Functional and structural differences between skinned and intact muscle preparations

Figures

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  Figure 1.. Average myofilament spacing as a function of the sarcomere length in intact and relaxed skinned rat trabeculae, measured by x-ray diffraction. Adapted from Irving et al. (2000).

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  Figure 2.. Passive stress increasing with sarcomere length in skinned and intact rat ventricular trabeculae. The skinned results indicate enhanced mechanical compliance. Adapted from Kentish et al. (1986). Fig. 2 is reprinted with permission from Circulation Research.

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  Figure 3.. Comparing the force-calcium relationship in intact and skinned muscle. (a) Intact (ferret, 30°C; Yue et al., 1986) versus skinned (rabbit, 29°C; Harrison and Bers, 1989) muscle. (b) Pooled measurements derived from intact (solid symbols, pCa50 ≈ 6.21, n ≈ 4.9) and skinned (open symbols, 6.04, 3.8) preparations of the same rat ventricular myocytes. max, maximum. From Gao et al. (1994). Fig. 3 is reprinted with permission from Circulation Research.

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  Figure 4.. Active force generation in intact and skinned rat ventricular trabeculae as a function of sarcomere length, for different bath [Ca2+]. From Kentish et al. (1986). Fig. 4 reprinted with permission from Circulation Research.

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  Figure 5.. Dependence of the calcium sensitivity on sarcomere length. (a) Hill-type F-pCa for sarcomere lengths (SLs) = 1.85, 1.95, 2.05, 2.15, and 2.25 µm. Forces are normalized to the maximum force measured at SL = 2.05 µm. The data do not show a change in the Hill coefficient. (b) Increase in the Ca2+ sensitivity (decreasing [Ca2+] at half-maximum) with increasing SL, measured from the position of the inflection point in the fitted Hill curves from panel a. Adapted from Dobesh et al. (2002).

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  Figure 6.. Dependence of the force–calcium relationship on MgATP in the rat heart. (a) Decrease in Ca2+ sensitivity (increase in [Ca2+] at half-maximum) as [MgATP] increases from 30 to 100 µM ([Mg2+] = 50 µM). (b) Decrease in the maximum tension with increasing [MgATP]. Adapted from Best et al. (1977).

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  Figure 7.. Dependence of pH on the force-calcium relationship in guinea pig trabeculae. Adapted from Orchard and Kentish (1990).

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  Figure 8.. Dependence of generated tension on osmolarity. The osmolarity Γ/2 was controlled by varying (a) the Cl− salt (filled circles: KCl; open circles: NaCl; diamonds: TMACl; triangles: choline Cl) or (b) K+ salt concentrations (filled circles: KCl, filled squares: K propionate; open square: K Mes), for pCa = 3.8. The consistency between the results suggests that the tension depends predominantly on the ionic strength rather than on the size of specific ions. From Kentish (1984). Fig. 8 reprinted with permission from Journal of Physiology.

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  Figure 9.. Temperature dependence of the F-pCa relationship in skinned trabeculae from the rabbit ventricle, showing an increase in both the maximum tension Cmax and the sensitivity pCa50 (pCa at half-maximum) with increasing temperature. Adapted from Harrison and Bers (1989).