Intrastriatal injection of the metabotropic glutamate receptor antagonist MCPG attenuates acute amphetamine-stimulated neuropeptide mRNA expression in rat striatum.

摘要

In chronically cannulated rats, microinjection of a competitive metabotropic glutamate receptor (mGluR) antagonist, (+)-alpha-methyl-4-carboxyphenylglycine (MCPG), into the dorsal striatum at doses of 0.4, 2 and 10 micrograms/1 microliter did not affect basal levels of preprodynorphin, substance P and preproenkephalin mRNAs in the dorsal striatum as revealed by quantitative in situ hybridization. However, intrastriatal MCPG (0.08, 0.4 and 2 micrograms/1 microliter) dose-dependently attenuated increases in the three mRNA expression induced by acute amphetamine injection (2 mg/kg, i.p.). MCPG had no significant effect on spontaneous, and amphetamine-stimulated, behavioral activities. These data indicate that activation of MCPG-sensitive mGluRs is necessary for upregulation of striatal neuropeptide mRNA expression in response to amphetamine exposure. However, the mGluR activity is not implicated in maintaining basal levels of the peptide gene expression in the striatum.