Contralateral Turning Caused by Metabotropic Glutamate Receptor Stimulation in the Dorsal Striatum Is Reversed by MCPG, TTX, and cis-Flupenthixol

Recent evidence suggests an involvement of metabotropic glutamate receptors in the physiology of the striatum. In this study, rotation was recorded in an automated rotometer for 20 min following dorsal striatal injections (0.5 μl) in cannulated rats. The metabotropic agonist 1-aminocyclopentane-trans-1, 3-dicarboxylic acid (1S, 3R-ACPD) caused dose-dependent contralateral rotation. Turning caused by 500 μM 1S, 3R-ACPD was reversed by coinjections of the metabotropic antagonist +-alpha-methyl-4-carboxyphenylglycine (MCPG, 1 mM) and by tetrodotoxin (100 μM). Injections of MCPG alone (10 μM, 100 μM, 1 mM) failed to elicit turning. Increasing doses of the dopamine antagonist cis-flupenthixol also reversed 1S, 3R-ACPD-induced rotation. Thus unilateral striatal metabotropic glutamate receptor stimulation can cause receptor-specific rotation that may result from an increase in neural activity, and is dependent on intact dopamine neurotransmission.