Selectivity of dihydropyridines for cardiac L-type and sympathetic N-type Ca2+ channels.

Article Details

Citation

Uneyama H, Uchida H, Konda T, Yoshimoto R, Akaike N

Selectivity of dihydropyridines for cardiac L-type and sympathetic N-type Ca2+ channels.

Eur J Pharmacol. 1999 May 28;373(1):93-100.

PubMed ID
10408255 [ View in PubMed
]
Abstract

The blocking effects of cilnidipine and other dihydropyridines on L-type cardiac Ca2+ channels (I(Ca,L)) and N-type sympathetic Ca2+ channel currents (I(Ca,N)) were studied using a whole-cell patch-clamp technique. At -80 mV, cilnidipine had little inhibitory effect below concentrations of 1 microM on I(Ca,L) (IC50 value; 17 microM). However, 1 microM cilnidipine strongly shifted the steady-state inactivation curve of I(Ca,L) toward negative potentials without changing the current-voltage relationship. Each action of cilnidipine was characterized by a high affinity for the inactivated channel in preference to the resting channel. The IC50 values of dihydropyridines for I(Ca,L) were in the range between 0.01 and 10 microM, and those for I(Ca,N) were between 3 and 30 microM. Cilnidipine had the strongest affinity for I(Ca,N) among the dihydropyridines tested. These results suggest that cilnidipine did not cause hypotension-evoked tachycardia deficiency by depression of cardiac L-type channels but by sympathetic N-type channels blockade.

DrugBank Data that Cites this Article

Drugs