title: Central oxytocin modulation of acute stress-induced cardiovascular responses after myocardial infarction in the rat.
abstract: The present study was aimed at determining the role of centrally released oxytocin in regulation of blood pressure and heart rate (HR) under resting conditions and during an acute air-jet stress in rats with a myocardial infarction and controls infarcted. Four weeks after ligation of a coronary artery or sham surgery, conscious Sprague Dawley rats were subjected to one of the following intracerebroventricular (ICV) infusions: (1) 0.9% NaCl (control), (2) oxytocin, (3) oxytocin receptor antagonist {desGly-NH(2)-d(CH(2))(5)[D-Tyr(2)Thr(4)]OVT}(OXYANT). Resting arterial blood pressure and HR were not affected by any of the ICV infusions either in the infarcted or sham-operated rats. In the control experiments, the pressor and tachycardic responses to the air jet of infarcted rats were significantly greater than in the sham-operated rats. OXYANT significantly enhanced the cardiovascular responses to stress only in the sham-operated rats whereas oxytocin significantly attenuated both responses in the infarcted but not in the sham-operated rats. The results suggest that centrally released endogenous oxytocin significantly reduces the cardiovascular responses to the acute stressor in control rats. This buffering function of the brain-oxytocin system is not efficient during the post-myocardial infarction state, however it may be restored by central administration of exogenous oxytocin.
authors.affiliation: Department of Experimental and Clinical Physiology, Medical University of Warsaw, Warsaw, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Wsół
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Cudnoch-Je drzejewska
authors.forename: Ewa
authors.initials: E
authors.lastname: Szczepanska-Sadowska
authors.forename: Stanisław
authors.initials: S
authors.lastname: Kowalewski
authors.forename: Jakub
authors.initials: J
authors.lastname: Dobruch
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects*; D007276:Injections, Intraventricular; D008297:Male; D009203:Myocardial Infarction / Q000503:physiopathology*; D009951:Ornipressin / Q000031:analogs & derivatives / Q000494:pharmacology; D010121:Oxytocin / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018045:Receptors, Oxytocin / Q000037:antagonists & inhibitors; D013312:Stress, Physiological
chemical_list: D018045:Receptors, Oxytocin; C074541:vasotocin, desGly(NH2)(9)d(CH2)5-Tyr(Me)(2)-Thr(4)-Orn(8)-; D009951:Ornipressin; D010121:Oxytocin