Fig. 5.

Pharmacological inhibition of PKA with H-89 abolished TBKCs and prevented caffeine-induced outward current in freshly isolated UBSM cells. A: an original voltage clamp recording illustrating that caffeine (10 mM), a ryanodine receptor (RyR) opener, transiently increased the outward currents and then abolished TBKCs in a single UBSM cell (n = 9, N = 6). B: an original recording illustrating that PKA inhibition with H-89 (10 μM) abolished TBKCs and that the subsequent activation of RyR with 10 mM caffeine did not induce any outward currents in single UBSM cells (n = 5, N = 5).