Effect of O-superfamily conotoxin SO3 on synchronized spontaneous calcium spikes in cultured hippocampal networks

摘要

SO3 belongs to the O-superfamily of conotoxins and is known to have analgesic effects in experimental animals. In order to explore the mechanism of its potential pharmacological actions, the effect of SO3 on synchronized spontaneous calcium spikes was examined in cultured hippocampal networks by calcium imaging. Spontaneous oscillations of intracellular concentrations of calcium (Ca(2+)) in the form of waves and spikes are found in cultured hippocampal networks. Exposure to increasing concentrations of SO3 resulted in a progressive decrease in synchronized spontaneous calcium spikes. The higher concentrations (0.1 mumol/L and 1 mumol/L) of SO3 showed the strongest inhibition. The rank order of inhibition was 1 mumol/L > 0.1 mumol/L > 10 mumol/L > 0.01 mumol/L. This action of SO3 in reducing synchronized calcium spikes suggests a possible application for therapeutic treatment of epilepsy.