Common Pesticide Rotenone Interference with Neuronal Transmission in Hippocampus

Abstract

Rotenone is a pesticide and piscicide, wh ich causes behavioral and biochemical changes in rats that closely resemble PD sympto ms in hu mans. Rotenone is a naturally occurring ret inoid plant ext ract derived fro m the roots of certain tropical and subtropical legu me p lants and interferes with energy p roduction in the cell. Rotenone is highly lipophilic, so it can easily cross the blood brain barrier and cellular memb rane for intracellular entry.It is known that this pesticide causes superoxide release and results in decreased energy production by inhibiting electron transport chain of mitochondria fro m NADH ubiquinone reductaseand may lead to neuronal death. The object of the current research is to investigate the effect of rotenone on synaptic transmission in h ippocampus, especially on glutamatergic transmission for a b rief exposure time. For this purpose, hippocampal CA 1 pyramidal neuronal response upon low frequency stimulation of Schaffer collateral (0.1 Hz) was recorded by the patch clamp tight-seal whole cell recording technique. Different rotenone concentrations were tested on total glutamate current; it was observed that the rotenone effect on the amplitude of glutamatergic currents is dependent on its concentration. To eliminate the rotenone induced cytoplasmic effects, ATP was excluded fro m the intracellular solution in experiments. Our experimental results show that the drug acutely and dose-dependently attenuates the currents that are med iated by glutamate, v ia a direct effect on cell membrane g lutamate receptors.