Common Pesticide Rotenone Interference with Neuronal Transmission in Hippocampus

Rotenone is a pesticide and piscicide, which causes behavioral and biochemical changes in rats that closely resemble PD symptoms in humans. Rotenone is a naturally occurring retinoid plant extract derived from the roots of certain tropical and subtropical legume plants and interferes with energy production in the cell. Rotenone is highly lipophilic, so it can easily cross the blood brain barrier and cellular membrane 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 from 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 hippocampus, especially on glutamatergic transmission for a brief exposure time. For this purpose, hippocampal CA1 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 from the intracellular solution in experiments. Our experimental results show that the drug acutely and dose-dependently attenuates the currents that are mediated by glutamate, via a direct effect on cell membrane glutamate receptors.