GLUTAMATE-RECEPTOR SUBUNITS ASSOCIATED WITH RAT SYMPATHETIC PREGANGLIONIC NEURONS

The purpose of this study was to determine what subunits of the glutam ate (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA)) receptor are expressed by sympathetic preganglionic neurons in the sp inal cord of adult rats. Preganglionic neurons were retrogradely label led with Fluorogold, double-labelled with choline acetyltransferase im munofluorescence, and examined with confocal microscopy for evidence o f immunoreactivity for GluR1, GluR2, GluR2/3 and GluR4 subunits. Quant itative analysis revealed that 92, 63 and 85% of preganglionic cells i n the T8 segment express GluR1, GluR2 and GluR2/3 subunits, respective ly. Cells were not immunoreactive for the GluR4 subunit. This evidence is consistent with the idea that most sympathetic preganglionic neuro ns form heteromeric AMPA receptors. Cells with GluR2 subunits will ass emble receptors which are impermeable to calcium ions and may be resis tant to excitotoxic cell death. (C) 1998 Elsevier Science Ireland Ltd. All rights reserved.