Comparative effects of 6-hydroxydopamine and alpha-adrenoceptor antagonists on intrauterine migration and spacing of blastocysts in the rat.
Sympathetic nerve terminals were destroyed by administration of 6-hydroxydopamine (2 x 50 mg/kg) at 10:00 h on Days 4 and 5 of pregnancy in the rat. In the myometrium, this treatment markedly decreased noradrenaline concentrations (by 99%, P less than 0.001), demonstrating that myometrial noradrenaline is mainly originated from sympathetic nerves; therefore after 6-hydroxydopamine, the distribution and spacing of blastocysts remain unaffected throughout the uterus. Administration of phenoxybenzamine (2 x 6 mg/kg) in the morning of Days 4 and 5, or prazosin (4 x 3 mg/kg) from 12:00 h on Day 4 until 12:00 h on Day 5 disorganized the even distribution of blastocysts from the tubal end to the cervical end of the uterine horns. These results provide evidence that a noradrenergic transmission via action on myometrial post-synaptic alpha 1-adrenoceptors is involved as a regulatory mechanism of uterine motility for distribution and spacing of blastocysts in the rat uterus.
D000818:Animals; D001755:Blastocyst; D010064:Embryo Implantation / Q000187:drug effects*; D005260:Female; D006892:Hydroxydopamines / Q000494:pharmacology*; D009215:Myometrium / Q000032:analysis / Q000187:drug effects / Q000294:innervation; D009638:Norepinephrine / Q000032:analysis; D016627:Oxidopamine; D010643:Phenoxybenzamine / Q000494:pharmacology*; D011224:Prazosin / Q000494:pharmacology*; D011247:Pregnancy; D051381:Rats; D011919:Rats, Inbred Strains; D013563:Sympathectomy, Chemical
D006892:Hydroxydopamines; D010643:Phenoxybenzamine; D016627:Oxidopamine; D009638:Norepinephrine; D011224:Prazosin