IN-SITU HYBRIDIZATION ANALYSIS OF SUBSTANCE-P RECEPTOR IN THE RAT RETINA

Substance P receptor is known to provide a principal interface between tachykinin peptides and tachykinin-sensitive cells in retinal circuit ry and to produce several physiological functions such as excitation o f ganglion cells. We reported results of in situ hybridization analysi s of substance P receptor in rat retina using digoxigenin-labeled RNA probes to yield discrete cell labeling. Distinct hybridization signal was present in a great majority of ganglion cells that provide retinal fibers to a central target. It was also present in a subpopulation of amacrine cells. Following optic nerve crush, ganglion cells lost thei r hybridization signal in a time-dependent manner, while hybridization -positive amacrine cells were persistently seen. From the results, we identified the hybridization message as distinctly localized to two sy stems, output cells and intrinsic cells in retinal circuitry.