title: An oxytocin receptor in anococcygeus muscles isolated from male mice.
abstract: The nature of the neurohypophyseal peptide receptor in the anococcygeus muscles from male mice was investigated. The rank order of potency of naturally occurring peptides was oxytocin greater than Arg-vasotocin greater than Arg-vasopressin greater than Lys-vasopressin, which is similar to that found in the uterus and mammary gland. Selective agonists on the oxytocin (OT) receptors of the uterus and mammary gland (Thr4-OT; Gly7-OT; Thr4-Gly7-OT) were also potent agonists in the mouse anococcygeus. Competitive antagonists of uterine responses to oxytocin (dP-TyrMe-Thr4-OT; dP-TyrMe-OT; dP-Thr4-OT; dp-Orn8-OT) were also competitive antagonists of oxytocin-induced contractions of the mouse anococcygeus. It is concluded that the neurohypophyseal peptide receptor of the male mouse anococcygeus is of the oxytocin type; antagonist pA2 values suggest that this receptor resembles, but may not be identical to, the uterine oxytocin receptor. Possible physiological and pharmacological implications of these observations are discussed.
mesh_terms: D000818:Animals; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000378:metabolism*; D010121:Oxytocin / Q000031:analogs & derivatives / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology; D011945:Receptors, Angiotensin / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018045:Receptors, Oxytocin
chemical_list: D010455:Peptides; D011945:Receptors, Angiotensin; D011956:Receptors, Cell Surface; D018045:Receptors, Oxytocin; D010121:Oxytocin