Pancreatic polypeptide-like immunoreactive nerves in the guinea pig eye.

The indirect immunofluorescence technique with antisera either to avian pancreatic polypeptide or to bovine pancreatic polypeptide stains nerve fibers in the guinea pig eye. In all regions of the uvea, immunoreactive fibers are present around large blood vessels; an association of immunoreactive nerve fibers to melanocytes is seen. Immunoreactive nerves are found throughout the choroid, including the choriocapillaris. In the ciliary body, they are seen in individual ciliary processes. The iris dilator muscle and, to a lesser degree, its sphincter are innervated. The chamber angle of the anterior segment contains immunoreactive nerve fibers, but convincing innervation to the cornea is lacking. No retinal cells stain. With some exceptions, the distribution of peripheral nerve fibers parallels that of the adrenergic innervation. Appropriate controls are negative.