Voltage dependent L-type Ca2+ channels play an important role Ca2+ influx. L-type calcium currents typically require a strong depolarization for activation and are long-lasting.
The common pharmacological profile of L-type channels is determined by the (A)1 subunit, which forms the Ca2+ selective pore, and is encoded by one of the CaV1 ((A) 1S) channel genes. Cav1.2 (CACNA1C) in humans is widely expressed in cardiac myocytes, smooth muscle myocytes, endocrine cells, neuronal cell bodies and proximal dendrites.
Flavoxate hydrochloride is widely used for the treatment of urinary frequency. Flavoxate increases urinary bladder capacity primarily by suppressing the micturition reflex through modulation of the central nervous system. However, in addition to its activity in the CNS, it possesses direct inhibitory effects on the detrusor muscle. Flavoxate causes a detrusor relaxation through inhibition of L-type Ca+2 (CaV1.2) channels in human urinary bladder detrusor smooth muscle, in a concentration-dependent manner.