Differential expression of excitatory amino acid receptor subtypes in cultured cerebellar neurons

Using neurotoxicity and inositol phosphate release as criteria for receptor expression, we report the differential expression of excitatory amino acid receptor subtypes in cerebellar granule cells grown in serum-free media containing either high (25 mM) or low (5 mM) KCl. NMDA receptors are expressed in neurons grown in high, but not low, KCl. In contrast, ionotropic quisqualate receptors are expressed in neurons grown in low KCl, but not in those grown in high KCl. Addition of NMDA to cultures containing low KCl appears to mimic high KCl conditions: NMDA receptors are expressed, but ionotropic quisqualate receptors are not. Glutamate and kainate are toxic to cells grown in either condition.