Figure 5. The L-type Ca²⁺ channel and Ca²⁺ store refilling.

A, carbachol-induced Ca²⁺ transients. Nifedipine (10 μm) was introduced between the second and third Ca²⁺ transients. B, carbachol-induced Ca²⁺ transients before and after zero-Ca²⁺ superfusate. Following the zero-Ca²⁺ solution verapamil (20 μm) was added to the Ca²⁺-containing superfusate for the first five carbachol exposures, thereafter the verapamil was removed. C, caffeine-induced Ca²⁺ transients in a detrusor cell under voltage-clamp at −60 mV. Between the first and second exposures to caffeine the cell was subjected to a train of five depolarising steps (-60 to +10 mV, 500 ms duration).