PAR-2 receptor functionality in L6 myoblasts. A) Levels of phospho-ERK1/2 and total ERK1/2 by western blot following stimulation with tryptase, tryptase pre-incubated with its inhibitor APC-366 or with COX-2 inhibitor NS-398. GAPDH served as loading control. B) Quantification of the level of phospho-ERK1/2. Each data point represents the mean of at least 4 separate experiments (mean ± s.e.m). * Significantly different from control (CTRL), P < 0.05.