title: Protective effects of betaxolol in eyes with kainic acid-induced neuronal death.
abstract: In the present study, we investigated whether betaxolol, a selective beta1-adrenoceptor antagonist, has neuroprotective effect on kainic acid (KA)-induced retinal damage. Neurotoxicities were induced in adult male rats by intravitreal injection of KA (total amount, 6 nmol). To examine the neuroprotective effects of betaxolol, rats were pretreated with betaxolol topically 60 min before KA injection to the rat eyes and twice daily for 1, 3, and 7 days after KA injection. The neuroprotective effects of betaxolol were estimated by measuring the thickness of the various retinal layers, and by counting the number of choline acetyltransferase (ChAT)- and tyrosine hydroxylase (TH)-positive cells in each retinal layer. The retina is highly vulnerable to KA-induced neuronal damage. Morphometric analysis of retinal damage in KA injected eyes, the thickness of the retinal layers decreased markedly after KA injection period of both 3 and 7 days. Furthermore, the numbers of ChAT- and TH-positive cells were significantly reduced by intravitreal injection of KA. However, when two drops of betaxolol, once before KA injection and twice daily for 7 days after KA injection, were continuously administered, the reductions in the retinal thickness and the retinal ChAT- and TH-positive cells were significantly attenuated. The present study suggests that topically applied betaxolol has neuroprotective effect on the retinal cell damage due to KA-induced neurotoxicity.
authors.affiliation: Division of Food Science, Jinju International University, 270 San Sangmun-ri Munsan-eup, Jinju, Kyungnam 660-759, South Korea.
authors.forename: Eun Woo
authors.initials: EW
authors.lastname: Cheon
authors.forename: Chang Hwan
authors.initials: CH
authors.lastname: Park
authors.forename: Yoon Sook
authors.initials: YS
authors.lastname: Kim
authors.forename: Chang Hyun
authors.initials: CH
authors.lastname: Cho
authors.forename: Young Chul
authors.initials: YC
authors.lastname: Chung
authors.forename: Jong Gil
authors.initials: JG
authors.lastname: Kwon
authors.forename: Ji Myong
authors.initials: JM
authors.lastname: Yoo
authors.forename: Wan Sung
authors.initials: WS
authors.lastname: Choi
authors.forename: Gyeong Jae
authors.initials: GJ
authors.lastname: Cho
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D015784:Betaxolol / Q000008:administration & dosage*; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000187:drug effects; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D004195:Disease Models, Animal; D004333:Drug Administration Routes; D004334:Drug Administration Schedule; D007150:Immunohistochemistry / Q000379:methods; D007608:Kainic Acid; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000008:administration & dosage*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000378:metabolism / Q000473:pathology; D012164:Retinal Diseases / Q000139:chemically induced / Q000473:pathology / Q000517:prevention & control*; D013997:Time Factors; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism
chemical_list: D018696:Neuroprotective Agents; D014446:Tyrosine 3-Monooxygenase; D002795:Choline O-Acetyltransferase; D015784:Betaxolol; D007608:Kainic Acid