Changes in mRNA levels for group I metabotropic glutamate receptors following in utero hypoxia-ischemia

The expression of group I metabotropic glutamate receptors (mGluR1 and mGlu R5) and inositol 1,4,5-trisphosphate receptor type 1 (IP(3)R1) mRNA was stu died by in situ hybridization in the developing rat hippocampus after in ut ero hypoxia-ischemia. In utero hypoxia-ischemia was induced by clamping the uterine blood vessels of near-term fetuses for 10 min. Fetuses were delive red surgically, resuscitated and raised by foster mothers until postnatal d ay 7 and 14. Results indicated a temporal delay in the expression of mGluR1 mRNA in the dentate gyrus of the ischemic animals. The mGluR1 mRNA level w as significantly lower in the ischemic animals at postnatal day 7, but reac hed a similar level as that of controls at postnatal day 14. In utero hypox ia-ischemia did not change the temporal-spatial expression pattern of eithe r mGluR5 or IP(3)R1 mRNA in the hippocampus. Between postnatal day 7 and 14 , mGluR5 mRNA showed a high and relatively constant expression, whereas IP3 R1 mRNA levels were increased in all regions examined. The differences in t he expressions of group I mGluRs indicate that these receptors may have dif ferent functions during hippocampal development and may play different role s in excitotoxicity. (C) 1999 Elsevier Science B.V. All rights reserved.