Fig. 4. The presence of Cav1 causes a sustained Ca²⁺ response. Change in intracellular Ca²⁺ in 1-ml suspensions of 10⁶ FRTcav⁺ or FRTcav^– cells transfected with either empty vector, PLCβ1 or PLCβ2, and loaded with the Ca²⁺-sensitive dye FURA-2AM upon addition of 1 µM acetylcholine (see Materials and Methods). n=6 of triplicate sets of samples. Black arrows indicate time of stimulus addition.