IL-16 mediated changes in the intracellular levels of calcium in HMC-1 cells. (A) Untreated HMC-1 cells (trace 1), HMC-1 cells that had been previously exposed to the CD9-specific sense oligonucleotide (trace 2), and HMC-1 cells that had been previously exposed to the CD9-specific antisense oligonucleotide (trace 3) were Fluo-4 loaded and exposed to IL-16 for 1 minute (indicated by the bar), and the time-dependent rise in calcium levels [Ca²⁺]_i was measured in each instance. At the indicated time points (arrows), the treated cells were exposed to ionomycin to achieve a maximal calcium response. (B) Histogram representing differences in %F/Fmax fluorescence intensity changes of Fluo-4 in untreated and oligonucleotide-treated HMC-1 cells in the absence of extracellular calcium (mean ± SD, n = 3; ^*P < .005 [Student t test]). A scale of 0% to 100% was used, where 0% represents no change in %F/Fmax and 100% represents change in %F/Fmax due to the positive control obtained with ionomycin.