LOCALIZATION OF AMPA GLUTAMATE-RECEPTOR SUBUNITS IN SUBPOPULATIONS OFNONPYRAMIDAL NEURONS IN THE RAT BASOLATERAL AMYGDALA

A two-color immunoperoxidase technique was used to investigate the loc alization of GluR1 and GluR2/3 alpha-amino-3-hydroxy-5-methyl-4-isoxaz ole (AMPA) glutamate receptor subunits in subpopulations of non-pyrami dal neurons in the rat basolateral amygdala. Antibodies to neuropeptid e Y (NPY), vasoactive intestinal peptide (VIP), and calcium binding pr oteins were used to mark three distinct subsets of non-pyramidal cells . Only non-pyramidal neurons containing the calcium binding proteins p arvalbumin (PV) and calbindin D-28k (CB) exhibited robust GluR1-like i mmunoreactivity (GluR1-ir). Light GluR1-ir was observed in some neuron s with NPY-ir and VIP-ir, as well as in some pyramidal cells. Only pyr amidal cells exhibited robust GluR2/3-ir. No significant amount of Glu R2/3-ir was seen in any of the three main classes of non-pyramidal cel ls. These findings indicate that in the rat basolateral amygdala GluR2 /3-ir is found primarily in pyramidal neurons whereas GluR1-ir is foun d mainly in non-pyramidal neurons that contain PV or CB.