Role of heat shock proteins in the effect of NMDA and KCl on cerebellar granule cells survival

Cerebellar granule cells (CGC) die apoptotically after five days in culture (DIV) at physiological concentrations of potassium (5 mM; K5). When CGC ar e depolarized (K25) or treated with NMDA (150 mu M) cell survival is increa sed. CGC changed from K25 to K5 die after 24-48 h. It is known that heat sh ock protein (HSP) may protect from cell death. Here, we found that cells in K5 showed an increase in HSP-70 levels after 3 DIV. Similarly, in cells ch anged from K25 to KS, HSP-70 levels were increased after 6 h. Neither NMDA nor K25 treatment affected HSP-70 levels from 2-7 DIV. Ethanol or thermal s tress induced HSP-70, but cell survival was not affected in K5 medium. Thes e results suggest that HSP, particularly HSP-70, are not involved in the me chanisms by which NMDA and KCl promote cell survival.