Table 1.
Summary of numerical data of the in situ experiments and of 8-OH-DPAT effects in conscious rat. *p < 0.05; **p < 0.01; ***p < 0.001. Ttot, total respiratory cycle length; Ti, time of inspiration; Te, time of expiration; PNA ampl., phrenic nerve discharge amplitude; SCAi, sympathetic chain activity during inspiration; SCAe, sympathetic chain activity during expiration; PP, perfusion pressure; HR, heart rate; RR, respiratory rate; MABP, mean arterial blood pressure; sBRG, spontaneous baroreceptor reflex gain; HF, high-frequency pulse interval variations of BP, high–low pulse interval variations of BP; Var. HBI, variability of instantaneous heart beat interval; Var. PPF, variability of instantaneous pulse pressure fluctuation of BP.
| control | fentanyl | 8-OH-DPAT | naloxone | |
|---|---|---|---|---|
|
in situ experiments (mean ± s.d.) | ||||
| Ttot (s) | 3.6 ± 0.4 | 11.5 ± 2.6** | 4 ± 0.3** | 2.5 ± 0.4** |
| Ti (s) | 0.7 ± 0.1 | 2.3 ± 0.4** | 1 ± 0.1** | 0.7 ± 0.08** |
| Te (s) | 2.9 ± 0.3 | 9.3 ± 2.4** | 3 ± 0.4** | 1.8 ± 0.4** |
| PNA ampl. (µV) | 74.1 ± 14 | 28.7 ± 12.3** | 42 ± 13.7** | 46.9 ± 15* |
| SCAi (µV s) | 46. 5 ± 8.6 | 30.4 ± 6.5* | 36.8 ± 7.4a | 45.4 ± 9.8** |
| SCAe (µV s) | 44.3±8.4 | 28.4 ± 4.9** | 36.5 ± 7.8* | 42.0 ± 8.8** |
| PP (mm Hg) | 49.1 ± 3.1 | 45.2 ± 3.8a | 46.7 ± 3.5a | 47.4 ± 3.4a |
| HR (b.p.m.) | 299 ± 16.5 | 258 ± 24a | 201 ± 15.6* | 238 ± 12a |
| control | fentanyl | RS67333 | naloxone | |
| Ttot (s) | 3.8 ± 0.2 | 9.2 ± 0.7** | 5 ± 0.8** | 3.2 ± 0.7** |
| Ti (s) | 0.8 ± 0.1 | 1.9 ± 0.1** | 1.6 ± 0.2* | 0.8 ± 0.1** |
| Te (s) | 3 ± 0.2 | 7.3 ± 0.6** | 3.5 ± 0.6* | 2.4 ± 0.6** |
| PNA ampl. (µV) | 54.1 ± 3.4 | 38.6 ± 3.5** | 37 ± 5.2a | 50.3 ± 10* |
| SCAi (µV s) | 48.3 ± 12.5 | 36.6 ± 8.5a | 34.8 ± 9.5a | 45.0 ± 11.2a |
| SCAe (µV s) | 42.1 ± 11 | 37.2 ± 8.5* | 33.3 ± 9.5a | 40.1 ± 9.6a |
| PP (mm Hg) | 68 ± 8.8 | 58 ± 6.7a | 50 ± 6.7a | 58.8 ± 9.6a |
| HR (b.p.m.) | 305 ± 7.3 | 290 ± 16a | 248 ± 13* | 247 ± 25a |
|
in vivo experiments (mean ± s.d.) | ||||
| control | remifentanyl | 8-OH-DPAT | remifent. off | |
| RR (breaths min−1) | 70.2 ± 8.1 | 34.8±13.7** | 52 ± 16.7* | 60.5 ± 2.8** |
| Ti (s) | 0.12 ± 0.06 | 0.26 ± 0.08** | 0.15 ± 0.06** | 0.1 ± 0.08** |
| MABP (mm Hg) | 93.5 ± 3.2 | 78.1 ± 12** | 67 ± 10.7a | 86.1 ± 6.8** |
| HR (b.p.m.) | 353.8 ± 13.7 | 280 ± 88* | 277 ± 58a | 311 ± 22.8** |
| sBRG (ms mm Hg−1) | 1.28 ± 0.22 | 2.7 ± 0.5** | 3.5 ± 0.6a | 1.2 ± 0.3** |
| HF (ms2) | 12.9 ± 2.1 | 80 ± 11.6*** | 58 ± 16.3a | 22.4 ± 10.5** |
| HF–LF (ms2) | 0.46 ± 0.09 | 1.08 ± 0.07* | 0.84 ± 0.2a | 0.27 ± 0.06** |
| Var. HBI (ms) | 2.18 ± 0.2 | 103.8 ± 7.2*** | 55.8 ± 16.9* | 10.5 ± 5*** |
| Var. PPF (mm Hg) | 5.3 ± 0.4 | 139.5 ± 14.3*** | 53.5 ± 19.1** | 9.1 ± 3.2** |
aNot significant.