25,715 SNPs that homozygously segregates between P and NP rats. All P rats were homozygous for this stop codon in the mGluR2 receptor ligand-binding domain, whereas none of the NP rats carried this allele. The levels of Grm2 transcript in both striatum and hippocampus were significantly lower, and expression of mGluR2 protein was undetectable in P rats (Fig. 10.2A and B). The loss of the mGluR2 receptor was also consistent with the observation of uncompensated impairment in synaptic depression in P rats, measured as field excitatory postsynaptic potential or population spike in dentate gyrus/hippocampal and striatal slices, upon activation of the receptor by the group II mGluR agonist LY379268.
