Fig 5. Effect of extracellular Ca²⁺ removal on the Ca²⁺ response to beractant.

A) Ca²⁺ signal elicited by beractant in the presence and absence of extracellular Ca²⁺ (0Ca²⁺) in the same single cell. Note that the prolonged decay phase did not occur in absence of extracellular Ca²⁺. B) Withdrawing extracellular Ca²⁺ (0Ca²⁺) during an established response to beractant (500 μg/ml) immediately interrupted the Ca²⁺ plateau and C) repetitive Ca²⁺ oscillations. The Ca²⁺ plateau and Ca²⁺ oscillations resumed upon readmission of external Ca²⁺.