Fig. 2. Effect of inhibitors of ADPR cyclase on endothelin-1 (ET-1)-stimulated increases in [Ca²⁺]_i in vascular smooth muscle (VSM). (A) Representative tracing of the [Ca²⁺]_i response to ET-1 in the presence and absence of nicotinamide. (B) Representative tracing of the response to ET-1 in the presence and absence of Zn²⁺. (C) Summary data of the effects of nicotinamide (N=15) and Zn²⁺ (N=11) on the ET-1-induced peak elevation of [Ca²⁺]_i. ^*P<0.01 for both inhibitors vs ET-1 alone.