2022 - Pharmacological Dissection of the Crosstalk between NaV and CaV Channels in GH3b6 Cells
SyncroPatch 384PE (a predecessor model of the SyncroPatch 384 instrument) Publication in International Journal of Molecular Sciences (2022)
Authors:
Réthoré L., Park J., Montnach J., Nicolas S., Khoury J., Le Seac’h E., Mabrouk K., De Pomyers H., Tricoire-Leignel H., Mattei C., Henrion D., Fajloun Z., De Waard M., Legendre C., Legros C.
Journal:
International Journal of Molecular Sciences (2022) doi:10.3390/ijms23020827
Abstract:
Thanks to the crosstalk between Na+ and Ca2+ channels, Na+ and Ca2+ homeostasis interplay in so-called excitable cells enables the generation of action potential in response to electrical stimulation. Here, we investigated the impact of persistent activation of voltage-gated Na+ (NaV) channels by neurotoxins, such as veratridine (VTD), on intracellular Ca2+ concentration ([Ca2+]i) in a model of excitable cells, the rat pituitary GH3b6 cells, in order to identify the molecular actors involved in Na+-Ca2+ homeostasis crosstalk. By combining RT-qPCR, immunoblotting, immunocytochemistry, and patch-clamp techniques, we showed that GH3b6 cells predominantly express the NaV1.3 channel subtype, which likely endorses their voltage-activated Na+ currents. Notably, these Na+ currents were blocked by ICA-121431 and activated by the β-scorpion toxin Tf2, two selective NaV1.3 channel ligands. Using Fura-2, we showed that VTD induced a [Ca2+]i increase. This effect was suppressed by the selective NaV channel blocker tetrodotoxin, as well by the selective L-type CaV channel (LTCC) blocker nifedipine. We also evidenced that crobenetine, a NaV channel blocker, abolished VTD-induced [Ca2+]i elevation, while it had no effects on LTCC. Altogether, our findings highlight a crosstalk between NaV and LTCC in GH3b6 cells, providing a new insight into the mode of action of neurotoxins.
