Table 1.
Summary of all observed and calculated metrics for the DTA and IAA in response to KCl or PE using three experimental testing protocols. Data are presented as mean ± SEM.
| DTA | IAA | ||||||
|---|---|---|---|---|---|---|---|
| Uniaxial | Biaxial isometric | Biaxial isobaric | Uniaxial | Biaxial isometric | Biaxial isobaric | ||
| n = 7 | n = 6 | n = 7 | n = 7 | n = 5 | n = 5 | ||
| Unloaded passive configuration | |||||||
| Outer diameter (μm) | 946 ± 11 | 890 ± 32 | 929 ± 17 | 681 ± 8 | 645 ± 17 | 681 ± 15 | |
| Thickness (μm) | 120 ± 3.5 | 115 ± 2.8 | 125 ± 4.1 | 99 ± 3.9 | 100 ± 2.4 | 101 ± 3.9 | |
| Axial length (mm) | 0.87 ± 0.06 | 5.07 ± 0.14 | 5.28 ± 0.10 | 0.84 ± 0.05 | 5.58 ± 0.36 | 4.61 ± 0.12 | |
| Fixed loaded configuration for active testing | |||||||
| Axial stretch | 0.86 ± 0.01 | 1.46 ± 0.03 | 1.45 ± 0.02 | 0.91 ± 0.01 | 1.69 ± 0.02 | 1.64 ± 0.03 | |
| Potassium chloride | Loads and configurations | ||||||
| Relaxed pressure (mmHg) | — | 90 ± 0.0 | 90 ± 0.0 | — | 90 ± 0.0 | 90 ± 0.0 | |
| Pressure at maximal contraction (mmHg) | — | 120 ± 2.7 | 90 ± 0.0 | — | 112 ± 2.8 | 90 ± 0.0 | |
| Relaxed outer diameter (μm) | 1218 ± 33 | 1301 ± 46 | 1316 ± 17 | 803 ± 22 | 897 ± 18 | 909 ± 11 | |
| Outer diameter at maximal contraction (μm) | 1218 ± 33 | 1301 ± 46 | 983 ± 17 | 803 ± 22 | 897 ± 18 | 658 ± 17 | |
| Maximum change in outer diameter (%) | — | — | −25 ± 1.1 | — | — | −28 ± 2.3 | |
| Relaxed wall thickness (μm) | 104 ± 2.8 | 49 ± 2.0 | 55 ± 21 | 89 ± 4.0 | 38 ± 1.4 | 41 ± 2.0 | |
| Wall thickness at maximal contraction (μm) | 104 ± 2.8 | 49 ± 2.0 | 75 ± 3.0 | 89 ± 4.0 | 38 ± 1.4 | 60 ± 4.7 | |
| Stress calculations | |||||||
| Circumferential calculations | |||||||
| Relaxed circumferential stretch | 1.35 ± 0.03 | 1.62 ± 0.03 | 1.57 ± 0.03 | 1.22 ± 0.03 | 1.58 ± 0.03 | 1.50 ± 0.03 | |
| Circumferential stretch at maximal contraction | 1.35 ± 0.03 | 1.62 ± 0.03 | 1.13 ± 0.03 | 1.22 ± 0.03 | 1.58 ± 0.03 | 1.04 ± 0.06 | |
| Maximum change in circumferential stretch (%) | — | — | −28 ± 1.3 | — | — | −31 ± 2.8 | |
| Relaxed circumferential stress (kPa) | 30 ± 3.8 | 149 ± 9.2 | 133 ± 5.9 | 23 ± 5.4 | 132 ± 5.5 | 122 ± 5.7 | |
| Circumferential stress at maximal contraction (kPa) | 42 ± 4.1 | 197 ± 10.8 | 66 ± 3.5 | 35 ± 5.2 | 163 ± 3.1 | 54 ± 5.7 | |
| Maximum change in circumferential stress (kPa) | 13 ± 1.1 | 48 ± 4.0 | −68 ± 4.0 | 12 ± 0.5 | 31 ± 3.3 | −68 ± 4.4 | |
| Active circumferential force (mN) | 1.9 ± 0.1 | 3.9 ± 0.4 | 18 ± 1.0 | 1.7 ± 0.1 | 2.9 ± 0.4 | 14 ± 1.1 | |
| Axial calculations | |||||||
| Relaxed axial force (mN) | — | 12.0 ± 1.0 | 13 ± 0.5 | — | 5.9 ± 0.8 | 10 ± 0.5 | |
| Axial force at maximal contraction (mN) | — | 8.2 ± 1.1 | 15 ± 0.6 | — | 4.3 ± 1.0 | 10 ± 0.5 | |
| Maximum change in axial force (%) | — | 33.1 ± 4.5 | 7.6 ± 2.2 | — | 31.4 ± 8.8 | 0 ± 1.8 | |
| Relaxed axial stress (kPa) | — | 134 ± 7.3 | 127 ± 6.3 | — | 122 ± 10.8 | 147 ± 9.3 | |
| Axial stress at maximal contraction (kPa) | — | 138 ± 8.7 | 99 ± 5.6 | — | 121 ± 12.1 | 114 ± 9.1 | |
| Maximum change in axial stress (kPa) | — | 3.3 ± 1.6 | −27 ± 09 | — | −0.7 ± 1.8 | −32.3 ± 1.2 | |
| Dose–response parameters | |||||||
| Hill constant | −6.62 ± 0.31 | −11.29 ± 1.99 | 6.75 ± 0.32 | −7.16 ± 0.35 | −17.47 ± 3.36 | 7.90 ± 0.61 | |
| [EC50] (mM) | 39.62 ± 2.00 | 10.73 ± 1.03 | 23.58 ± 2.46 | 38.81 ± 1.17 | 14.03 ± 2.80 | 18.80 ± 0.86 | |
| Phenylephrine | Loads and configurations | ||||||
| Relaxed pressure (mmHg) | — | 90 ± 0.0 | 90 ± 0.0 | — | 90 ± 0.0 | 90 ± 0.0 | |
| Pressure at maximal contraction (mmHg) | — | 120 ± 2.5 | 90 ± 0.0 | — | 121 ± 2.4 | 90 ± 0.0 | |
| Relaxed outer diameter (μm) | 1218 ± 33 | 1314 ± 46 | 1329 ± 18 | 803 ± 22 | 917 ± 21 | 917 ± 14 | |
| Outer diameter at maximal contraction (μm) | 1218 ± 33 | 1314 ± 46 | 942 ± 39 | 803 ± 22 | 917 ± 21 | 479 ± 23 | |
| Maximum change in outer diameter (%) | — | — | −29 ± 2.3 | — | — | −48 ± 1.9 | |
| Relaxed wall thickness (μm) | 104 ± 2.8 | 48 ± 1.9 | 78 ± 3.2 | 89 ± 4.0 | 37 ± 1.3 | 84 ± 7.9 | |
| Wall thickness at maximal contraction (μm) | 104 ± 2.8 | 48 ± 1.9 | 119 ± 11.1 | 89 ± 4.0 | 37 ± 1.3 | 181 ± 18.7 | |
| Stress calculations | |||||||
| Circumferential calculations | |||||||
| Relaxed circumferential stretch | 1.35 ± 0.03 | 1.64 ± 0.02 | 1.59 ± 0.03 | 1.22 ± 0.03 | 1.62 ± 0.03 | 1.51 ± 0.03 | |
| Circumferential stretch at maximal contraction | 1.35 ± 0.03 | 1.64 ± 0.02 | 1.07 ± 0.03 | 1.22 ± 0.03 | 1.62 ± 0.03 | 0.68 ± 0.04 | |
| Maximum change in circumferential stretch (%) | — | — | −32 ± 2.6 | — | — | −55 ± 2.6 | |
| Relaxed circumferential stress (kPa) | 30 ± 3.5 | 152 ± 9.1 | 136 ± 4.6 | 24 ± 5.8 | 139 ± 6.3 | 124 ± 5.7 | |
| Circumferential stress at maximal contraction (kPa) | 40 ± 4.5 | 202 ± 9.9 | 59 ± 5.1 | 52 ± 7.2 | 185 ± 4.8 | 19 ± 3.7 | |
| Maximum change in circumferential stress (kPa) | 11 ± 1.4 | 50 ± 3.1 | −77 ± 5.7 | 28 ± 1.8 | 47 ± 2.0 | −105 ± 4.6 | |
| Active circumferential Force (mN) | 1.6 ± 0 2 | 4.0 ± 0.3 | 22 ± 2.0 | 3.7 ± 0.2 | 4.1 ± 0.3 | 26 ± 0.9 | |
| Axial calculations | |||||||
| Relaxed axial force (mN) | — | 10.5 ± 0.8 | 13 ± 0.4 | — | 5.5 ± 0.9 | 9 ± 0.6 | |
| Axial force at maximal contraction (mN) | — | 7.0 ± 0.7 | 15 ± 0.5 | — | 3.2 ± 1.1 | 10 ± 0.6 | |
| Maximum change in axial force (%) | — | 33.6 ± 1.2 | 18 ± 2.5 | — | 52.1 ± 15.0 | 17 ± 2.0 | |
| Relaxed axial stress (kPa) | — | 128 ± 7.7 | 124 ± 5.3 | — | 121 ± 12.9 | 140 ± 9.9 | |
| Axial stress at maximal contraction (kPa) | — | 134 ± 6.9 | 100 ± 5.0 | — | 120 ± 13.6 | 112 ± 10.0 | |
| Maximum change in axial stress (kPa) | — | 5.7 ± 1.7 | −24 ± 1.5 | — | −0.2 ± 1.0 | −27 ± 4.7 | |
| Dose response parameters | |||||||
| Hill constant | −3.16 ± 0.56 | −9.90 ± 2.45 | 2.73 ± 0.35 | −2.24 ± 0.12 | −6.28 ± 1.14 | 1.76 ± 0.07 | |
| [EC50] (nM) | 83.06 ± 17.75 | 14.59 ± 2.26 | 53.73 ± 11.08 | 509.92 ± 147.97 | 72.97 ± 8.42 | 303.56 ± 77.52 | |