Pharmacological Dissection of the Crosstalk between Na<sub>V</sub> and Ca<sub>V</sub> Channels in GH3b6 Cells

Pharmacological Dissection of the Crosstalk between Na<sub>V</sub> and Ca<sub>V</sub> Channels in GH3b6 Cells

Thanks to the crosstalk between Na<sup>+</sup> and Ca<sup>2+</sup> channels, Na<sup>+</sup> and Ca<sup>2+</sup> homeostasis interplay in so-called excitable cells enables the generation of action potential in response to electrical stimulation. Here, w...

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Bibliographic Details
Main Authors:	Léa Réthoré, Joohee Park, Jérôme Montnach, Sébastien Nicolas, Joseph Khoury, Elodie Le Seac’h, Kamel Mabrouk, Harold De Pomyers, Hélène Tricoire-Leignel, César Mattei, Daniel Henrion, Ziad Fajloun, Michel De Waard, Claire Legendre, Christian Legros
Format:	Article
Language:	English
Published:	MDPI AG 2022-01-01
Series:	International Journal of Molecular Sciences
Subjects:	GH3b6 cells voltage-gated sodium channel L-type voltage-gated calcium channel veratridine patch-clamp Fura-2
Online Access:	https://www.mdpi.com/1422-0067/23/2/827

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Summary:	Thanks to the crosstalk between Na<sup>+</sup> and Ca<sup>2+</sup> channels, Na<sup>+</sup> and Ca<sup>2+</sup> 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<sup>+</sup> (Na<sub>V</sub>) channels by neurotoxins, such as veratridine (VTD), on intracellular Ca<sup>2+</sup> concentration ([Ca<sup>2+</sup>]<sub>i</sub>) in a model of excitable cells, the rat pituitary GH3b6 cells, in order to identify the molecular actors involved in Na<sup>+</sup>-Ca<sup>2+</sup> homeostasis crosstalk. By combining RT-qPCR, immunoblotting, immunocytochemistry, and patch-clamp techniques, we showed that GH3b6 cells predominantly express the Na<sub>V</sub>1.3 channel subtype, which likely endorses their voltage-activated Na<sup>+</sup> currents. Notably, these Na<sup>+</sup> currents were blocked by ICA-121431 and activated by the β-scorpion toxin Tf2, two selective Na<sub>V</sub>1.3 channel ligands. Using Fura-2, we showed that VTD induced a [Ca<sup>2+</sup>]<sub>i</sub> increase. This effect was suppressed by the selective Na<sub>V</sub> channel blocker tetrodotoxin, as well by the selective L-type Ca<sub>V</sub> channel (LTCC) blocker nifedipine. We also evidenced that crobenetine, a Na<sub>V</sub> channel blocker, abolished VTD-induced [Ca<sup>2+</sup>]<sub>i</sub> elevation, while it had no effects on LTCC. Altogether, our findings highlight a crosstalk between Na<sub>V</sub> and LTCC in GH3b6 cells, providing a new insight into the mode of action of neurotoxins.
ISSN:	1661-6596 1422-0067