Dopamine-glutamate interaction in rat striatal slices: changes of CCDPK II, PKA, and LDH activity by receptor-mediated mechanisms

AIM: To Study the effects of dopamine (DA) and glutamate (Glu) and their re ceptor agonists/antagonists on Ca2+/calmodulin-dependent protein kinase IT (CCDPK II), cyclic AMP-dependent protein kinase A (PKA) activities and the: LDH release in rat striatal slices, and to examine the interaction between DA and Glu transmitter systems in: striatum. METHODS: The activities of CCD PK II, PKA, and the release of LDH were determined with the (32) P-incorpor ation and colorimetry respectively in rat striatal slices. RESULTS: (1) Exo genous DA, D-1 receptor agonist SKF 38393 and D-2 receptor agonist LY 17155 5 reduced CCDPK II activity in striatal slices;:Glu also inhibited CCPPK II activity in a concentration-dependent manner. NMDA receptor antagonist MK- 801 could-antagonize the inhibitory effect of SKF 38393 and:LY171555 on the CCDPK II activity. DI and D-2 receptor antagonists SCH 23390 and spiperone could also antagonize the decrease of CCDPK II activity induced by Glu; (2 ) DA and SKF 38393 markedly increased PKA activity in striatal slices, whic h was reduced by MK-801; (3) DA and Glu increased the release of LDH from t he striatal neurons in a concentration-dependent manner. MK-801 antagonized the increase of LDH induced by DA. Spiperone, rather than SCH 23390, could reduce the release of LDH from striatal neuron in the presence of Glu. CON CLUSION: The interaction between DA and Glu transmitter systems is found in the regulation of the CCDPK Il and PKA activities and cell function in the striatum.