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Figure 1. Intracellular Ca2+- and phosphoinositol-3-kinase (PI3K)-dependency of CXCL2/3-induced opioid peptide release from rat PMN. A) Rat PMN were stimulated with the indicated concentrations of CXCL2/3 and CXCL12 for 7 min. Met-enkephalin (ENK, left) and ß-endorphin (END, right) release was measured in the supernatant by RIA (n=6–19). B) CXCL2/3 (1000 nM, cross-hatched bars in all experiments)-induced opioid peptide release was analyzed in the presence (open bars) and absence (gray bars) of extracellular Ca2+ (-[Ca2+]e, n=9). CXCL2/3-induced opioid peptide release was measured after preincubation of rat PMN (for 10 min) with the intracellular Ca2+ chelator BAPTA/AM (C), (100 µM, n=5–7) or the PI3K-inhibitor wortmannin (D) (100 nM, n=6–9, respectively). *P < 0.05 significant difference compared to respective controls (all one-way repeated-measures ANOVA, Student-Newman-Keuls method). Data are expressed as means ± SEM.
