Different coupling of excitatory amino acid receptors with Ca2+ channels in primary cultures of cerebellar granule cells.

Cerebellar granule cells in primary culture express receptors for excitatory amino acids. The activation of these receptors results in an increased uptake of Ca2+, however, the effects are different depending on the agonists used. Aspartate, NMDA and ibotenate are active only in depolarized conditions, whereas kainate and glutamate activate Ca2+ uptake independently from depolarization. The results indicate the presence of two receptor types: kainate recognition site coupled with voltage-independent Ca2+ channels and NMDA recognition site coupled with voltage-dependent Ca2+ channels.