title: Hydrogen peroxide-induced cell death in cultured Aplysia sensory neurons.
abstract: Widespread neuronal cell death occurs during normal development and as a result of pathological conditions in the nervous system of many organisms. In this study, we investigated the cytotoxicity induced by H(2)O(2) in Aplysia mechanosensory neurons, which serve as a useful model in the study of learning and memory. Treatment with hydrogen peroxide (10(-2)-10 mM) for 3 h produced a nuclear DNA breakage in Aplysia sensory neurons, as revealed by TdT-mediated dUTP nick end labeling (TUNEL) staining, in a dose-dependent manner. Prolonged treatment (6-18 h) of Aplysia sensory neurons with 1 mM hydrogen peroxide produced dramatic morphological changes, such as neurite fragmentation, disintegration of the cell body, and a change in the resting membrane potential. This change in the resting potential was biphasic, and was initially hyperpolarized about 6 h after hydrogen peroxide treatment, but this later shifted to a depolarization some 13-18 h after treatment. Electron microscopic analysis also showed that this hydrogen peroxide-induced cell death was associated with apoptotic nuclear shrinkage, chromatin condensation, and necrotic swelling of organelles. Our results demonstrate that Aplysia sensory neurons show both apoptotic and necrotic characteristics as well as biphasic changes in resting potential during hydrogen peroxide-induced cell death.
authors.affiliation: National Research Laboratory of Neurobiology, Institute of Molecular Biology and Genetics, School of Biological Sciences, College of Natural Sciences, Seoul National University, San 56-1 Silim-dong Kwanak-gu, Seoul 151-742, South Korea.
authors.forename: Chae Seok
authors.initials: CS
authors.lastname: Lim
authors.forename: Jong Cheol
authors.initials: JC
authors.lastname: Lee
authors.forename: Su Dong
authors.initials: SD
authors.lastname: Kim
authors.forename: Deok Jin
authors.initials: DJ
authors.lastname: Chang
authors.forename: Bong Kiun
authors.initials: BK
authors.lastname: Kaang
mesh_terms: D000818:Animals; D001048:Aplysia; D018929:Cell Culture Techniques; D016923:Cell Death / Q000187:drug effects*; D004594:Electrophysiology; D006861:Hydrogen Peroxide / Q000009:adverse effects*; D020287:In Situ Nick-End Labeling; D008854:Microscopy, Electron; D009475:Neurons, Afferent / Q000187:drug effects*; D016877:Oxidants / Q000009:adverse effects*; D018384:Oxidative Stress / Q000187:drug effects
chemical_list: D016877:Oxidants; D006861:Hydrogen Peroxide