Fig. 1.
Response of intracellular pH (pHi) and cell shortening to methylcarbamyl-PAF (C-PAF). Aa: example record showing the rise in pHi induced by 200 nM C-PAF. Ab: summarized results (5 min, n = 23; 10 min, n = 16; 15 min, n = 5) showing the time course of increase in pHi induced by 200 nM C-PAF, expressed as ΔpHi (C-PAF minus control). Ac: relationship between ΔpHi at 10 min and C-PAF concentration (200 nM, n = 16; 50 nM, n = 6; 10 nM, n = 5; 1 nM, n = 7). The apparent EC50 is 0.9 nM. Inset shows response of 2 myocytes to 200 nM and 1 nM C-PAF. Ba: example record showing that 15 min superfusion with C-PAF (200 nM) had little effect on cell shortening (pacing cycle length = 2 s). Bb: summarized results for myocyte shortening showing no significant changes in cell shortening following 15 min of 200 nM C-PAF (n = 5, paired).