Table 2.

Spinotrapezius muscle Po₂mv kinetics following the onset of contractions under control, SNP, and l-NAME conditions in sedentary and exercise-trained rats

	Control		SNP		l-NAME
	Sedentary	Trained	Sedentary	Trained	Sedentary	Trained
Po2mv(BL), mmHg	29.2 ± 1.3	27.8 ± 1.2	38.7 ± 2.3*	42.9 ± 3.5*	25.5 ± 1.7†	26.4 ± 1.5†
Δ1Po2mv, mmHg	11.4 ± 1.2	10.6 ± 0.8	9.3 ± 1.5	15.6 ± 3.3‡	13.0 ± 1.0	13.0 ± 1.2
Δ2Po2mv, mmHg	2.3 ± 0.3	2.5 ± 0.3			2.3 ± 0.4	2.8 ± 1.3
ΔTotalPo2mv, mmHg	9.8 ± 1.2	8.6 ± 0.8	9.3 ± 1.5	15.6 ± 3.3*‡	11.2 ± 0.9	12.1 ± 1.1
Po2mv(SS), mmHg	19.4 ± 1.0	19.2 ± 1.5	29.4 ± 1.5*	27.3 ± 1.4*	14.3 ± 0.8*†	14.2 ± 0.9*†
TD1, s	10.2 ± 0.7	10.3 ± 1.6	8.3 ± 1.6	11.8 ± 3.6	6.2 ± 0.5*	6.5 ± 0.9*†
TD2, s	55.1 ± 9.5	53.4 ± 12.4			55.0 ± 6.8	41.3 ± 7.2
τ2, s	39.5 ± 7.8	32.3 ± 10.1			55.5 ± 8.9	51.9 ± 18.9
MRT, s	18.3 ± 0.9	25.5 ± 3.3#	47.0 ± 5.8*	38.6 ± 5.2*‡	18.1 ± 1.7†	17.7 ± 1.6†

Values are means ± SE. Po₂mv, microvascular Po₂; Po₂mv_(BL), resting Po₂mv; Δ₁Po₂mv, amplitude of the first component; Δ₂Po₂mv, amplitude of the second component; Δ_TotalPo₂mv, overall amplitude regardless of one- or two-component model fit; Po₂mv_(SS), contracting steady-state Po₂mv; TD₁, time delay for the first component; TD₂, time delay for the second component; τ₂, time constant for the second component, MRT, mean response time. The time constant for the first component (τ₁) and relative rate of Po₂mv fall (Δ₁Po₂mv /τ₁) are shown in Fig. 3. The one-component exponential model was used to analyze the Po₂mv kinetics in the following conditions: sedentary control (6/18), sedentary SNP (14/14), sedentary l-NAME (3/14), trained control (2/10), trained SNP (9/9), and trained l-NAME (7/10). Significantly different from:

^*control within group;

^†SNP within group;

^‡sedentary within superfusion condition.

^#P = 0.13 vs. sedentary control.