Table 1.
Intrinsic membrane properties of DRN putative 5-HT and identified vlPAG GABAergic neurons
| Parameter | DRN Putative 5-HT neurons (n = 30) | vlPAG GABAergic neurons (n = 25) |
|---|---|---|
| Long diameter (μm) | 22.5 ± 0.5 | 16.7 ± 0.5*** |
| Short diameter (μm) | 14.7 ± 0.4 | 10.5 ± 0.4*** |
| RMP (mV) | −65.7 ± 1.0 | −62.3 ± 1.1* |
| Rin (MΩ) | 368.5 ± 37.4 | 508.1 ± 59.4* |
| Sag (%) | -- | 16.1 ± 3.4 |
| Sag decay τ (ms) | -- | 332.5 ± 58.8 |
| Sag decay Amplitude (mV) | -- | −12.1 ± 1.4 |
| Spontaneous firing (Hz) | 5.2 ± 0.7 (n=21/30) | 5.4 ± 0.5 (n = 14/25) |
| Maximum firing (Hz) | not tested | 47.3 ± 4.0 |
| AP amplitude (mV) | 69.5 ± 1.4 | 65.7 ± 2.7 |
| AP threshold (mV) | −51.6 ± 0.6 | −41.5 ± 4.4* |
| AP half width (ms) | 1.26 ± 0.05 | 0.85 ± 0.06*** |
| AHP amplitude (mV) | −26.9 ± 0.7 | −21.8 ± 1.4** |
p<0.0001;
p<0.01;
p<0.05;
unpaired t test, comparison between DRN and vlPAG neurons.
Note: The spontaneous firing rates of DRN putative 5-HT neurons in our study were higher than those of identified serotonergic neurons in rodents reported by other studies (Garduño et al., 2012), possibly due to 1) use of young animals in current study; 2) our use of a KCl-pipette solution for recording sIPSCs. vlPAG neurons were recorded with a K-gluconate based pipette solution. Abbreviations: RMP: resting membrane potential; Rin: input resistance; AP: action potential; AHP: afterhyperpolarization.