title: During acute hypercapnia vasopressin inhibits an angiotensin drive to ventilation in conscious dogs.
abstract: Intravenous infusion of arginine vasopressin (AVP) depresses the slope of the ventilatory response to CO2 during acute hypercapnia. We therefore tested the hypothesis that AVP V1-receptor blockade would increase the slope of the ventilatory response to CO2. After a 20-min control period, an AVP V1-receptor antagonist (d(CH2)5[Tyr(Me)2]AVP) was injected into six conscious resting dogs. Thirty minutes after AVP V1-receptor blockade, dogs were exposed to sequential 20-min periods of 5 and 6.5% inspired CO2 in air. A second protocol (no AVP V1-receptor blockade) was conducted as a control. As predicted, AVP V1-receptor blockade enhanced ventilation during inhalation of 6.5% CO2 in association with an increased metabolic rate and increased plasma angiotensin II (ANG II). In eupneic dogs, stimulation of respiration by AVP V1-receptor blockade is mediated by ANG II. A third protocol with ANG II-receptor blockade (intravenous infusion of saralasin) combined with AVP V1-receptor blockade indicated that ANG II mediated the increase in metabolism and the augmented ventilation during inhalation of 6.5% CO2. We conclude that during acute hypercapnia of sufficient magnitude, and perhaps duration, AVP inhibits an ANG II-mediated stimulation of metabolism and respiration.
authors.affiliation: Department of Physiology, Queen's University, Kingston, Ontario, Canada.
authors.forename: J K
authors.initials: JK
authors.lastname: Walker
authors.forename: D B
authors.initials: DB
authors.lastname: Jennings
mesh_terms: D000136:Acid-Base Equilibrium; D000208:Acute Disease; D000804:Angiotensin II / Q000378:metabolism / Q000502:physiology*; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage; D000818:Animals; D065092:Antidiuretic Hormone Receptor Antagonists; D001127:Arginine Vasopressin / Q000008:administration & dosage*; D004285:Dogs; D018495:Fluid Shifts / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D006935:Hypercapnia / Q000378:metabolism / Q000503:physiopathology*; D007262:Infusions, Intravenous; D008297:Male; D012083:Renin / Q000097:blood / Q000187:drug effects; D012119:Respiration / Q000187:drug effects* / Q000502:physiology; D012504:Saralasin / Q000008:administration & dosage
chemical_list: D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D065092:Antidiuretic Hormone Receptor Antagonists; D000804:Angiotensin II; D001127:Arginine Vasopressin; D012083:Renin; D012504:Saralasin