Opening of the blood-brain barrier by acute elevation of intracarotid pressure.

A method for local opening of the blood-brain barrier in the territory of one internal carotid artery in the rat is described. A local hypertensive insult is induced by rapid infusion of blood into the internal carotid via the external carotid. The hemodynamic changes caused by the infusion, in particular relation to the threshold and extent of barrier opening, are analyzed. This mode of hypertensive barrier opening may be advantageous to those in which the insult is induced systematically, especially when studying the cerebrovascular effects of neurotransmitter catecholamines, since all the latter methods interfere with adrenergic mechanisms. Further, unilateral intracarotid infusion may allow the territory of the contralateral middle cerebral artery to be used as internal control.