Table 2.

NAC decreases Ca²⁺ sensitivity while hastening cross-bridge kinetics

Parameter (Sample Size, Fibers)	NTg (n = 7)	NTg NAC (n = 6)	Tm-E180G (n = 7)	Tm-E180G NAC (n = 6)
Maximum tension, mN/mm2	36.07 ± 1.84	27.78 ± 4.18	33.06 ± 2.27	31.03 ± 3.54
pCa50 of tension	5.78 ± 0.01	5.55 ± 0.06*	6.01 ± 0.05**,††	5.84 ± 0.05†,§
Max ATPase, pmol·s−1·mg−1	379 ± 0.07	364 ± 14.02	351 ± 12.91	377 ± 0.71
pCa50 of ATPase	5.73 ± 0.05	5.68 ± 0.03	6.17 ± 0.07**,††	5.86 ± 0.09§
Tension cost	9.78 ± 0.74	12.63 ± 0.80**	9.41 ± 0.74††	11.13 ± 0.53**,§§
ktr Slope, s−1/(P/Po)	14.57 ± 0.81	22.98 ± 2.54**	14.15 ± 0.91††	23.47 ± 1.21**,§§
ktr (s−1) at minimum P/Po	3.76 ± 0.30	3.62 ± 0.88	3.17 ± 0.50	4.90 ± 1.02
ktr (s−1) at maximum P/Po	17.63 ± 0.74	28.20 ± 4.55*	13.77 ± 0.92††	27.93 ± 1.77*,§§

Values are means ± SE.

pCa₅₀, pCa at half-maximal tension; k_tr, kinetics of tension redevelopment.

^*P < 0.05 and

^**P < 0.001 vs. NTg;

^§P < 0.05 and

^§§P < 0.001 vs. Tm-E180G; †P < 0.05 and

^††P < 0.001 vs. NTg NAC.