Increase in cerebral blood flow in the rabbit by viquidil

The effect of viquidil, an isomer of quinidine, on the cerebral blood flow of the rabbit was determined using the 85 krypton clearance technique. The experimental animals had a thin polyethylene catheter chronically implanted in one of the internal carotid arteries to facilitate injection of the isotope into the cerebral circulation. At the time of the measurements the animals were artificially ventilated to control arterial P CO 2 . Viquidil was administered via the implanted catheter at a dose of 5 mg/kg body weight. Cerebral blood flow was measured before injection of the drug (two control measurements of CBF) and ten minutes and 40 minutes after administration of viquidil. This drug causes an increase in cerebral blood flow of about 50 percent, which lasts at least one hour after administration. This increase in CBF was statistically significant (P < 0.02).