Involvement of Src kinase in T-type calcium channel-dependent neuronal differentiation of NG108-15 cells by hydrogen sulfide.

Hydrogen sulfide (H(2)S), a gasotransmitter, induces neuronal differentiation characterized by neuritogenesis and functional up-regulation of high voltage-activated Ca(2+) channels, via activation of T-type Ca(2+) channels in NG108-15 cells. We thus analyzed signaling mechanisms for the H(2)S-evoked neuronal differentiation. NaHS, a donor for H(2)S, facilitated T-type Ca(2+) channel-dependent membrane currents, an effect blocked by ascorbic acid that selectively inhibits Ca(v)3.2 among three T-type channel isoforms. NaHS, applied once at a high concentration (13.5 mM) or repetitively at a relatively low concentration (1.5 mM), as well as ionomycin, a Ca(2+) ionophore, evoked neuritogenesis. The neuritogenesis induced by NaHS, but not by ionomycin, was abolished by mibefradil, a T-type Ca(2+) channel blocker. PP2, a Src kinase inhibitor, completely suppressed the neuritogenesis caused by NaHS or ionomycin, while it only partially blocked neuritogenesis caused by dibutyryl cAMP, a differentiation inducer. NaHS, but not dibutyryl cAMP, actually caused phosphorylation of Src, an effect blocked by 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid acetoxymethyl, an intracellular Ca(2+) chelator, mibefradil or ascorbic acid. The up-regulation of high voltage-activated currents in the cells treated with NaHS was also inhibited by PP2. Together, our data reveal that Src kinase participates in the T-type Ca(2+) channel-dependent neuronal differentiation caused by NaHS/H(2)S in NG108-15 cells.