Spreading depolarization waves triggered by vagal stimulation in the embryonic chick brain: Optical evidence for intercellular communication in the developing central nervous system

Throughout experiments on multiple-site voltage-sensitive dye recordings of neural activity in embryonic chick brain preparations, we have found a nov el type of depolarization waves which spt ead widely from the brainstem to the whole brain region at a rapid rate (mm/s). This depolarization wave was triggered by glutamate-mediated postsynaptic potentials and was especially correlated to N-methyl-D-aspartate receptor function. Evidence that the sp reading depolarization wave is eliminated by octanol or 18 beta -glycyrrhet inic acid suggests that the depolarization wave depends on functions of gap junctions. The profile obtained with Ca2+-imaging experiments also suggest s that the propagation of the depolarization wave is accompanied by a calci um wave. These results provide new evidence for intercellular functional communicati on between neural cells in the vertebrate central nervous system during emb ryonic development. (C) 2001 IBRO. Published by Elsevier Science Ltd. All r ights reserved.