Table 1.
Effects of intravenous angiotensin II (ANG II) on the parameters of logistic functions and regression lines of the open-loop baroreflex characteristics
| Control 1 | Control 2 | ANG II | |
|---|---|---|---|
| Total baroreflex, CSP–AP relation | |||
| P 1 (mmHg) | 56.2 ± 7.2 | 56.3 ± 6.4 | 49.7 ± 6.2 |
| P 2 (mmHg−1) | 0.116 ± 0.019 | 0.118 ± 0.015 | 0.094 ± 0.013 |
| P 3 (mmHg) | 129.2 ± 3.5 | 124.5 ± 2.8 | 125.7 ± 3.2 |
| P 4 (mmHg) | 67.6 ± 4.6 | 69.7 ± 5.8 | 101.4 ± 10.9**,†† |
| Maximum gain | 1.57 ± 0.28 | 1.58 ± 0.22 | 1.20 ± 0.25 |
| Baroreflex control of HR, CSP–HR relation | |||
| P 1(beats/min) | 41.7 ± 5.1 | 43.9 ± 6.2 | 51.2 ± 3.8 |
| P 2 (mmHg−1) | 0.123 ± 0.027 | 0.133 ± 0.018 | 0.099 ± 0.013 |
| P 3 (mmHg) | 131.8 ± 3.8 | 125.8 ± 3.6 | 129.1 ± 2.6 |
| P 4 (beats/min) | 391.1 ± 13.7 | 388.0 ± 12.6 | 417.4 ± 11.5**,†† |
| Maximum slope (beats min−1 mmHg−1) | 1.11 ± 0.12 | 1.39 ± 0.23 | 1.28 ± 0.19 |
| Neural arc, CSP–SNA relation | |||
| P 1 (%) | 69.6 ± 5.7 | 66.5 ± 7.4 | 78.9 ± 9.1 |
| P 2 (mmHg−1) | 0.110 ± 0.016 | 0.124 ± 0.015 | 0.098 ± 0.011 |
| P 3 (mmHg) | 133.2 ± 3.8 | 127.3 ± 3.1 | 126.0 ± 3.4* |
| P 4 (%) | 33.3 ± 5.4 | 35.0 ± 6.4 | 56.5 ± 11.5*,† |
| Maximum slope (%/mmHg) | 1.94 ± 0.34 | 2.02 ± 0.33 | 2.04 ± 0.42 |
| Peripheral arc, SNA–AP relation | |||
| Slope, a (mmHg/%) | 0.85 ± 0.09 | 0.86 ± 0.06 | 0.66 ± 0.10 |
| Intercept, b (mmHg) | 37.8 ± 5.2 | 36.9 ± 5.5 | 68.0 ± 10.6**,†† |
| AP at 100% SNA (mmHg) | 122.7 ± 9.9 | 122.7 ± 7.0 | 134.4 ± 4.9 |
| Operating point | |||
| AP (mmHg) | 111.4 ± 5.0 | 110.3 ± 5.1 | 128.1 ± 4.4**,†† |
| SNA (%) | 90.6 ± 7.4 | 85.8 ± 2.1 | 94.3 ± 5.9 |
Data are mean and SE values
CSP Carotid sinus pressure, AP arterial pressure, HR heart rate, SNA sympathetic nerve activity
* P < 0.05 and **P < 0.01 from control 1, † P < 0.05 and †† P < 0.01 from control 2