A comparison of the effects of nifedipine, verapamil, and low-molecular-weight heparin on SLIGRL-NH₂-induced calcium influx through proteinase-activated receptor 2 activation.

BACKGROUND

Proteinase-activated receptor 2 (PAR2) may be implicated in skin disorders. Intracellular calcium mobilization is a key step in PAR2-induced signaling.

AIMS: In this study, we investigated the effects of nifedipine, verapamil, and low-molecular-weight heparin (LMWH) on SLIGRL-NH₂-induced PAR2-mediated calcium mobilization within cells.

METHODS

The intracellular calcium concentration was measured with fluo-8, a fluorescence indicator for free Ca(2+).

RESULTS

Our results showed that SLIGRL-NH₂ induced a dose-dependent calcium influx. This calcium influx was completely blocked in HaCaT cells and significantly blocked by LMWH in HEK293/PAR2 cells. However, both nifedipine and verapamil failed to inhibit the SLIGRL-NH₂-induced calcium influx in either cell line.

CONCLUSION

These results indicate that the PAR2 activation-induced calcium mobilization was mediated by intracellular calcium stores but not by extracellular calcium present in the media.