Aim: To clarify the mechanisms of interaction between SiO2 nanoparticles (NPs) and the plasma membrane of GT1-7 neuroendocrine cells, with focus on the activation of calcium-permeable channels, responsible for the long lasting calcium influx and modulation of the electrical activity in these cells.
Materials & methods: Nontoxic doses of SiO2 NPs were administered to the cells. Calcium imaging and patch clamp techniques were combined with a pharmacological approach.
Results: TRPV4, Cx and Panx-like channels are the major components of the NP-induced inward currents. Preincubation with the antioxidant N-acetyl-L-cysteine strongly reduced the [Ca2+]i increase.
Conclusion: These findings suggest that SiO2 NPs directly activate a complex set of calcium-permeable channels, possibly by catalyzing free radical production.
Keywords: Cx channels; Panx channels; TRPV4 channels; calcium; free radicals; neuronal cells; patch clamp; silica nanoparticles; single channel.