Alteration in the histochemical presence of tyrosine hydroxylase and CGRP-immunoreactivities in the eye following chronic sympathetic or sensory denervation.

Changes in the content of calcitonin gene-related polypeptide (CGRP) and tyrosine hydroxylase (TH) immunoreactivities in the anterior segment of the rat eye were assessed histochemically in animals subjected to sympathetic ganglionectomy or to chronic sensory denervation induced by neonatal capsaicin treatment. In the sympathectomised eyes there was a marked depletion of TH and increase in CGRP immunoreactivity while in tissue subjected to sensory denervation the reverse was found, raised presence of TH and absence of CGRP-immunostaining. The results suggest important neurotrophic influences by the host tissue or a trophic interaction of one nerve set on another.