Reflex effects of thoracic aorta wall stretch on regional vascular resistance.

Abstract

In anesthetized, vagotomized cats with both carotid arteries occluded, a stretch of the walls of the thoracic aorta, performed without obstructing aortic flow, induced a significant reflex increase in arterial pressure (35 +/- 2-26 +/- 1 mmHg; systolic-diastolic). This pressure increase was accompanied by significant increases in peripheral resistance in the superior mesenteric (+30%), renal (+23%), and external iliac (+23%) vascular beds. The increase in iliac resistance observed in the skinned leg was comparable with that observed in the contralateral intact limb. All these vascular responses were drastically reduced by the administration of phenoxybenzamine. After alpha-adrenergic blockade no signs of reflex vasodilatation could be detected during aortic stretch in any of the vascular beds examined.