Table 1
Effects of developmental nicotine exposure on whole XII nerve motor output in rhythmic medullary slices and on the intrinsic properties of XII motoneurons in caudal, nonrhythmic medullary slices
| Factor | Control | DNE | P Value | n |
|---|---|---|---|---|
| A. XII nerve motor output | ||||
| Inspiratory burst frequency, min−1 | 5.8 ± 0.6 | 6.3 ± 1.1 | 0.684 | 10/10 |
| Inspiratory amplitude, μV | 103.0 ± 0.2 | 96.0 ± 0.02 | 0.916 | 10/10 |
| Inspiratory duration, ms | 791.0 ± 50.0 | 653.0 ± 56.0 | 0.086 | 10/10 |
| B. XII motoneurons | ||||
| Resting potential, mV | −53.2 ± 1.8 | −54.4 ± 1.4 | 0.601 | 7/8 |
| Spike threshold, mV | −27.4 ± 1.8 | −31.4 ± 1.5 | 0.125 | 7/8 |
| Rheobase current, pA | 309.0 ± 34.0 | 143.0 ± 22.0* | 0.002 | 7/8 |
| Threshold current, pA | 351.0 ± 45.0 | 144.0 ± 22.0* | 0.003 | 7/8 |
| Maximum current, pA | 1,479.0 ± 122.0 | 594.0 ± 38.0* | 0.0002 | 7/8 |
| Minimum frequency, Hz | 10.4 ± 1.4 | 8.2 ± 1.0 | 0.230 | 7/8 |
| Maximum frequency, Hz | 48.0 ± 5.6 | 35.4 ± 1.7 | 0.067 | 7/8 |
| Frequency-current gain, Hz/pA | 0.050 ± 0.004 | 0.087 ± 0.012* | 0.016 | 7/8 |
| Input resistance, MΩ | 78.6 ± 9.70 | 131.9 ± 13.7* | 0.008 | 7/8 |
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Values are means ± SE, n = number of animals, with control before the forward slash and DNE after it. XII, hypoglossal. Inspiratory frequency and the amplitude and duration of XII motor nerve bursts represent average values taken during a 2-min recording period. The definition of the intrinsic cellular properties measured in XII MNs is given in methods.
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↵* Significant difference between control and DNE.