Pressor response to chemoreflex activation in awake rats: role of vasopressin and adrenal medulla.
The possible role of the peptide vasopressin and adrenal catecholamine in the pressor response to chemoreflex activation was evaluated in awake rats. Data show that the peripheral blockade of the V1 vasopressin receptor produced no change in the cardiovascular responses to chemoreflex activation, indicating that vasopressin plays no role on the pressor response to chemoreflex activation. We also have shown that the pressor response to chemoreflex activation is dependent on the sympathetic efferent activity since the antagonism of the alpha1-adrenoceptor with prazosin almost abolished the pressor response to chemoreflex activation. Furthermore, bilateral adrenal demedullation produced no change on the pressor response to chemoreflex activation, outpointing that the release of catecholamines by the adrenal medulla is not involved in the pressor response to chemoreflex. We conclude that the pressor response to chemoreflex activation is essentially mediated by the sympathetic innervations to the peripheral vascular beds.
Fernandes
Luciano G
LG
Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil.
Antunes
Vagner R
VR
Bonagamba
Leni G H
LG
Machado
Benedito H
BH
D000313:Adrenal Medulla / Q000187:drug effects / Q000502:physiology*; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D001522:Behavior, Animal; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology*; D002319:Cardiovascular System / Q000187:drug effects; D002395:Catecholamines / Q000378:metabolism; D002628:Chemoreceptor Cells / Q000187:drug effects / Q000502:physiology*; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D008297:Male; D010456:Peptides, Cyclic / Q000494:pharmacology; D011190:Potassium Cyanide / Q000494:pharmacology; D011224:Prazosin / Q000494:pharmacology; D051381:Rats; D017208:Rats, Wistar; D012018:Reflex / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D014443:Tyrosine / Q000031:analogs & derivatives* / Q000494:pharmacology; D014667:Vasopressins / Q000037:antagonists & inhibitors / Q000502:physiology*; D014851:Wakefulness / Q000502:physiology*
D000317:Adrenergic alpha-Antagonists; D002395:Catecholamines; D004791:Enzyme Inhibitors; D010456:Peptides, Cyclic; C433483:Tyr(Me)-AVP; D014667:Vasopressins; D014443:Tyrosine; D011190:Potassium Cyanide; D011224:Prazosin