Pharmacology of Capacitative Calcium Entry

Figure 2.

Gadolinium is a specific inhibitor that distinguishes between capacitative and non-capacitative calcium entry.^a

A. A single HEK293 cell (in Ca²⁺-containing medium) responds to the cholinergic agonist carbachol (5 μM) with repetitive spikes in cytosolic Ca²⁺ concentration; the subsequent removal of Ca²⁺ from the medium reveals these spikes to be dependent upon Ca²⁺ influx.

B. A single HEK293 cell (in Ca²⁺-containing medium) responds to the cholinergic agonist carbachol (5 μM) with repetitive spikes in cytosolic Ca²⁺ concentration that are not inhibited by Gd³⁺, thereby indicating that they involve a non-capacitative pathway.

^aData have been simplified from (24).

^bF₃₄₀/F₃₈₀ is the fluorescence shift of Ca²⁺ indicator Fura-2.