Abstract
Effects of irsogladine on ionomycin-induced decrease in intercellular communication and increase in intracellular concentration of Ca2+ ([Ca2+]i) were investigated in cultured rabbit gastric epithelial cells. Ionomycin (10-7-10-6 M) transiently and concentration-dependently inhibited intercellular communication concomitantly with the elevation of [Ca2+]i in the presence and absence of extracellular Ca2+. Irsogladine (10-5M), which has been shown to facilitate intercellular communication, suppressed the ionomycin-induced elevation of [Ca2+]i and decrease in intercellular communication. The suppression of the ionomycin effects by irsogladine was independent of extracellular Ca2+. TMB-8 [8-(diethylamino)octyl-3, 4, 5-trimethoxy-benzoate hydrochloride] (10-6M) also suppressed the ionomycin-induced elevation of [Ca2+]i and decrease in intercellular communication. These results indicate that the ionomycin-induced decrease in intercellular communication may be due to Ca2+ mobilization from intracellular stores. Inhibitory effects of irsogladine and TMB-8 on the ionomycin-induced decrease in intercellular communication may be produced by suppressing Ca2+ mobilization.
