NMDA and dopamine D2L receptor interaction in human neuroblastoma SH-SY5Y cells involves tyrosine kinase and phosphatase.

Blockade of N-methyl-D-aspartate (NMDA) receptors by the specific antagonists dizocilpine and (+/-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid on human neuroblastoma SH-SY5Y cells expressing human D21 receptors resulted in a significant increase in the density of D2L receptors. In order to understand the mechanism of dopamine D2L receptor induction following NMDA receptor blockade we used specific protein tyrosine kinase and phosphatase inhibitors to demonstrate their involvement in this interaction. The induction of dopamine D2L receptor was measured by radioreceptor binding assay. The density of the dopamine D2L receptor was increased to 109% by the inhibition of protein tyrosine kinase and prevented by the inhibition of phosphatase 1 or 2A. Inactivation of NMDA receptors might effect the phosphorylation-dephosphorylation states of the regulatory proteins and lead to the induction of the D2L receptor gene.