Characteristics of ATPase and AMPase activity in the effluents of immediately after reperfusion. A: The first and second fractions (totally 40 sec after reperfusion) were pooled. Aliquots of 100 μl sample were preincubated for 5 min with saline (control), ouabain (Oua, 10 μM), levamisole (Lev, 500 μM), diethylpyrocarbonate (DEPC, 500 μM), ARL67156 (ARL, 50 μM) or α,β-MeADP (APCP, 10 μM, only in B), followed by adding ATP (100 μM, A) or AMP (100 μM, B). The reactions were performed at 37°C for 5 min in A or 30 min in B, and the substrates remained were measured by HPLC. Data shown are percentage of initial substrate levels. Values are means ± S.E.M (n = 5). *Significantly different from the control value at P < 0.05 by ANOVA, post-hoc Dunnett analysis.