title: Nitric oxide synthase expression in the transient ischemic rat retina: neuroprotection of betaxolol.
abstract: 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.
authors.affiliation: Department of Anatomy and Neurobiology, College of Medicine, Gyeongsang National University, 92 Chilam-dong, Chinju, Kyungnam 660-751, South Korea.
authors.forename: Eun Woo
authors.initials: EW
authors.lastname: Cheon
authors.forename: Chang Hwan
authors.initials: CH
authors.lastname: Park
authors.forename: Sang Soo
authors.initials: SS
authors.lastname: Kang
authors.forename: Gyeong Jae
authors.initials: GJ
authors.lastname: Cho
authors.forename: Ji Myong
authors.initials: JM
authors.lastname: Yoo
authors.forename: Joon Kyung
authors.initials: JK
authors.lastname: Song
authors.forename: Wan Sung
authors.initials: WS
authors.lastname: Choi
mesh_terms: 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
chemical_list: D018696:Neuroprotective Agents; D019001:Nitric Oxide Synthase; D015784:Betaxolol