Functional dihydropyridine binding site associated with slow calcium channel in rat cultured neurones.

There is a high affinity binding of [3H]PN 200-110 (Kd = 0.21 nM) to slow calcium channels in cultured neurones. Several calcium antagonists, which recognize the [3H]PN 200-110 binding site, did not affect the K+-induced calcium uptake. The calcium channel activator BAY K 8644 increased the calcium uptake in depolarizing conditions and this effect was antagonized by pharmacological concentrations of calcium entry blockers. We conclude that the dihydropyridine binding site is involved in the modulation of calcium entry through the voltage-sensitive channel in depolarized cultured neurones.