Table 3.

Spinotrapezius muscle PO₂mv kinetics following the onset of contractions under control, SNP, and l-NAME conditions in CHF and CHF + EXT rats

	Control		SNP		l-NAME
	CHF	CHF + EXT	CHF	CHF + EXT	CHF	CHF + EXT
PO2mv(BL), mmHg	24.3 ± 2.3	22.6 ± 1.9	33.7 ± 2.3*	35.3 ± 2.9*	23.5 ± 2.4†	21.3 ± 1.0†
Δ1PO2mv, mmHg	10.3 ± 1.0	9.5 ± 1.1	8.8 ± 0.8	10.4 ± 2.1	11.9 ± 1.6	11.6 ± 1.0
Δ2PO2mv, mmHg	1.9 ± 0.3	2.2 ± 0.4			2.4 ± 0.4	2.3 ± 0.4
ΔTotalPO2mv, mmHg	8.8 ± 1.0	8.7 ± 1.0	8.8 ± 0.8	10.4 ± 2.1	9.7 ± 1.3	10.6 ± 0.8
PO2mv(SS), mmHg	15.5 ± 1.8	13.9 ± 1.2	24.9 ± 2.2*	24.9 ± 2.2*	13.7 ± 1.2†	10.7 ± 0.6*†
TD1, s	8.9 ± 1.5	12.6 ± 1.3#	4.0 ± 1.7*	5.7 ± 2.1*#	6.7 ± 0.7†	11.9 ± 2.1†‡
TD2, s	45.7 ± 5.7	83.3 ± 10.5			35.4 ± 4.7	60.5 ± 15.5
τ1, s	11.9 ± 1.3	19.7 ± 3.0#	39.0 ± 6.5*	49.8 ± 8.3*‡	10.1 ± 1.4†	19.1 ± 2.9†#
τ2, s	41.2 ± 12.6	57.0 ± 9.9			59.3 ± 9.1	38.0 ± 13.5
T63, s	20.4 ± 1.2	31.2 ± 2.3‡	42.2 ± 7.7*	55.0 ± 7.1*‡	17.4 ± 1.6†	31.3 ± 3.4†‡

Values are means ± SE. 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; τ₁, time constant for the first component; τ₂, time constant for the second component; T₆₃, time to reach 63% of the primary amplitude as determined independent of modeling procedures. The one-component exponential model was used to analyze the PO₂mv kinetics in the following conditions: CHF control (2/10), CHF SNP (10/10), CHF l-NAME (1/10), CHF + EXT control (7/10), CHF + EXT SNP (7/7), CHF + EXT l-NAME (5/11). Significantly different from:

^*control within group;

^†SNP within group;

^‡CHF within superfusion condition;

^#P = 0.05–0.1 vs. CHF within condition.