Vasopressin prolongs bradycardiac response during orientation.
Adult male rats were implanted with transcutaneous ECG electrodes and habituated to a dark chamber with elevated background noise levels. ECG was recorded prior to, immediately after, and 3 min after sudden elimination of background noise. The orienting response to the stimulus offset was accompanied by transient bradycardia. Neither AVP (1 microgram/rat) nor oxytocin (1 microgram/rat) injected subcutaneously 1 hr prior to testing altered baseline heart rate or the immediate bradycardiac response to stimulus offset. However, AVP, and to a lesser extent oxytocin, prolonged the bradycardia induced by stimulus offset. The results show that neurohypophyseal peptide hormones enhance the cardiovascular component of orienting to stimulus change.
D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology*; D001143:Arousal / Q000187:drug effects*; D004562:Electrocardiography; D006185:Habituation, Psychophysiologic / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D009949:Orientation / Q000187:drug effects*; D010121:Oxytocin / Q000494:pharmacology; D051381:Rats
D001127:Arginine Vasopressin; D010121:Oxytocin