Effect of some iono- and metabotropic glutamatergic ligands on neuropeptide Y immunoreactivity in the rat hippocampus.

The effect of some agonists and antagonists of glutamatergic receptors (GluR) on neuropeptide Y (NPY) level in the rat hippocampus was investigated using radioimmunoassay method. The compounds were injected intraperitoneally (NMDA, ACPC and MPEP) or intrahippocampally (L-CCG, L-SOP, AIDA). It was found that NMDA induced a decrease in NPY-IR in the hippocampus. No significant changes were found after ACPC (a functional NMDA receptor antagonist) and MPEP (mGlu5 receptor antagonist). NPY-IR was significantly increased after intrahippocampal injections of group II and III mGluR agonists (L-CCG-I and L-SOP, respectively), as well as after group I mGluR antagonist AIDA. The obtained results indicate that glutamatergic metabotropic and NMDA receptors may regulate NPY expression in the hippocampus. This regulation may have some connection with modulation of anxiety by the studied compounds.