Kainic acid induces selective mitochondrial oxidative phosphorylation enzyme dysfunction in cerebellar granule neurons: protective effects of melatonin and GSH ethyl ester.

Abstract

SPECIFIC AIMSIn this study, we addressed the hypothesis that the potent central nervous system (CNS) excitotoxin kainic acid (KA) causes neuronal death via production of reactive oxygen species (ROS), which leads to mitochondrial dysfunction. The effects of KA on cellular viability, levels of intracellular ROS and mitochondrial oxidative phosphorylation (OXPHOS) enzyme activities have been investigated in vitro on rat cerebellar granule neurons, together with the neuroprotective potential of melatonin and GSH ethyl ester.PRINCIPAL FINDINGS1. KA reduces cerebellar granule neuron survivalTreatment of cerebellar granule neurons at 14 days in vitro with KA for 30–60 min resulted in a concentration-dependent reduction in survival after 24 h, as quantified using the viability dye 3-(4,5-dimethylthiazol-2-yl)-2,5-tetrazolium bromide. Maximal cell death (46.0±4.0% of control) was achieved with a 30 min exposure to 0.5 mM KA; the latter conditions were chosen for all subsequent experiments.2. KA impairs mitochondr...