[Effect of KB-2796, a novel calcium channel blocker, on spreading depression in rat hippocampal slices].

KB-2796, a novel calcium channel blocker, is under development as an anti-migraine drug. We examined its effects on spreading depression (SD) in rat hippocampal slices as compared with those of flunarizine, dimetotiazine and sumatriptan. Extracellular recording was made from the CA1 subfield. An SD, followed by a series of spontaneous SDs, was induced by a brief period of hypoxia (40-60 sec). The latency of initiated SD and the interval between the initiated and subsequent spontaneous SDs were examined. KB-2796 significantly prolonged both latency and interval in a concentration-dependent manner (10(-10)-10(-8) M). KB-2796 was about 1,000 and 10 times more potent than flunarizine in prolonging the latency and interval, respectively. However, dimetotiazine and sumatriptan did not show any activity at 10(-7) and 10(-6) M. the effect of KB-2796 on SD may be due to their calcium channel blocking effects.