Levemopamil is a novel compound of the phenylalkylamine class of calcium channel blockers, possesses exceptionally high blood-brain barrier penetrability characteristics. It has a potent antagonistic action on serotonin 5-HT2-receptors. Activation of these receptors stimulates inositol phospholipid hydrolysis that can lead to the release of Ca2+ from intracellular stores as well as protein kinase C activation. Levemopamil thus has the potential for blocking deleterious increases of intracellular calcium arising from both intracellular stores and from the extracellular space. Levemopamil reduce both infarct size and extent of neuronal injury following permanent focal or transient global ischemia. The acute effect of bilateral clamping of carotid arteries on local cerebral blood flow was measured in the presence and absence of levemopamil in a separate group of rats. The data suggest that pretreatment with levemopamil reduces impairment in spatial behaviour and that this effect seems not related to the compound's cerebral vasodilatory action, but to direct neuronal mechanisms.