[Organic and inorganic blockers of potential-dependent Ca2+ channels inhibit store-dependent entry of Ca2+ into rat peritoneal macrophages].

The effect of organic and inorganic blockers of voltage-dependent Ca(2+)-channels on thapsigargin- and UTP-induced store-operated Ca(2+)-entry in Fura-2-loaded rat peritoneal macrophages was investigated. This store-dependent or "capacitative" Ca2+ influx stimulated by emptying the intracellular Ca(2+)-stores with endoplasmic Ca(2+)-ATPase inhibitor thapsigargin (0.5 microM) or purinergic agonist UTP (200 microM) is inhibited by the following pharmacological agents: two structurally distinct organic Ca(2+)-channel blockers nifedipine and verapamil; inorganic Ca(2+)-channel inhibitors Ni2+, La3+, Gd3+; nonselective cation channel blocker niflumic acid. Our data suggest that store-operated Ca2+influx channels of rat peritoneal macrophages share pharmacologic properties with L-type Ca(2+)-channels. Similar to trp-channels of Drosophila, they may resemble L-type Ca(2+)-channels lacking a voltage sensor.