Figure 2.

The effect of permeabilisation in the presence of the S2 fragment of myosin on contraction of rat ventricular myocytes

A, fast time base recordings of representative contractions averaged from 10 recordings obtained in control permeabilised (CP) and S2 permeabilised (S2) myocytes expressed as the change in cell length as a percentage of resting length (CP, 121 μm; S2, 106 μm). B, mean data showing resting cell length (Length), shortening as a percentage of resting cell length (Short), time to peak of the contraction (TTP) and time for half-relaxation (t_1/2) in control cells (□; n = 37), streptolysin O-permeabilised cells (;n = 60) and cells permeabilised in the presence of the S2 fragment of myosin (;n = 60). All values are expressed as means +s.e.m. as a percentage of that recorded in control cells. Control values for the parameters were: cell length, 108 ± 3 μm; shortening, 6.9 ± 0.7%; time to peak, 161 ± 7 ms; time to half-relaxation, 85 ± 5 ms. *P < 0.05; **P < 0.01 compared with control permeabilised cells (Student's t test with Bonferroni correction).