In vivo pharmacological characterization of alpha adrenergic receptors in sheep myometrium and their physiological meaning.
Utero-cervical responsiveness to alpha-adrenergic receptor stimulation was electromyographically evaluated in vivo in adult ovariectomized ewes. Spontaneous motility and drug-induced changes were quantified with a microcomputer. Our results suggested that the two activity patterns previously described on the ovine genital tract could be respectively controlled by alpha-2 and alpha-1 adrenergic mechanisms. Alpha-2 receptors could be assigned to a chronotropic function by activating a hypothetical zone triggering the outbreak of discrete episodes of motility (regular activity); this function is apparent at the cervix even in the absence of estrogen priming. On the other hand, alpha-1 receptors could be assigned to an inotropic function, regulating mainly the magnitude of estrogen-dependent utero-cervical motility (irregular activity).
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007700:Kinetics; D009215:Myometrium / Q000187:drug effects / Q000502:physiology*; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*; D012756:Sheep; D014590:Uterine Contraction / Q000187:drug effects
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D011942:Receptors, Adrenergic, alpha; D004958:Estradiol