title: Effect of vertebral artery infusions of oxytocin on plasma vasopressin concentration, plasma renin activity, blood pressure and heart rate and their responses to hemorrhage.
abstract: Infusion of oxytocin into one vertebral artery of anesthetized dogs did not alter plasma vasopressin concentration, blood pressure or heart rate. However, there was a significant (p less than 0.01) increase in plasma renin activity (PRA; delta = 7.6 +/- 2.3 ng/ml X h). A 35% hemorrhage caused blood pressure to fall by 9.4 +/- 4.0 mm Hg (p less than 0.01) and PRA to rise by 8.8 +/- 2.7 ng/ml X h (p less than 0.05). In 8 dogs that were subjected to a similar hemorrhage and that also received an intravertebral infusion of oxytocin, blood pressure was maintained and PRA increased by 14 +/- 4.3 ng/ml X h (p less than 0.05). Heart rate and plasma vasopressin responses were similar in both hemorrhage groups. The results indicate that oxytocin prevented the fall in blood pressure associated with a hemorrhage, possibly by increasing renin release.
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001921:Brain / Q000187:drug effects; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects*; D006470:Hemorrhage / Q000097:blood*; D007269:Injections, Intra-Arterial; D008297:Male; D010121:Oxytocin / Q000494:pharmacology*; D011311:Pressoreceptors / Q000187:drug effects; D012083:Renin / Q000097:blood*; D014655:Vascular Resistance / Q000187:drug effects; D014667:Vasopressins / Q000097:blood*; D014711:Vertebral Artery
chemical_list: D014667:Vasopressins; D010121:Oxytocin; D012083:Renin