[Ocular hypotensive effects of topically applied bunazosin, an alpha 1-adrenoceptor blocker, in rabbits and cats].
Effects of topically applied bunazosin, an alpha 1-adrenoceptor blocker, on intraocular pressure (IOP) and pupillary diameter were investigated in normotensive rabbits and cats, in addition to experimentally hypertensive rabbits. Bunazosin (0.005% to 0.1%) applied to both eyes significantly lowered IOP in a concentration-dependent manner in normotensive rabbits and cats. The unilateral application of 0.1% bunazosin significantly lowered the IOP in the treated eye, whereas it caused no significant change in the contralateral eye, suggesting that the effect of bunazosin is due mainly to a direct and local action and is not systemic. Bunazosin was also effective in experimentally hypertensive models induced both by water-loading and by alpha-chymotrypsin in rabbits. There was a significant correlation between the IOP decrease caused by bunazosin and the IOP value before the application, indicating that the IOP-lowering action of bunazosin is dependent on the height of the original IOP level. Bunazosin had no influence on pupillary diameter even when 0.5% was applied to rabbits. Topically applied bunazosin may be useful as a new antiglaucoma agent.
Central Research Laboratories, Santen Pharmaceutical Company Limited, Osaka, Japan.
K
K
Nishimura
E
E
Shirasawa
M
M
Kinoshita
M
M
Hikida
Y
Y
Kuwayama
D000287:Administration, Topical; D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D002415:Cats; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D011799:Quinazolines / Q000008:administration & dosage / Q000494:pharmacology*; D011817:Rabbits
D000317:Adrenergic alpha-Antagonists; D011799:Quinazolines; C018176:bunazosin