Fig. 5.
SL-dependent changes in apparent cooperativity in force generation (nH) and Ca2+ sensitivity of force (pCa50) in WT and Ho rat skinned right ventricular trabeculae. Force-pCa relationships of WT (A; n = 13) and Ho (B; n = 11) rat skinned right ventricular trabeculae were determined first at short SL (2.00 μm; ●) and then at long SL (2.35 μm; ○). Solid lines were generated using the Hill equation described in methods and materials. Fitted values for nH and pCa50 for WT trabeculae were 2.94 and pCa 5.69, respectively, at short SL and 2.59 and pCa 5.81, respectively, at long SL and for Ho trabeculae were 2.86 and pCa 5.67, respectively, at short SL and 2.73 and pCa 5.72, respectively, at long SL. Inset: pCa50 values determined at short (black bars) and long (white bars) SL. Magnitude of SL-dependent changes in nH (C) and pCa50 (D) was determined by subtracting values recorded at short from those recorded at long SL. Data points are the means ± SE. #Significantly different from values determined in WT trabeculae.