Activation of alpha(7) nicotinic acetylcholine receptor promotes survival of spinal cord motoneurons

Spinal cord motoneurons (MNs) undergo a process of cell death during embryonic development [1] and are the target of lethal acquired or inherited disorders, such as the amyotrophic lateral sclerosis, Therefore, the identification of mechanisms leading to MN survival is of crucial importance, Elevations in intracellular Ca2+ promote chicken MN survival during the embryonic period of naturally occurring cell death [2,3]. We have recently demonstrated that the alpha(7) nicotinic acetylcholine receptor (nAChR) mediates significant increases in free Ca2+ concentration at membrane potentials at which other pathways for Ca2+ influx are inactive [4,5], Although it is possible that Ca2+ influx through eel nAChR promotes cell survival, the relation between alpha(7) nAChR activation, cytosolic free Ca2+ and mammalian spinal cord MN survival has not been established, In the present study we have now demonstrated that Ca2+ influx through the alpha(7)-subunit is sufficient to rescue a significant number of cultured spinal cord MNs from programmed cell death induced by trophic factor deprivation. This is the first demonstration that neuronal nAChRs are involved in the regulation of MN survival. (C) 1997 Federation of European Biochemical Societies.