these variations were not due simply to differences in cell membrane area , which was estimated by cell membrane capacitance ( cm ) , because the density of ca2+ current ( dica = ica/cm ) also varied significantly from cell to cell ( 1.3-28 pa/pf at 0 mv ; mean +/- s.d . = 4.49 +/- 3.96 ; n = 152 ) .
C0007603
cell membrane
C0007634
cell