Glycine potentiates the stimulation of inositol phospholipid hydrolysis by excitatory amino acids in primary cultures of cerebellar neurons.

Glycine potentiates stimulation of inositol phospholipid hydrolysis by glutamate and N-methyl-D-aspartate, but not by quisqualate or carbamylcholine, in primary cultures of cerebellar granule cells. This potentiation occurs in the absence of extracellular Mg2+, but is more evident when stimulation of inositol phospholipid hydrolysis by N-methyl-D-aspartate is measured in the presence of 1 mM Mg2+. The action of glycine is not antagonized by strychnine. These results suggest that glycine acts as a positive modulator of signal transduction at a specific class of N-methyl-D-aspartate-sensitive glutamate receptors coupled to inositol phospholipid hydrolysis in cerebellar granule cells.