Effects of aminotetralins on intraocular pressure and pupillary function in rabbits

Aminotetralin compounds, A-6, 7-DTN and TL-99, produced bisphasic changes in intraocular pressure (IOP) and pupillary dilatation in rabbits. The rise in IOP appeared to result from an action on extraocular muscles because this effect was not produced by either compound in rabbits with transected extraocular muscles. The ocular hypotensive action of A-6, 7-DTN and TL-99 was markedly attenuated in sympathectomized rabbits indicating that this action resulted from suppression of sympathetic neuronal activity. Inhibition of ocular hypertension induced by waterloading by both compounds and suppression of the IOP recovery rate by A-6, 7-DTN suggested that the latter compound lowered IOP, in part, by inhibiting aqueous humor formation. The ocular hypotensive action of A-6, 7-DTN was antagonized by pretreatment with sulpiride, but not by yohimbine, indicating that dopamine receptors are involved in the response. These studies demonstrated that dopamine agonists can lower IOP and suggest that these types of drugs might prove useful in the therapy of open-angle glaucoma.