Table 4.
Effects of microinjection of saline into the commissural nucleus tractus solitarii (commNTS) on thermogenic, metabolic, cardiovascular, and respiratory responses to ventilation with 8% O2
| Untreated commNTS | Saline commNTS | |||
|---|---|---|---|---|
| Bic RPa | 8% O2 | Bic RPa | 8% O2 | |
| BAT SNA (% control) | 871 ± 203 | 319 ± 110* | 878 ± 417 | 262 ± 89* |
| BAT temp. (°C) | 35.2 ± 0.3 | 35.3 ± 0.3 | 35.5 ± 0.4 | 35.5 ± 0.3 |
| Expired CO2 (%) | 5.6 ± 0.3 | 5.4 ± 0.3 | 5.7 ± 0.4 | 5.6 ± 0.4 |
| HR (beats min−1) | 494 ± 13 | 501 ± 14 | 499 ± 10 | 520 ± 9 |
| MAP (mmHg) | 123 ± 12 | 142 ± 13* | 133 ± 9 | 150 ± 12* |
| PHR amp. (% control) | 114 ± 6 | 132 ± 9* | 117 ± 11 | 131 ± 13* |
| PHR freq. (cycles min−1) | 52 ± 4 | 62 ± 4* | 51 ± 4 | 62 ± 4* |
Values are means ± s.e.m. (n = 5) for physiological variables at the peak within 5 min of the microinjection of bicuculline (Bic) into the RPa, the value during a subsequent 30 s ventilation with 8% O2, at the peak after microinjection of Bic into the RPa following a saline microinjection into the commNTS, and the value during a second 30 s episode of ventilation with 8% O2. Note the Bic responses after saline injection into the commNTS did not differ from those in the untreated trial. In addition, the hypoxia-evoked responses did not differ between the untreated trial and the subsequent commNTS injected trial.
P < 0.05, compared to the immediately preceding Bic-evoked response.