Adrenergic Receptors of the Intraocular Muscles

Introduction In vivo experimentation on cat1and rabmit2seemed to indicate that mydriasis induced by adrenergic agents is the result of activation of alpha receptors which were assumed to be located in the dilator muscle. However, experiments in vitro on isolated sphincter and dilator preparations of the cat disclosed the presence of dual adrenergic receptors in each of these muscles, with alpha receptors predominating in the dilator and beta receptors in the sphincter.5Adrenergic receptors of both types were also demonstrated in the ciliary muscle of the cat, with a predominance of beta receptors over alpha. When these studies were extended to the rabbit and monkey the findings were different from those in the cat. The results are summarized in this report. To facilitate a comparison between species, previous results obtained in the cast are included. Methods The technique of enucleation,* of dissection of muscle strips and