Vasoactive intestinal polypeptide (VIP): effect on rabbit uterine smooth muscle in vivo and in vitro.
The effect of vasoactive intestinal polypeptide (VIP) on uterine smooth muscle electrical and mechanical activity in non-pregnant estradiol-treated rabbits was investigated using in vivo and in vitro methods. The studies were performed on spontaneous, oxytocin-, carbachol-, and prostaglandin-42 alpha-induced activity. VIP had a dose-related inhibitory effect on both myoelectrical and mechanical activity. The concentration needed for 50% inhibition (ID50) was 2 x 10(-10) mol VIP . 1(-1) (in vivo), an 6 x 10(-8) mol VIP . 1(-1) (in vitro). This inhibition was unaffected by the presence of atropine (10(-5) mol . 1(-1)), propranolol (10(-5)), phentolamine (10(-5)), naloxone (10(-5)), apamin (10(-5)), and tetrodotoxin (10(-5)). These findings indicate that VIP may act via a specific receptor on the smooth muscle and supports the hypothesis that VIP may be a neurotransmitter involved in the local nervous control of uterine smooth muscle activity.
D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002217:Carbachol / Q000494:pharmacology; D015237:Dinoprost; D005071:Evoked Potentials / Q000187:drug effects; D005260:Female; D005768:Gastrointestinal Hormones / Q000494:pharmacology*; D009130:Muscle, Smooth / Q000187:drug effects*; D010121:Oxytocin / Q000494:pharmacology; D011460:Prostaglandins F / Q000494:pharmacology; D011817:Rabbits; D013565:Sympatholytics / Q000494:pharmacology; D014590:Uterine Contraction / Q000187:drug effects; D014599:Uterus / Q000187:drug effects; D014660:Vasoactive Intestinal Peptide / Q000494:pharmacology*
D005768:Gastrointestinal Hormones; D011460:Prostaglandins F; D013565:Sympatholytics; D014660:Vasoactive Intestinal Peptide; D010121:Oxytocin; D001285:Atropine; D002217:Carbachol; D015237:Dinoprost