Responsiveness of the rabbit eye to adrenergic and cholinergic agonists after treatment with 6-hydroxydopamine or alpha-methyl-para-tyrosine: Part I--Pupillary changes.

The responses of rabbit pupils to graded doses of both adrenergic and cholinergic drugs after chemical sympathectomy with 6-hydroxydopamine have been examined. For comparison, similar data were obtained in rabbits treated chronically with the norepinephrine synthesis inhibitor, alpha-methyl-para-tyrosine. While quantitative differences were apparent, the effects of these 2 treatments were qualitatively similar. In both cases, a marked reduction in the responsiveness of the iris to cholinergic agonists accompanied the development of supersensitivity to adrenergic amines.