Effect of topical and intracameral methysergide on calcitonin gene-related peptide-induced irritative changes in the rabbit eye.

Calcitonin gene-related peptide (CGRP) is a neuropeptide localized in the ocular sensory nerves. It is responsible for most of the irritative changes in the rabbit eye in neurogenic inflammation, namely vasodilation in the anterior uvea, breakdown of the blood-aqueous barrier and increase in the intraocular pressure. In the present study, intracameral methysergide inhibited the CGRP-induced irritative changes in the rabbit eye. Provided that sufficient concentration of methysergide could be reached in the anterior chamber after topical application, it might be possible to use locally administered methysergide to limit different pathophysiological conditions in the eye in which CGRP is involved.