Biochemical and biophysical research communications
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Biochem. Biophys. Res. Commun. · Feb 2014
Endogenous and exogenous hydrogen sulfide facilitates T-type calcium channel currents in Cav3.2-expressing HEK293 cells.
Hydrogen sulfide (H2S), a gasotransmitter, is formed from l-cysteine by multiple enzymes including cystathionine-γ-lyase (CSE). We have shown that an H2S donor, NaHS, causes hyperalgesia in rodents, an effect inhibited by knockdown of Cav3.2 T-type Ca(2+) channels (T-channels), and that NaHS facilitates T-channel-dependent currents (T-currents) in NG108-15 cells that naturally express Cav3.2. In the present study, we asked if endogenous and exogenous H2S participates in regulation of the channel functions in Cav3.2-transfected HEK293 (Cav3.2-HEK293) cells. dl-Propargylglycine (PPG), a CSE inhibitor, significantly decreased T-currents in Cav3.2-HEK293 cells, but not in NG108-15 cells. ⋯ The in vivo potency of Na2S was higher than NaHS. These results suggest that the function of Cav3.2 T-channels is tonically enhanced by endogenous H2S synthesized by CSE in Cav3.2-HEK293 cells, and that exogenous H2S is capable of enhancing Cav3.2 function when endogenous H2S production by CSE is inhibited. In addition, Na2S is considered a more potent H2S donor than NaHS in vitro as well as in vivo.