SELECTED P2 PURINOCEPTOR MODULATORS PREVENT GLUTAMATE-EVOKED CYTOTOXICITY IN CULTURED CEREBELLAR GRANULE NEURONS

Primary cultures of granule neurons derived from cerebella of postnata l rats are endowed with Glu receptors. Glu receptor agonists exert a t rophic influence on differentiating granule cells but, with maturation , the cells become vulnerable to excitatory amino acids. Here we show that the P-2 purinoceptor antagonist basilen blue abolishes in rat cer ebellar granule neurons the cytotoxic action of glutamate with an IC50 in the 10-20 mu M range. Within the same concentrations, basilen blue inhibits binding of [H-3] ATP to cerebellar granule cells, glutamate- evoked release (but not uptake) of [H-3] D-aspartate and Ca2+ uptake. Furthermore, the extracellular phosphorylation of a major 45-kDa endog enous ecto-protein substrate of cerebellar granule neurons is inhibite d with an IC50 of about 1 mu M. Similar effects are elicited by 5-aden ylylimidodiphosphate, a P-2 purinoceptor agonist, when supplied to the neurons for 8 days previously to the addition of glutamate. Our data point to the use of P-2 purinoceptor modulators as novel elements for understanding and controlling glutamate-mediated excitatory neurotoxic ity and neurotransmission. We suggest a possible involvement of P-2 pu rinoceptors in these actions. (C) 1996 Wiley-Liss, Inc.