Content of mRNA for NMDA glutamate receptor subunits in the frontal cortex and striatum of rats after morphine withdrawal is related to the degree of abstinence

摘要

We studied the expression of mRNA for genes, whose protein products regulate the glutamate/ NO/cGMP signal cascade in the frontal cortex, striatum, midbrain, and hippocampus of rats with various degrees of spontaneous morphine withdrawal syndrome. The concentration of Grin2a mRNA (subunit of the NMDA glutamate receptor) in the frontal cortex increased mainly in animals with severe abstinence. By contrast, the expression of mRNA for the Grin2b subunit in the striatum decreased in animals with mild abstinence. Variations in the content of mRNA for other products of the cascade (isoforms of NO-dependent guanylate cyclase and cGMP-dependent protein kinase) after morphine withdrawal were not related to the degree of abstinence. Our results suggest that the region-specific expression of mRNA for certain subunits of the NMDA glutamate receptor after morphine withdrawal can determine the degree of abstinence.