SELECTIVE ROLE OF N-TYPE CALCIUM CHANNELS IN NEURONAL MIGRATION

Analysis of neuronal migration in mouse cerebellar slice preparations by a laser scanning confocal microscope revealed that postmitotic granule cells initiate their migration only after the expression of N-type calcium channels on their plasmalemmal surface. Furthermore, selective blockade of these channels by addition of omega-conotoxin to the incubation medium curtailed cell movement. In contrast, inhibitors of L- and T-type calcium channels, as well as those of sodium and potassium channels, had no effect on the rate of granule cell migration. These results suggest that N-type calcium channels, which have been predominantly associated with neurotransmitter release in adult brain, also play a transient but specific developmental role in directed migration of immature neurons before the establishment of their synaptic circuits.