Table 5.
Effects of microinjection of muscimol or glycine into the commissural nucleus tractus solitarii (commNTS) on thermogenic, metabolic, cardiovascular, and respiratory responses to ventilation with 8% O2
| Untreated commNTS | Inhibition of commNTS | |||
|---|---|---|---|---|
| Bic RPa | 8% O2 | Bic RPa | 8% O2 | |
| BAT SNA (% control) | 755 ± 134 | 286 ± 72* | 838 ± 259 | 749 ± 202† |
| BAT temp. (°C) | 34.7 ± 0.1 | 34.8 ± 0.1 | 35.0 ± 0.3 | 35.0 ± 0.3 |
| Expired CO2 (%) | 5.4 ± 0.2 | 5.3 ± 0.2 | 5.6 ± 0.2 | 5.4 ± 0.2 |
| HR (beats min−1) | 479 ± 6 | 487 ± 6 | 482 ± 5 | 467 ± 10 |
| MAP (mmHg) | 118 ± 9 | 144 ± 8* | 123 ± 13 | 97 ± 12*† |
| PHR amp. (% control) | 115 ± 7 | 146 ± 18* | 112 ± 13 | 122 ± 15* |
| PHR freq.(cycles min−1) | 45 ± 2 | 60 ± 3* | 60 ± 4* | 67 ± 4*† |
Values are means ± s.e.m. (n = 8) for physiological variables at the peak value within 5 min of the microinjection of bicuculline (Bic) into the RPa, the values during subsequent ventilation with 8% O2, the peak values after microinjection of Bic into the RPa plus muscimol or glycine microinjection into the commNTS, and the values during a subsequent episode of ventilation with 8% O2.
*
P < 0.05 compared to the preceding Bic-evoked response.
†
P < 0.05 for the hypoxia-evoked change compared to that in the NTS-untreated response.