Nisoldipine (BAY-k 5552) is a dihydropyridine calcium channel antagonist that acts as a potent arterial vasodilator and antihypertensive agent.

Cav 1.2, L-type:10 nM

In patients with Timothy syndrome, Nisoldipine (IC50=267 nM) induces vasodilation and lowers blood pressure by inhibiting the influx of calcium ions through L-type calcium channels, thereby decreasing the contractility of arterial smooth muscle and subsequent vasoconstriction.

In guinea pig ventricular myocytes, Nisoldipine acts on delayed rectifier K+ channels, inhibiting the rapid-activating component (IKr) with an IC50 of 23 μM, and the slow-activating component (IKs) with an IC50 of 40 μM.

Binding experiments of electrophysiology: CHO cells expressing the subunit of the voltage-dependent L-type Ca2+ channel are cultrured in medium without serum in the presence of different concentrations of Nisoldipine. Then Ca2+ channel current elicited from a holding potential of -100 mV or -50 mV is recorded at room temperature with the whole-cell configuration of the patch-clamp method using the List EPC-7 patch-clamp amplifer and pClamp software. The concentration of competitor inhibiting 50% of the specific binding represents IC50.

The myocytes are bathed in normal Tyrode's solution, held at -80 mV, and depolarised after 200-ms prepulses (-40mV) to more positive potentials for 500 ms at 0.1 Hz, tail currents are recorded on repolarisations to -40mV. The myocytes are exposed to 10-100 mM Nisoldipine for 8-10 minutes. Then the whole-cell membrane currents are recorded using an EPC-7 amplifier.(Only for Reference)