SYMPATHETIC INNERVATION OF THE RATS EYE AND PERIPHERAL GANGLIA - AN ELECTRON-MICROSCOPIC AUTORADIOGRAPHIC TRACING STUDY

The sympathetic innervation of the rat anterior eye segment and relate d peripheral ganglia was studied using light and electron microscopic autoradiography after anterograde tracing with H-3-leucine from the su perior cervical ganglion. In the trigeminal and pterygopalatine gangli a, unmyelinated nerve fibers were labeled. Some fibers contained accum ulations of small vesicles. Close apposition of these labeled sympathe tic fibers with other unmyelinated fibers was common, and was also obs erved at sites where accumulations of vesicles were found. In the iris , cillary body and trabeculum, numerouS fibers and vesicle-containing varicosities were labeled, which all had a similar morphology. No labe ling was found in the cornea. Sympathetic fibers traversing the trigem inal and pterygopalatine ganglion closely appose other unmyelinated fi bers and contain clusters of vesicles without forming classical synapt ic contacts. However, non-synaptic information transfer needs further investigation. The anterior eye segment, except for the cornea, is den sely innervated by sympathetic nerve terminals.