The role of the autonomic nervous system in extraocular muscle function.

The purpose of this study was to determine the possible role of the autonomic nervous system in the function of mammalian extraocular muscle. Experiments were carried out on the cat anesthetized with pentobarbital. Stimulation of the cervical sympathetic nerve and the injection of epinephrine increased the tension of the superior rectus muscle. These responses were unaffected by sympathetic ^-receptor blocking agents, potentiated by cocaine, and antagonized by sympathetic a-receptor blocking agents. Similar results were observed with the nictitating membrane. The superior rectus muscle and nictitating membrane differed in that atropine blocked the response of the nictitating membrane to epinephrine, but not that of the superior rectus muscle. The implications of these remits are discussed.