(±)-Felodipine-d5 is intended for use as an internal standard for the quantification of (±)-felodipine by GC- or LC-MS. (±)-Felodipine is an inhibitor of L-type calcium channels. It induces relaxation of precontracted isolated porcine coronary artery segments (EC50 = 0.15 nM), which highly express L-type calcium channels. (±)-Felodipine is selective for L-type calcium channels over N-, R-, and P/Q-type channels at 10 μM, as well as the T-type Cav3.2 channel (IC50 = 6.8 μM). (±)-Felodipine preferentially inhibits L-type calcium channels in isolated rat portal vein over rat left ventricle (IC50s = 33.9 and 3,981 nM, respectively). It decreases mean arterial blood pressure and total peripheral resistance in a rabbit model of hypertension induced by renal artery ligation when administered intravenously at doses of 30 and 100 nmol/kg.
