DIFFERENTIAL EXPRESSION OF GROUP-I METABOTROPIC GLUTAMATE RECEPTORS (MGLURS) IN THE RAT PHEOCHROMOCYTOMA CELL-LINE PC12 - ROLE OF NERVE GROWTH-FACTOR AND RAS

Glutamate treatment of PC12 cells has been shown to result in the accu mulation of intracellular inositol phosphates suggesting the presence of glutamate metabotropic receptors (mGluRs) positively coupled to pho spholipase C. The present study examined the expression of group I mGl uRs (mGluR1 and mGluR5) in PC12 cells. Undifferentiated PC12 cells wer e found to express both mGluR5 mRNA and receptor protein by reverse tr anscription polymerase chain reaction (RT-PCR) and western blot techni ques. However, mGluR1 mRNA was not detected in these cells and western blot analysis showed only faint mGluR1 alpha immunoreactivity suggest ing a very low level of mGluR1 expression. Nerve growth factor-induced differentiation of PC12 cells resulted in the induction of mGluR1 alp ha and mGluR1 beta mRNA and mGluR1 alpha protein. PC12 cells overexpre ssing dominant negative ras revealed that NGF-induced mGluR1 induction , but not mGluR5 expression, is dependent on ras pathway activation in these cells. These results suggest PC12 cells may be a useful model f or investigating the regulation and expression of group I mGluR isofor ms and their role in neuronal processes in vitro. (C) 1998 Elsevier Sc ience Ireland Ltd. All rights reserved.