Nitric oxide synthase expression in the transient ischemic rat retina: neuroprotection of betaxolol.
Betaxolol is a beta-adrenergic blocker but its neuroprotective action is generally thought to be due to its calcium channel blocking properties. In this study, we investigated neuronal cell damage and changes in the expression of neuronal nitric oxide synthase (nNOS) immunoreactivity in the ischemic retina and its relationship to the neuroprotection of betaxolol treatment after ischemic injury. Using the retina after ischemia, the expression of nNOS was studied by immunocytochemistry. In control retinas, two types of amacrine cells and a class of displaced amacrine cells were nNOS-labeled. After ischemia/reperfusion, the number of nNOS immunoreactive cells increased in both the ganglion cell layer and the inner nuclear layer compared to the control retinas. However, when experiments were carried out on animals that had been treated with betaxolol twice daily after ischemia/reperfusion, the number of nNOS immunoreactive cells decreased compared to the untreated ischemic retinas. These results suggest that an increase in nNOS expression could be associated with the degenerative changes in the ischemic retina, and that betaxolol treatment appears to play a role in protecting retinal tissue from ischemic damage.
Cheon
Eun Woo
EW
Department of Anatomy and Neurobiology, College of Medicine, Gyeongsang National University, 92 Chilam-dong, Chinju, Kyungnam 660-751, South Korea.
Park
Chang Hwan
CH
Kang
Sang Soo
SS
Cho
Gyeong Jae
GJ
Yoo
Ji Myong
JM
Song
Joon Kyung
JK
Choi
Wan Sung
WS
D025042:Amacrine Cells / Q000187:drug effects / Q000201:enzymology; D000818:Animals; D015784:Betaxolol / Q000494:pharmacology*; D002545:Brain Ischemia / Q000201:enzymology; D007150:Immunohistochemistry; D007429:Intraocular Pressure / Q000502:physiology; D008297:Male; D018696:Neuroprotective Agents / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000201:enzymology*; D012160:Retina / Q000187:drug effects* / Q000201:enzymology / Q000293:injuries / Q000473:pathology; D012161:Retinal Artery / Q000473:pathology
D018696:Neuroprotective Agents; D019001:Nitric Oxide Synthase; D015784:Betaxolol