Pe-11, A Peptide Derived From Chromogranin B, In The Rat Eye

Abstract

Purpose: : To investigate the presence and distribution of PE-11, a peptide derived from chromogranin B, in the rat eye.

Methods: : Newborn rats were subcutaneously injected with a single dosage of 50mg/kg capsaicin under the neck fold and after three months, particular eye tissues were dissected and the concentration of PE-11 was determined by radioimmunoassay. Then the distribution pattern of PE-11 was investigated in the rat eye and rat trigeminal ganglion by immunofluorescence.

Results: : Capsaicin pretreatment led to a 88.05 % (± 7.07) and a 64.26 % (± 14.17) decrease of the levels of PE-11 in the cornea and choroid/sclera, respectively, and to a complete loss in the iris/ciliary body complex compared to controls. Sparse nerve fibers were visualized in the corneal and uveal stroma, surrounding blood vessels at the limbus, ciliary body and choroid and in association with the dilator and sphincter muscle. Furthermore, immunoreactivity was present in the corneal endothelium. Glia was labeled in the retina and optic nerve. In the rat trigeminal ganglion, PE-11-like immunoreactivity was visualized in small sized ganglion cells with a diameter of up to 30µm.

Conclusions: : These data provide evidence that PE-11 is a constituent of capsaicin-sensitive sensory neurons innervating the rat eye and the distribution pattern is typically peptidergic in the peripheral innervation but in the retina completely atypical for neuropeptides and unique.

Keywords: immunohistochemistry • neuropeptides • retina: neurochemistry