Effect of Pharmacological Modulation of Activity of Metabotropic Glutamate Receptors on Their Gene Expression after Excitotoxic Damage in Hippocampal Neurons.

Microinjection of kainic acid into rat hippocampus causes excitotoxic neuronal damage predominantly in the CA3 and CA1 fields. These lesions can be significantly reduced by simultaneous administration of MPEP, a negative allosteric modulator of type 5 metabotropic glutamate receptors, and LY354740, an agonist of type 2 metabotropic glutamate receptors. The decrease in neuronal death in the hippocampus during pharmacological modulation was paralleled by adaptive changes in gene expression. In the hippocampus, gene expression of type 5 postsynaptic metabotropic glutamate receptor was close to the control level, and in the frontal cortex expression of the gene of α-subunit of the GABAA receptor returned to normal. In the frontal cortex, a reciprocal relationship was observed for type 2 metabotropic glutamate receptor: expression of the corresponding gene decreased in response to pharmacological activation.