Figure 2. Summary of the effects of NO donors on the threshold β-adrenergic stimulation of I_Ca,L in rat ventricular myocytes.

A, mean stimulatory effects of various low concentrations of Iso on I_Ca,L, in the absence (filled bars) and in the presence of 1 nm SNAP (open bars). B, mean stimulatory effects of Iso (0.1–0.5 nm) in the absence (filled bars) and in the presence of different concentrations of SNAP or 2-(N,N-diethylamino)-diazenolate-2-oxide (DEANO; open bars). The amplitude of I_Ca,L in the presence of agonists was normalised to the amplitude of the basal I_Ca,L in the absence of agonists. Bars are the means and vertical lines are the s.e.m. of the number of experiments indicated near the bars. Significant differences from the Iso level: *P≤ 0.05; **P≤ 0.01; ***P≤ 0.005.