Lavandula angustifolia Mill. inhibits high glucose and nicotine-induced Ca2+influx in microglia and neuron-like cells via two distinct mechanisms

Smoking remains a significant health problem in patients with type 2 diabetes mellitus. This study compared intracellular Ca 2 + ([Ca 2 + ] i ) in microglia, neurons, and astrocytes in the presence of high glucose (HG) and nicotine and evaluated the effects of Lavandula angustifolia Mill. essential oil (LEO) on this process. [Ca 2 + ] i concentrations were measured by monitoring the fluorescence of Fura-2 acetoxymethyl ester. Treatment with HG and nicotine significantly increased [Ca 2 + ] i in both microglia and neurons through Ca 2 + influx from extracellular sources. This increased Ca 2 + influx in microglia, however, was significantly reduced by LEO, an effect partially inhibited by the Na + /Ca 2 + exchanger (NCX) inhibitor Ni 2 + . Ca 2 + influx in neuron-like cells pretreated with HG plus nicotine was also significantly decreased by LEO, an effect partially inhibited by the L-type Ca 2 + channel blocker nifedipine and the T-type Ca 2 + channel blocker mibefradil. LEO or a two-fold increase in the applied number of astrocytes attenuated Ca 2 + influx caused by high glucose and nicotine in the mixed cells of the microglia, neuron-like cells and astrocytes. These findings suggest that LEO can regulate HG and nicotineinduced Ca 2 + influx into microglia and neurons through two distinct mechanisms.