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Figure 3 | BMC Physiology

Figure 3

From: cAMP potentiates InsP3-induced Ca2+ release from the endoplasmic reticulum in blowfly salivary glands

Figure 3

InsP 3 -induced Ca2+ release is augmented by PKA activators and not by Epac activators. (A, C, D) Representative original recordings showing the effects of three cAMP analogs on InsP3-induced Ca2+ release as recorded by intraluminal Ca2+ measurements with Mag-Fura-2 in β-escin-permeabilized glands. (B, D, F) Summary of results obtained from experiments as illustrated in A, C and D. Ca2+ release is displayed as the change in the rate of the Mag-Fura-2 fluorescence ratio (ΔF340/F380·min-1) before and after addition of a cAMP analog as shown in (A), dotted lines. (A, B) The PKA and Epac activator 8-CPT-cAMP augments InsP3-induced Ca2+ release significantly in a concentration-dependent manner. (C, E) Neither 8-pMeOPT-2'-O-Me-cAMP nor the two other Epac activators (8-pHPT-2'-O-Me-cAMP and 8-pCPT-2'-O-Me-cAMP) has an effect on InsP3-induced Ca2+ release. 8-pCPT-2'-O-Me-cAMP was also ineffective in GTP-containing ICM (lowest two bars). (D, F) All three tested PKA activators (6-Phe-cAMP, 6-BNZ-cAMP, 6-MBC-cAMP) augment InsP3-induced Ca2+ release in a concentration-dependent manner. (B, E, F) Means ± S.D., paired t-test, *P < 0.05, **P < 0.01, ***P < 0.001.

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