Efficacy of bypass between extracerebral artery and cerebral vein with retrograde verapamil infusion into focal cerebral ischemic tissue in rats.

We examined the efficacy of a bypass from an extracerebral artery to a cerebral vein (EA-CV) with retrograde verapamil infusion on acute focal cerebral ischemia in 35 rats. In 12 rats, within 1 hour after occlusion of the middle cerebral artery (MCAO), changes in blood-brain barrier permeability were examined by [14C]alpha-aminoisobutyric acid autoradiography after EA-CV bypass surgery; there were no significant changes during a period of 2 hours after EA-CV bypass. The other 18 rats having MCAO were divided into three groups of six each. Group A rats (control) underwent only cannulation of the cerebral vein. Group B rats had an EA-CV bypass. Group C rats received verapamil (0.1 mg/kg every 2 h) by transvenous perfusion of the brain (TVPOB) through the EA-CV bypass. In all rats in Groups A and C, local cerebral blood flow (LCBF) and quantitative measurement of early cerebral infarct volume were performed by autoradiography using [14C]iodoantipyrine and histochemical staining methods. Group B rats were examined only with the LCBF measurement. Group B (EA-CV bypass only) showed a nonsignificant improvement (18-40%) of LCBF in the ischemic cerebral cortical areas as compared with control Group A. Group C (EA-CV bypass with TVPOB with verapamil) showed an extensive and significant improvement in LCBF in the ischemic cortical areas (115-140%; P less than 0.05) and a slight increase in LCBF in the subcortical areas (17-29%), with a significant reduction (greater than 35%; P less than 0.05) in a total cerebral infarct volume in the ischemic cerebral hemisphere as compared with the control Group A.(ABSTRACT TRUNCATED AT 250 WORDS)