) from slices of the preoptic-anterior hypothalamus (P-AH) and pituitary of red seabream were studied. 5-HT, GABA and NPY all stimulated the release of sbGnRH from the P-AH but not from the pituitary of immature red seabream. They also stimulated sbGnRH release from the P-AH with a similar potency during the course of gonadal development. Specific agonists and/or antagonists of 5-HT, GABA and NPY showed that 5-HT and GABA utilize 5-HT(2) and GABAA receptor subtypes, respectively, to mediate their action, and that NPY employs at least NPY(Y1) and NPY(Y2) receptor subtypes to stimulate sbGnRH release. Combinations of different antagonists for 5-HT, GABA and noradrenaline/adrenaline did not block the stimulatory influence of NPY on release of sbGnRH, indicating that the action of NPY on the sbGnRH neuronal system is probably direct.
Senthilkumaran
B
B
Inland Station of National Research Institute of Aquaculture, Tamaki, Mie, Japan.
Okuzawa
K
K
Gen
K
K
Kagawa
H
H
D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D004837:Epinephrine / Q000037:antagonists & inhibitors; D005260:Female; D018756:GABA Antagonists / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007650:Ketanserin / Q000494:pharmacology; D008297:Male; D009478:Neuropeptide Y / Q000819:agonists / Q000494:pharmacology; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D009638:Norepinephrine / Q000037:antagonists & inhibitors; D009924:Organ Culture Techniques; D010902:Pituitary Gland / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D011301:Preoptic Area / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D012098:Reproduction; D021541:Sea Bream / Q000378:metabolism*; D012701:Serotonin / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology
D018756:GABA Antagonists; D009478:Neuropeptide Y; D018377:Neurotransmitter Agents; D012702:Serotonin Antagonists; D012701:Serotonin; D007987:Gonadotropin-Releasing Hormone; D005680:gamma-Aminobutyric Acid; D007650:Ketanserin; D009638:Norepinephrine; D001640:Bicuculline; D004837:Epinephrine