The effects of transient cerebral ischemia on vasopressin-induced vasoconstriction in rabbit cerebral vessels.

Background: Vasopressin is a drug of choice for use during cardiopulmonary resuscitation because several experimental studies have shown that it is better than epinephrine at increasing systemic perfusion pressure and improving cerebral perfusion pressure without increasing myocardial oxygen consumption. We used a pial window preparation to determine the effects of vasopressin when applied topically to pial vessels and whether any effects were altered after cerebral ischemia in rabbits (n = 27).

Methods: We first examined the effects of topical application of arginine-vasopressin (AVP) (10(-11) M, 10(-9) M, 10(-7) M, and 10(-5) M, sequentially).

The comparative effects of intravenous nicardipine and prostaglandin E1 on the cerebral pial arteriolar constriction seen after unclamping of an aortic cross-clamp in rabbits.

Background: The potent vasodilators nicardipine and prostaglandin E1 (PGE1) are useful for the treatment of systemic hypertension or pulmonary hypertension during aortic surgery.

Methods: We measured cerebral pial arteriolar diameters, using a rabbit closed cranial window preparation: before (baseline) and 15 min after the start of an IV infusion (preclamp) (0.9% saline [control group], nicardipine [at 0.

Both milrinone and colforsin daropate attenuate the sustained pial arteriolar constriction seen after unclamping of an abdominal aortic cross-clamp in rabbits.

We previously reported that unclamping of an abdominal aortic cross-clamp causes initial dilation of pial arteries followed by sustained constriction. Both milrinone and colforsin daropate have a vasodilator action, and both have been used in such critical conditions as abdominal aortic aneurysmectomy. We measured cerebral pial arteriolar diameters using a rabbit closed cranial window preparation before (baseline) and 15 min after the start of an IV infusion of 0.

Intrathecal neostigmine prevents intrathecal clonidine from attenuating hypercapnic cerebral vasodilation in rabbits.

We previously demonstrated that lumbar intrathecal alpha(2) agonists attenuate hypercapnia-induced cerebral vasodilation. The combination of intrathecal clonidine and neostigmine is being investigated as pain therapy. The effects of their combination on cerebrovascular reactivity are unknown.