M-7 lowers rabbit intraocular pressure.

Changes in intraocular pressure (IOP) and pupil diameter were studied in albino rabbits following topical administration of TL-99, M-7 (N,N-dimethyl analogues of 2-aminotetralin), DiPr-5,6-ADTN, DiPr-6,7-ADTN (dipropyl analogues of aminotetralin) and DPDA (N,N-di-n-propyl-dopamine), known as mixed alpha-adrenoceptor/dopamine receptor agonists with variable alpha 1/alpha 2-adrenoceptor/selectivity. The potencies of those compounds to decrease IOP were compared with each other. We found that M-7 has the most potent IOP-lowering properties, caused minimal ocular discomfort and is of interest as a potential antiglaucoma agent. The ocular hypotension was completely inhibited by rauwolscine and slightly antagonized by various other blocking agents. The results strongly suggest that the IOP-lowering effect of M-7 is mediated by the stimulation of alpha 2-adrenoceptors.