title: Endogenous and exogenous hydrogen sulfide facilitates T-type calcium channel currents in Cav3.2-expressing HEK293 cells.
abstract: 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. NaHS at 1.5mM did not affect T-currents in Cav3.2-HEK293 cells, but enhanced T-currents in NG108-15 cells. In the presence of PPG, NaHS at 1.5mM, but not 0.1-0.3mM, increased T-currents in Cav3.2-HEK293 cells. Similarly, Na2S, another H2S donor, at 0.1-0.3mM significantly increased T-currents in the presence, but not absence, of PPG in Cav3.2-HEK293 cells. Expression of CSE was detected at protein and mRNA levels in HEK293 cells. Intraplantar administration of Na2S, like NaHS, caused mechanical hyperalgesia, an effect blocked by NNC 55-0396, a T-channel inhibitor. 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.
authors: Division of Pharmacology and Pathophysiology, Kinki University School of Pharmacy, Higashi-Osaka 577-8502, Japan.
authors: Fumiko
authors: F
authors: Sekiguchi
authors: Division of Pharmacology and Pathophysiology, Kinki University School of Pharmacy, Higashi-Osaka 577-8502, Japan.
authors: Yosuke
authors: Y
authors: Miyamoto
authors: Division of Pharmacology and Pathophysiology, Kinki University School of Pharmacy, Higashi-Osaka 577-8502, Japan.
authors: Daiki
authors: D
authors: Kanaoka
authors: Division of Pharmacology and Pathophysiology, Kinki University School of Pharmacy, Higashi-Osaka 577-8502, Japan.
authors: Hiroki
authors: H
authors: Ide
authors: Department of Life Science, Kinki University School of Science and Engineering, Higashi-Osaka 577-8502, Japan.
authors: Shigeru
authors: S
authors: Yoshida
authors: Department of Physiological Science and Molecular Biology, Fukuoka Dental College, Fukuoka 814-0193, Japan.
authors: Tsuyako
authors: T
authors: Ohkubo
authors: Division of Pharmacology and Pathophysiology, Kinki University School of Pharmacy, Higashi-Osaka 577-8502, Japan. Electronic address: kawabata@phar.kindai.ac.jp.
authors: Atsufumi
authors: A
authors: Kawabata
mesh_terms: D000480:Alkynes / Q000494:pharmacology; D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D020747:Calcium Channels, T-Type / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D045744:Cell Line, Tumor; D003542:Cystathionine gamma-Lyase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D057809:HEK293 Cells; D006801:Humans; D006862:Hydrogen Sulfide / Q000378:metabolism* / Q000494:pharmacology*; D008297:Male; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology; D018408:Patch-Clamp Techniques; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013440:Sulfides / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology
chemical_list: D000480:Alkynes; C479952:CACNA1H protein, human; D020747:Calcium Channels, T-Type; D013440:Sulfides; C009055:propargylglycine; D003542:Cystathionine gamma-Lyase; C025451:sodium bisulfide; D002118:Calcium; D005998:Glycine; C033479:sodium sulfide; D006862:Hydrogen Sulfide
keywords: Ca(v)3.2; Cystathionine-γ-lyase; HEK293 cells; Hydrogen sulfide; T-type calcium channel