Effects of ethanol- and saline-base PGE1 on the canine cerebral circulation.

The effects of ethanol- and saline-base prostaglandin E1 (PGE1) on systemic arterial blood pressure ((ABP), cerebral blood flow (CBF), cerebral vascular resistance (CVR), and cerebrospinal fluid (CSF) pressure were determined in anesthetized dogs. Progressively greater carotid intra-arterial infusions of ethanol-base PGE1 moderately decreased systemic ABP and CVR while perfusion of the CSF system with PGE1 moderately increased ABP and CVR; CBF was unaffected by either route of administration and CSF pressure was constant except for a slight decrease at the lowest intraventricular perfusion rate. Similar infusions of PGE1 were administered in saline base solutions in another group of dogs.

Role of vasoactive substances in active hyperemia in skeletal muscle (38520).

A prolonged, 2-hr period of exercise hyperemia in the canine gracilis muscle was associated with initial increases in the arteriovenous differences for potassium, hydrogen and osmolality. However, that for hydrogen decreased and those for potassium and osmolality became negligible by the 120th min while blood flow remained elevated. Thus, potassium and osmolality do not appear to participate importantly in the maintenance of exercise hyperemia in canine gracilis muscle.