We examined the effects of the calcium channel blockers nitrendipine, diltiazem, verapamil, bepridil, and mibefradil on the cloned HERG and KvLQT1/IsK K+ channels. These channels generate the rapid and slow components of the cardiac delayed rectifier K+ current, and mutations can affect them, which leads to long QT syndromes. When expressed in transfected COS cells, HERG is blocked in a concent...

The patch clamp technique was used to make whole-cell recordings of calcium channel currents from single muscle cells freshly isolated from rat mesenteric arteries. The cells were found to contain two types of calcium channels; one type is activated by small depolarizations and inactivates quickly, whereas the other requires stronger depolarizations for activation and inactivates more slowly. N...

PC12 cells, a clonal rat pheochromocytoma cell line, possess voltage-dependent calcium channels that bind the high affinity dihydropyridine calcium antagonist [3H]nitrendipine and other calcium channel blockers. The binding is temperature-dependent and saturable, and shows no cooperativity. The calcium antagonists inhibit potassium-induced 45Ca uptake into the cells with approximately the same ...

By fura-2 fluorometry, we investigated the direct effects of Ca2+ antagonists including a new benzothiazepine, clentiazem, on the high-K(+)-evoked increase in the concentration of cytosolic free Ca2+ ([Ca2+]i) in rat cerebral synaptosomes and cultured hippocampal neurons. In both preparations, metal ions inhibited the high-K(+)-induced increase in [Ca2+]i, in the following order: La3+ greater t...

The objective of the present work was to develop a suitable transdermal drug delivery system for nitrendipine. Polymeric films of nitrendipine were prepared by the film casting technique (glass ring) on mercury substrate. They were evaluated for physicochemical parameters, in vitro release and ex vivo permeation (heat separated human epidermis). Release of the drug from the films followed anoma...

A mucoadhesive drug delivery system for systemic delivery of nitrendipine, a calcium channel blocker through buccal route was formulated. Mucoadhesive polymers like hydroxypropylmethylcellulose K-100, hydroxypropylcellulose, sodium carboxymethylcellulose, sodium alginate, polyvinyl alcohol, polyvinyl pyrrolidone K-30 and carbopol-934P were used for film fabrication. The films were evaluated for...