Figure 3.

Effect of latrunculin B on shortening and relengthening in canine TSM after treatment with jasplakinolide. In the presence of 500 nM jasplakinolide, 30 nM latrunculin B did not affect FFIR or hysteresivity. Compared with jasplakinolide alone, latrunculin B treatment (in the continued presence of jasplakinolide) had similar minimal effects on isotonic shortening, spontaneous relengthening, force oscillation–induced relengthening, and hysteresivity when compared with initial control (pre-) isotonic contractions. These data indicate that stabilization of actin filaments with jasplakinolide prevented the effects of latrunculin B and further suggest a relation between actin filament length and FFIR in TSM strips. Data were compared using paired t tests. (Reprinted by permission from Reference 1.)