EXPRESSION PATTERN AND PHARMACOLOGY OF THE RAT TYPE-IV METABOTROPIC GLUTAMATE-RECEPTOR

The mRNA for the type IV metabotropic glutamate receptor (mGluR4) is m ost prominently expressed in cerebellar granule cells, the olfactory s ystem, the lateral septal nucleus, and most thalamic nuclei, but lower amount of the mRNA is found in many different brain regions, Agonist stimulation as studied in transfected cells was found to inhibit forsk olin-stimulated cyclic-adenosine-monophosphate formation through a per tussis toxin-sensitive mechanism. Agonist rank order of potencies was: L-2-amino-4-phosphonobutyrate (L-AP4) > glutamate > (1S,3R)-1-aminocy clopentane-1,3-dicarboxylic acid (t-ACPD) > quisqualate > L-homocystea te = ibotenate. The results suggests that the mGluR4 may be responsibl e for many, but not all, effects Of L-AP4.