Table 1.
Firing rates of DRN serotonergic neurons recorded in control conditions and during the effect of bicuculline
| Vigilance state | Mean discharge rate (Hz) | Parameters of iontophoretic applications | |||
|---|---|---|---|---|---|
| Baseline | Bicuculline | Increase of discharge1-a | Current intensity (nA) | Ejection duration (sec) | |
| W | 1.56 ± 0.121-b | 4.44 ± 0.29*1-c | 2.88 ± 0.251-c | 80.0 ± 4.4 | 58.6 ± 6.3 |
| (184%)1-d | |||||
| SWS | 0.57 ± 0.061-b | 4.14 ± 0.29*1-c | 3.57 ± 0.301-c | 88.7 ± 4.1 | 60.7 ± 4.7 |
| (626%)1-d | |||||
| PS | 0.06 ± 0.021-b | 4.22 ± 0.36*1-c | 4.16 ± 0.371-c | 106.9 ± 8.2 | 64.8 ± 9.8 |
| (6933%)1-d | |||||
The increase of discharge, the intensity of current, and duration of the iontophoretic applications are summarized for each vigilance state.
The increase of discharge corresponds to the discharge rate under bicuculline minus the discharge rate in baseline conditions.
Statistical analysis of the discharge rate in control conditions using one-way ANOVA with the vigilance state as grouping variable showed a significant difference of the baseline firing rate between the three vigilance states (p < 0.001).
To assess the respective contribution of all experimental factors to the effect of bicuculline, the vigilance state (as qualitative variable), the baseline firing rate, the iontophoretic parameters (current intensity, duration of ejection), and combinations of all variables (crossed factors) were submitted to a multiple regression analysis (general linear model). No significant difference in the firing rate under bicuculline between W, SWS, and PS was evidenced by this procedure.
Average increase of the discharge rate expressed as a percentage.
*Value significantly different from baseline (p< 0.001).