Fig. 5.

H89 (30 μm) blocked the effect of 1 mm 8 Br cAMP on Na⁺ current magnitude. At 20 min, the Na⁺ current in cells that had been pre- and cotreated with H89 (n = 6) was only 23% of that from cells treated with 8 Br cAMP alone (n = 5). By 60 min, the difference was even more pronounced because current magnitude continued to increase in cells treated with 8 Br cAMP alone (n = 4, one cell was lost before 60 min) but declined relative to baseline values with H89 treatment (n = 5, one cell was lost before 60 min).