Ovulation delay induced by blockade of the cholinergic system on dioestrus-1, is related to changes in dopaminergic activity of the preoptic anterior-hypothalamic area of the rat.
One hour after the injection of 100 mg/kg of atropine-sulphate at 1300 h of dioestrus-1, there was an abrupt increase of 17beta-oestradiol plasma level and a significant increase in dopaminergic neural activity in preoptic anterior-hypothalamic area, without changes in luteinizing hormone serum level, in comparison with the saline injected group. Animals injected with atropine-sulphate showed a second increase in dopaminergic neural activity in the preoptic anterior-hypothalamic at 1100 of dioestrus-2 (atropine-sulphate 0.471 +/- 0.7 vs. saline 0.241 +/- 0.03, p < 0.01). In this group of animals, the preovulatory surges of 17beta-oestradiol and luteinizing hormone occurred simultaneously at 1700 h of the expected day of oestrus; spontaneous ovulation was delayed until the expected day of dioestrus-1. Present results suggest that during dioestrus-1 there is a functional relationship between the cholinergic and dopaminergic systems in preoptic anterior-hypothalamic area, regulating the release of luteinizing hormone resulting in ovulation.
Cruz
M E
ME
Laboratorio de Neuroendocrinología, Unidad de Investigación en Biología de la Reproducción, Facultad de Estudios Superiores Zaragoza, Universidad Nacional Autónoma de México, México City, Mexico. timov@servidor.unam.mx
Villegas
G
G
Domínguez-González
A
A
Chavira
R
R
Domínguez
R
R
D015102:3,4-Dihydroxyphenylacetic Acid / Q000378:metabolism; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D004031:Diestrus / Q000187:drug effects* / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D004958:Estradiol / Q000097:blood*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000187:drug effects / Q000378:metabolism; D007986:Luteinizing Hormone / Q000097:blood* / Q000187:drug effects; D018727:Muscarinic Antagonists / Q000494:pharmacology; D010060:Ovulation / Q000187:drug effects* / Q000378:metabolism; D011301:Preoptic Area / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D011976:Receptors, Muscarinic / Q000187:drug effects / Q000378:metabolism
D018727:Muscarinic Antagonists; D011976:Receptors, Muscarinic; D015102:3,4-Dihydroxyphenylacetic Acid; D007987:Gonadotropin-Releasing Hormone; D004958:Estradiol; D001285:Atropine; D007986:Luteinizing Hormone; D004298:Dopamine