In vitro activity: Nifedipine causes a significant concentration-dependent increase in eNOS protein expression by cultured human coronary artery endothelial cells. Nifedipine antagonizes L-type Ca+ channels found throughout the cardiovascular system, but also blocks Kv channels, which are members of the same supergene family. Nifedipine dose-dependently decreases the values of [(3)H]-thymidine incorporation and total cellular protein content as well as the levels of phosphorylated extracellular signal-regulated protein kinase (ERK) 1/2, mitogen-activated protein kinase kinase (MEK) 1/2, and even the phosphorylation of Pyk2, in vascular smooth muscle cells (VSMC). Nifedipine suppresses the levels of proliferative cell nuclear antigen (PCNA) dose-dependently in both VSMC and balloon-injured thoracic aortae in VSMC.

Cell Assay: Cell viability is assessed using an MTT assay. Briefly, a total of 25 μL MTT (1 g/L in PBS) is added to each well before incubation is conducted at 37°C for 4 h. The assay is stopped by the addition of a 100 μL lysis buffer (20% SDS in 50% N’Ndimethylformamide, pH 4.7). Optical density (OD) is measured at the 570 nm wavelength by the use of an ELX-800 microplate assay reader and the results are expressed as a percentage of the absorbance measured in the control cells.