Interaction of AT1 receptors and V1a receptors-mediated effects in the central cardiovascular control during the post-infarct state.
Experimental objectives. Because myocardial infarct is associated with overactivation of brain angiotensin II (ANG II) and vasopressin (AVP) V1a receptors we decided to determine whether AT1 and V1a receptors-mediated effects of ANG II and AVP interact in central cardiovascular control during the post-infarct state. Four groups of infarcted and four groups of sham-operated conscious rats entered the study. Results. In the infarcted rats cerebroventricular infusion of AT1 (AT1ANT, losartan) and V1a antagonist {V1aANT,d(CH(2))(5)[Tyr(Me)(2)Ala-NH(2)(9)]VP} and combined infusion of both these compounds performed 4 weeks after induction of the infarct significantly and comparably reduced mean arterial blood pressure (MABP) in comparison to control experiments (artificial cerebrospinal fluid infusion). In the sham rats MABP was not affected by any of the infusions. In control experiments MABP and HR responses to an alarming air jet stress were significantly higher in the infarcted than in the sham rats. Both responses were normalized with the same effectiveness by administration of AT1ANT, V1aANT and AT1ANT+V1aANT. In the sham rats administration of these compounds did not affect MABP and HR responses to stress.


CONCLUSIONS
The results provide evidence for interaction of AT1 and V1a receptors-mediated effects of ANG II and AVP in the central cardiovascular control during the post-infarct state.
Cudnoch-Jedrzejewska
Agnieszka
A
Department of Experimental and Clinical Physiology, Medical University of Warsaw, Krakowskie Przedm. 26/28 Street, Warsaw 00-927, Poland.
Dobruch
Jakub
J
Puchalska
Liana
L
Szczepańska-Sadowska
Ewa
E
D047228:Angiotensin II Type 1 Receptor Blockers / Q000008:administration & dosage; D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000008:administration & dosage / Q000031:analogs & derivatives; D001794:Blood Pressure / Q000187:drug effects; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002319:Cardiovascular System / Q000378:metabolism* / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects; D007276:Injections, Intraventricular; D019808:Losartan / Q000008:administration & dosage; D008297:Male; D009203:Myocardial Infarction / Q000378:metabolism* / Q000503:physiopathology; D051381:Rats; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism*; D017483:Receptors, Vasopressin / Q000378:metabolism*; D013312:Stress, Physiological / Q000378:metabolism / Q000503:physiopathology
D047228:Angiotensin II Type 1 Receptor Blockers; D065092:Antidiuretic Hormone Receptor Antagonists; D044140:Receptor, Angiotensin, Type 1; D017483:Receptors, Vasopressin; C090290:argipressin, beta- mercapto-beta,beta-cyclopentamethylenepropionic acid-Tyr(Me)(2)-Ala-NH2(9)-; D001127:Arginine Vasopressin; D019808:Losartan