Effect of chronic glutamate administration to pregnant rats during gestation on metabotropic glutamate receptors from mothers and full-term fetuses brain

Summary.

Chronic glutamate treatment during gestational period caused a significant decrease in total metabotropic glutamate receptors (mGluR) number. Similar results were observed on the steady-state level of mGlu₁ receptor detected by immunoblotting assays, suggesting that this is the main receptor subtype modulated by agonist exposure. Furthermore, no variations on mRNA coding mGlu₁ receptor were found, suggesting post-transcriptional modulation as a possible mechanism of the lost of receptor detected at the membrane surface. On the other hand, western-blotting to determine level of G_q/11 protein and phospholipase C β₁ revealed a significant decrease of both proteins in mothers brain. This decrease was associated with significant variation in glutamate and DHPG-stimulated phospholipase C activity. No significant differences on mGluR transduction pathway components were observed in fetuses brain. These results suggest that glutamate intake during pregnancy causes a down-regulation of different proteins involved in glutamate response mediated by mGluR only in mothers brain without significantly affecting fetuses brain.