Fig. 6.

Activation of store-operated Ca²⁺ entry (SOCE) in a flexor digitorum brevis fibre loaded with Fura-2 after sarcoplasmic reticulum (SR) depletion by high K⁺ exposures in the absence of external Ca²⁺ and in the presence of thapsigargin (TG) 5-10 μM. a Once depleted as shown by the absence of response to high K⁺, Ca²⁺ reintroduction in the external medium activates SOCE. The Ca²⁺ entrance can be reversibly blocked by 80 μM 2-APB. b When a similar protocol is applied to another fibre, but exposed to FCCP, SOCE cannot be activated again. It can be partially recovered after a long washout of the drug. This suggests that the mitochondrial depolarization affects the Ca²⁺ entry induced by SR depletion