title: Visually evoked cortical potentials obtained using checker patterns can detect ethambutol-induced visual toxicity in albino rats.
abstract: We determined whether visually evoked cortical potentials obtained using checker patterns (P-VECPs) and albino rats would reveal visual damage induced by ethambutol (EB). Findings were compared in cases of detection of visual damage between by P-VECPs and by flash visually evoked cortical potentials (F-VECPs). Twelve adult albino male Crj:CD(SD)IGS rats were grouped into four, three per group: control, 250PS, 500PS, and 500SC groups. In the 250PS and 500PS groups, rats were administered EB orally for the first 2 weeks and then subcutaneously for the second 2 weeks to 250 and 500 mg/kg, respectively. In the 500SC group, rats were given 500 mg/kg of EB subcutaneously for 4 weeks. Rats in the control group were given the vehicle orally for the first 2 weeks and then subcutaneouly for the second 2 weeks. P-VECPs and F-VECPs were carried out prior to initiation of drug administration and at the 1st, 2nd, 3rd, and 4th weeks of the administration. Prolongation of P1 latency in the P-VECPs was evident in both the 500PS and the 500SC groups at the 4th week, while no marked changes were observed in the F-VECPs. Thus, P-VECPs in albino rats can detect visual damage induced by EB even when F-VECPs cannot do so. These studies suggest that P-VECPs are useful for evaluating the visual toxicity of drugs.
authors.affiliation: Toxicology Laboratory, Medicinal Laboratories, Taisho Pharmaceutical Co., Ltd., 403 Yoshino-cho 1, Saitama-shi, Japan. shoji.sasaki@po.rd.taisho.co.jp
authors.forename: Shoji
authors.initials: S
authors.lastname: Sasaki
authors.forename: Kumiko
authors.initials: K
authors.lastname: Yagi
authors.forename: Isamu
authors.initials: I
authors.lastname: Nakamura
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Iwaki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Kimura
mesh_terms: D000818:Animals; D000995:Antitubercular Agents / Q000633:toxicity*; D004566:Electrodes; D004977:Ethambutol / Q000633:toxicity*; D005074:Evoked Potentials, Visual / Q000187:drug effects / Q000502:physiology*; D008297:Male; D010775:Photic Stimulation; D051381:Rats; D011919:Rats, Inbred Strains; D018675:Toxicity Tests / Q000379:methods*; D014785:Vision, Ocular / Q000187:drug effects* / Q000502:physiology; D014793:Visual Cortex / Q000502:physiology*; D014796:Visual Perception / Q000187:drug effects / Q000502:physiology
chemical_list: D000995:Antitubercular Agents; D004977:Ethambutol