Figure 7. CCE is enhanced, not inhibited, by AVP.

A7r5 cells were pretreated with 500 nM thapsigargin +1 μM ionomycin in Ca²⁺-free medium to deplete intracellular Ca²⁺ stores. (A) AVP-stimulated release of intracellular Ca²⁺ stores was estimated from fura 2 fluorescence (340:380 ratios) recorded from A7r5 cell populations during exposure to 100 nM AVP in Ca²⁺-free medium in untreated controls (upper trace) or cells pretreated with 500 nM thapsigargin +1 μM ionomycin (lower trace). These results demonstrate the effectiveness of the pretreatment for depletion of Ca²⁺ stores. (B) [Ca²⁺]_i was estimated from fura 2 fluorescence ratios (340:380) recorded during the reintroduction of extracellular Ca²⁺ (1.5 mM) without [arrow labelled ‘C’ or at various times (indicated below arrows) after the addition of 100 nM AVP]. Representative traces from individual coverslips are superimposed. Results are representative of three independent experiments.