The 2-aminoethoxydiphenyl borate analog, DPB161 blocks store-operated Ca(2+) entry in acutely dissociated rat submandibular cells

Cellular Ca(2+) signals play a critical role in cell physiology and pathology. In most non-excitable cells, store-operated Ca(2+) entry (SOCE) is an important mechanism by which intracellular Ca(2+) signaling is regulated. However, few drugs can selectively modulate SOCE. 2-Aminoethoxydiphenyl borate (2APB) and its analogs (DPB162 and DPB163) have been reported to inhibit SOCE. Here, we examined the effects of another 2-APB analog, DPB161 on SOCE in acutely-isolated rat submandibular cells. Both patch-clamp recordings and Ca(2+) imaging showed that upon removal of extracellular Ca(2+) ([Ca(2+)](o)=0), rat submandibular cells were unable to maintain ACh-induced Ca(2+) oscillations, but restoration of [Ca(2+)](o) to refill Ca(2+) stores enable recovery of these Ca(2+) oscillations. However, addition of 50 μM DPB161 with [Ca(2+)](o) to extracellular solution prevented the refilling of Ca(2+) store. Fura-2 Ca(2+) imaging showed that DPB161 inhibited SOCE in a concentration-dependent manner. After depleting Ca(2+) stores by thapsigargin treatment, bath perfusion of 1 mM Ca(2+) induced [Ca(2+)](i) elevation in a manner that was prevented by DPB161. Collectively, these results show that the 2-APB analog DPB161 blocks SOCE in rat submandibular cells, suggesting that this compound can be developed as a pharmacological tool for the study of SOCE function and as a new therapeutic agent for treating SOCE-associated disorders.