Figure 5.

The virtual screening hit Ned-19 reveals that glucose-induced Ca²⁺ increases require NAADP signaling. (a) Ned-19 inhibits glucose-induced Ca²⁺ oscillations. (b) Ned-20 does not affect glucose-induced Ca²⁺ increases. (c,d) Ned-19 reduces glucose-induced Ca²⁺ increases in a concentration-dependent manner. Islets were pre-incubated with the indicated concentration of Ned-19 for 30 min before the addition of 15 mM glucose. “Con” is the control. (e) Ned-19 does not affect the activation of voltage-gated Ca²⁺ channels. Cells were incubated in glucose (10 mM) and diazoxide (100 μM) and then depolarized with KCl (45 mM) in the presence and absence of Ned-19 (100 μM). (f) Ned-19 does not interfere with mitochondrial production of NAD(P)H. All cells were maintained in 3 mM glucose unless otherwise indicated.