Localization of substance P-like immunoreactivity in the anterior eye segment of squirrels: an immunohistochemical analysis.

Localization of substance P (SP)-like immunoreactivity in the anterior eye segment of the squirrel was examined immunohistochemically. The present study demonstrates a dense network of SP-positive fibers in the ciliary body, particularly in the muscle layers, and several SP-positive fibers in the iris, in addition to scattered SP-positive fibers in the cornea. These facts strongly suggest that SP has an important role in the physiologic functions of the anterior eye segment.