The effect of selective alpha 1- and alpha 2-adrenoceptor stimulation on intraocular pressure in the conscious rabbit.

The influence of topically applied selective alpha 1-and alpha 2-adrenoceptor agonists on intraocular pressure and the diameter of the pupil was investigated in conscious rabbits. Selective stimulation of the alpha 1-subtype of receptors induced an elevation in intraocular pressure, accompanied by mydriasis, whereas stimulation of the alpha 2-subtype caused a marked and dose-dependent ocular hypotensive response, which was blocked by the selective alpha 2-adrenoceptor antagonist yohimbine. alpha 2-Agonists induced neither macroscopic ocular side effects, nor an effect on the pupil size. Possibly, the subclass of alpha 2-adrenoceptor stimulating drugs represents a group of new antiglaucomatous agents.