THE INFLUENCE OF THE SYMPATHETIC NERVOUS SYSTEM ON THE ACTION OF DRUGS ON THE LENS

¹ Department of Pharmacology, St. Mary's Hospital Medical School, London, England

Morphine and related drugs produce reversible opacities in the lens of mice within 15 min of injection. This effect can be prevented by drugs which abolish sympathetic nerve activity in the eye and produce ptosis. These include phentolamine, phenoxybenzamine, guanethidine and reserpine. Antagonism by reserpine is evident within 15 min of its injection and lasts 24 hr. The lenticular effect is also prevented by cervical sympathectomy. The opacity results from prolonged lid retraction due to central stimulation of the sympathetic nervous system by analgesic drugs. The changes produced by lid retraction on the tonicity of the aqueous humor are discussed. The lens opacity produced by chlorpromazine and imipramine is not due to lid retraction but to an effect which results from the hypothermia they cause in mice.