GLUTAMATE-RECEPTOR AGONIST INJECTIONS INTO THE DORSAL STRIATUM CAUSE CONTRALATERAL TURNING IN THE RAT - INVOLVEMENT OF KAINATE AND AMPA RECEPTORS

Unilateral stimulation of glutamate receptors in the dorsal striatum o f intact rats resulted in contralateral turning. Turning behavior was recorded for 20 min following unilateral intrastriatal injections (0.5 mu l) in chronically cannulated rats. Kainate injections caused a dos e-dependent increase in contralateral rotation that was blocked by the glutamate receptor antagonist 6-cyano-7-nitroquinoxaline-2,3-dione (C NQX). the action potential blocker tetrodotoxin, and by increasing dos es of the dopamine receptor antagonist cis-flupenthixol. Injections of lpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA) also c aused rotation that was blocked with co-injections of CNQX, tetrodotox in or cis-flupenthixol. Neither CNQX nor tetrodotoxin injected alone c aused turning. This effect is dopamine-dependent, and may result from a kainate or AMPA-induced increase in dopamine release. Glutamate rece ptor agonist injections into the striatum may cause contralateral turn ing by degrading information in ascending cortical projections and may further influence locomotion via basal ganglia output nuclei projecti ons to the brainstem.