Importance of circulating angiotensin II for elevation of arterial pressure during acute hypercapnia in anaesthetized dogs.

Abstract

1. In anaesthetized dogs acute hypercapnia produced by ventilation with 10% CO2 in air caused release of vasoactive substances and changes of arterial pressure. Catecholamines, angiotensin II, bradykinin and prostaglandin‐like substances were bioassayed continuously in arterial blood using the blood‐bathed organ technique of Vane. 2. Acute hypercapnia in control dogs causes responses of rat stomach strip, chick rectum and rat colon indicating initial release of noradrenaline, followed by angiotensin II, and occasionally release of prostaglandin‐like substances into the circulation. 3. The initial transient, pressor response to hypercapnia coincided with the appearance of noradrenaline, and t..