6533b872fe1ef96bd12d3129

RESEARCH PRODUCT

Voltage-Dependent Effects of Barnidipine in Rat Vascular Smooth Muscle

Nawrath HKorstanje CJörg W. Wegener

subject

Malemedicine.medical_specialtyPatch-Clamp TechniquesVascular smooth muscleBarnidipineNifedipinechemistry.chemical_elementPharmacologyCalciumMuscle Smooth VascularRats Sprague-DawleyNifedipineInternal medicinemedicineAnimalsMyocyteCells CulturedPharmacologyChemistryDihydropyridineDepolarizationCalcium Channel BlockersRatsEndocrinologyMechanism of actioncardiovascular systemFemalemedicine.symptomCardiology and Cardiovascular Medicinemedicine.drug

description

The effects of the dihydropyridine nifedipine and its more lipophilic congener, barnidipine, were investigated in smooth muscle preparations from the rat in resting and depolarizing conditions. Both drugs relaxed precontracted aortic rings more potently in depolarizing conditions, barnidipine being more potent than nifedipine. Currents through Ca 2+ channels in rat vascular smooth muscle cells (A7r5) and in isolated rat cardiomyocytes were reduced more potently by both drugs at a holding potential of-40 mV than at -80 mV. However, barnidipine and nifedipine were more effective in reducing the current in A7r5 cells than in cardiomyocytes. The IC 50 obtained in aortic rings and in A7r5 cells were similar for barnidipine but an order of magnitude different for nifedipine. The results show that, in depolarizing conditions, barnidipine was more effective than nifedipine. It is suggested that the higher potency of barnidipine acting in vascular smooth muscle is related to both a higher affinity to the inactivated state of vascular Ca 2+ channels and to a more lipophilic property as compared with nifedipine.

yearjournalcountryeditionlanguage
2003-08-01Journal of Cardiovascular Pharmacology
https://doi.org/10.1097/00005344-200308000-00010