Jkl. Walker et Db. Jennings, VENTILATORY AND METABOLIC EFFECTS OF HYPERCAPNIA IN CONSCIOUS RATS - AVP V-1 RECEPTOR BLOCK, Canadian journal of physiology and pharmacology, 76(4), 1998, pp. 361-366
In conscious dogs, arginine vasopressin (AVP) inhibits an angiotensin
II drive to ventilation during air breathing and during acute hypercap
nia. To determine whether AVP inhibits respiration in rats, as in dogs
, respiration and metabolism were measured in six male Sprague-Dawley
rats using a plethysmograph. Rats breathed air, followed by 5% and 6.5
% CO2 with or without AVP V-1 receptor block. In unblocked experiments
, minute ventilation (V) over dot increased to a comparable level duri
ng inhalation of both CO, gas mixtures, resulting in a flattening of t
he ventilatory response to increased Pace,. However, oxygen consumptio
n decreased during 6.5% CO2, compared with 5% CO,, so that the ventila
tory equivalent for O-2 increased in a more linear manner with respect
to Pace,. The main effect of AVP V, receptor block was to increase me
an arterial blood pressure; there was no significant effect of AVP V,
receptor block on respiratory responses. AVP does not inhibit respirat
ion in conscious rats as it does in conscious dogs.