P66 Hydrogen sulfide mediates an increase in intracellular calcium in HEK-293 and IMR-32 cells

Abstract

Introduction Hydrogen sulfide (H2S) is a gasotransmitter that modulates various biological functions including nociception. The mechanisms by which H2S exerts these effects are being elucidated and may involve Transient Receptor Potential (TRP) channels. TRP channels are also important in nociception, with TRPV1 and TRPA1 postulated to play a prominent role in pulmonary inflammation and airway hypersensitivity. Methods Cell suspension based flourometric calcium assays, were used to investigate the effects of NaHS (a H2S donor) on Human Embryonic Kidney-293 cells transfected with either human TRP channels or an empty plasmid, as well as on IMR-32 neuroblastoma cells. Results Application of NaHS resulted in a concentration dependent increase in fluorescence in both cell lines (EC50 TRPA1 = 34 micromolar, TRPV1 = 10 micromolar, IMR-32 = 16 micromolar), including those not transfected with TRP channels (EC50 = 9 micromolar; n = 3 for each). This rise was rapid in onset, prolonged, and persistently increased at concentrations above 10 micromolar. The responses to NaHS were not significantly attenuated using antagonists of TRPA1 or V1. Discussion and Conclusion These results suggest that H2S at physiologically relevant concentrations can increase intracellular calcium independent of the nociceptor TRP channels. This novel observation requires further investigation to elucidate the potentially new mechanism through which H2S may modulate biological processes such as nociception.