Ocular hypotensive effects of monoamine oxidase-A inhibitors in rabbit.
The effects of monoamine oxidase-A (MAO-A) inhibitors with epinephrine on intraocular pressure in the pigmented rabbit were studied. MAO-A inhibitors were used topically with or without various concentrations of epinephrine. For the measurement of intraocular pressure, applanation pneumatonography was used and tissue MAO activities were determined by radiometric assay. After topical administration with clorgyline, MAO-A activities in the bulbar conjunctiva and the iris-ciliary body were remarkably inhibited, whereas MAO-B inhibition was minimal. Maximal reduction of intraocular pressure with 0.05% epinephrine was 3.2 mmHg. Single administration of clorgyline, amiflamine, moclobemide or CGP 11305-A caused decreases in the intraocular pressure of 2.0, 2.5, 1.8 and 2.4 mmHg, respectively. In the coadministration experiments with epinephrine, the ocular hypotensive effects of epinephrine were potentiated with clorgyline, amiflamine, moclobemide and CGP 11305-A (6.6, 4.8, 5.6 and 5.8 mmHg). On the contrary, they were not influenced by the MAO-B inhibitor deprenyl. These results indicated that MAO-A inhibitors potentiated the ocular hypotensive effects of epinephrine, and that the coadministration of a reversible MAO-A inhibitor with epinephrine might be useful for patients with glaucoma.
Maeda
I
I
Department of Ophthalmology, School of Medicine, Showa University, Tokyo, Japan.
Ueda
T
T
Koide
R
R
Inatomi
M
M
Fukado
Y
Y
Uchida
E
E
Oguchi
K
K
Yasuhara
H
H
D000818:Animals; D004357:Drug Synergism; D004837:Epinephrine / Q000494:pharmacology; D005123:Eye / Q000378:metabolism; D007429:Intraocular Pressure / Q000187:drug effects*; D008995:Monoamine Oxidase / Q000378:metabolism; D008996:Monoamine Oxidase Inhibitors / Q000494:pharmacology*; D011680:Pupil / Q000187:drug effects; D011817:Rabbits; D013997:Time Factors; D013999:Timolol / Q000494:pharmacology; D014018:Tissue Distribution
D008996:Monoamine Oxidase Inhibitors; D013999:Timolol; D008995:Monoamine Oxidase; D004837:Epinephrine