MOLECULAR AND FUNCTIONAL-PROPERTIES OF METABOTROPIC GLUTAMATE RECEPTORS IN THE BRAIN

We examined the molecular structural and functional properties of meta botropic glutamate receptors (mGluRs) in rat brains, especially the su btypes 1 and 5 which are known to stimulate phosphoinositide (PI) meta bolism. We found that mGluR5 as well as mGluR1 has structural variants , most likely derived by the alternative splicing of the gene. We also found that, under certain circumstances, mGluR1 could inhibit, instea d of stimulate, PI turnover in a G protein-dependent manner. This find ing may give a possible explanation for the discrepancy we observed be tween the postnatal development of glutamate-stimulated PI turnover an d the postnatal ontogenesis of mGluRs.