Amelioration of endothelin-1-induced optic nerve head ischemia by topical bunazosin.
OBJECTIVE
To investigate the effects of bunazosin hydrochloride, an alpha1-adrenergic blocker, on the impairment of optic nerve head (ONH) blood flow and depression of visual function induced by repeated intravitreal injections of endothelin-1 (ET-1) in rabbits.


METHODS
We injected ET-1 (20 pmol) into the right posterior vitreous of rabbits twice a week for 4 weeks, and the observation period was set at 8 weeks (starting the first injection). The animals that received ET01 were divided into two groups: twice a day for 8 weeks, o ne group received topical 0.01% bunazosin, while the second received the vehicle for bunazosin. The ONH blood flow was monitored using the laser speckle method, and visual function was assessed by examining visually evoked potentials (VEPs). Changes in the ONH cup/disk area and in the number of cells in the retinal ganglion cell layer (CCL) were also determined.


RESULTS
Repeated injections of ET-1 decreased the ONH blood flow, prolonged the VEP implicit time, enlarged the optic cup, and decreased the number of GCL cells. Topical bunazosin significantly decreased these impairments.


CONCLUSIONS
These results indicate that in rabbits, topical bunazosin suppresses the changes in ONH circulation and function induced by intravitreal ET-1.
Goto
Wakana
W
Department of Ophthalmology, Osaka Medical College, Takatsuki, Osaka, Japan.
Oku
Hidehiro
H
Okuno
Takashi
T
Sugiyama
Tetsuya
T
Ikeda
Tsunehiko
T
D000287:Administration, Topical; D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage*; D000818:Animals; D001794:Blood Pressure; D019332:Endothelin-1 / Q000494:pharmacology*; D005074:Evoked Potentials, Visual / Q000187:drug effects; D007267:Injections; D007429:Intraocular Pressure; D007511:Ischemia / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D009898:Optic Disk / Q000098:blood supply* / Q000473:pathology; D011799:Quinazolines / Q000008:administration & dosage*; D011817:Rabbits; D012039:Regional Blood Flow / Q000187:drug effects; D012160:Retina / Q000187:drug effects / Q000473:pathology; D014822:Vitreous Body
D000317:Adrenergic alpha-Antagonists; D019332:Endothelin-1; D011799:Quinazolines; C018176:bunazosin