Mechanism of Catch Force: Tethering of Thick and Thin Filaments by Twitchin
Figure 5
The effect of cAMP on the mechanical responses of permeabilized ABRM following activation at high (pCa 5) (a) and intermediate (pCa 6) (b) concentrations of calcium, and the effect of cAMP on the relationship between isometric force and [Ca2+] in permeabilized ABRM (c). In (a) and (b), permeabilized muscles were incubated in relaxing solution, followed by activation with calcium for 10 minutes prior to addition of cAMP (100 M) for 6 minutes. In (c), muscles were treated in a cumulative manner with increasing concentrations of calcium. After a series of steady-state force measurements at a number of incrementing [Ca2+] were completed, a transition was made to calcium solutions containing cAMP. Force responses were normalized to the maximum force at pCa5 + cAMP. = 20 C. Reproduced from [63] with permission.
