Reinnervation of primate ciliary muscle following ciliary ganglionectomy

Ciliary ganglionectomy and/or postganglionic ciliary neurectomy in the cynomolgus monkey was followed by supersensitivity to intramuscular (i.m.) pilocarpine and lack of response to topical eserine and to electrical stimulation of the Edinger-Westphal nucleus. Normal responsiveness to pilocarpine and eserine returned in most instances after about 6 months. An accommodative response to stimulus of the Edinger-Westphal nucleus was also present and, as in control eyes, could be blocked by hexamethonium. Collectively, these findings demonstrate that parasympathetic innervation to the ciliary muscle mediating accommodation traverses a typical peripheral autonomic synapse, almost certainly located predominantly in the ciliary ganglion; by 6 months after denervation, the ciliary muscles have reinnervated; and the parasympathetic pathway to the eye exhibits plasticity and capacity for regeneration.