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Article: Afterhyperpolarization regulates firing rate in neurons of the suprachiasmatic nucleus.
Full Text (publisher's website) ; Article Metadata ; Article Data (extracted) Cloues RK; Sather WA J. Neurosci., 2003
Membrane properties of slow- and fast-firing cluster I neurons
| Depolarizing ramp (mV/msec) | Interspike potential (mV) | Spike width (msec) | Spike amplitude (mV) | Maximum hyperpolarization (mV) | AHP t½(msec) | Cd2+-subtracted AHP | IBTX-subtracted AHP | |||
|---|---|---|---|---|---|---|---|---|---|---|
| t½ (msec) | Amplitude (mV) | t½ (msec) | Amplitude (mV) | |||||||
| Number of cells (n) | 9 | 9 | 9 | 9 | 9 | 9 | 6 | 6 | 5 | 5 |
| Slow rate (<3 Hz) | 0.23 ± 0.01 | −41.3 ± 1.9 | 4.0 ± 0.1 | 82.8 ± 1.7 | −53.8 ± 1.6 | 37.3 ± 5.0 | 7.1 ± 0.9 | 11.0 ± 3.8 | 2.8 ± 0.8 | 17.4 ± 3.3 |
| Fast rate (>6 Hz) | 0.25 ± 0.03 | −44.7 ± 2.3 | 3.0 ± 0.1 | 77.7 ± 3.6 | −58.1 ± 2.2 | 17.8 ± 0.9 | 3.1 ± 0.4 | 26.0 ± 2.9 | 3.1 ± 0.7 | 10.4 ± 2.0 |
| p | NS | NS | 0.0001 | NS | NS | 0.001 | 0.003 | 0.01 | NS | NS |
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Membrane properties were compared between slow (<3 Hz) and fast (>6 Hz) spontaneously firing cluster I SCN neurons. The depolarizing ramp was measured as the rate of voltage change (mV/msec) over the 50 msec preceding action potential threshold. Interspike potential (V IP) was estimated as the plateau region between action potentials. For fast-spiking neurons in which interspike plateaus were mostly brief, V IP was estimated using the longer interspike intervals recorded from these irregularly firing neurons. Spike width was measured at action potential threshold. Spike amplitude was measured from V IP to maximum depolarization. Maximum hyperpolarization reached during the AHP was measured from 0 mV. t ½ for the AHP and Cd2+-subtracted AHP was estimated as the half-decay time. For measurements of Cd2+-subtracted AHPs, slow-firing cells included those firing at <5 Hz. Statistical significance (pvalues) for differences between fast- and slow-firing neurons is indicated at the bottom of each column, with p ≥ 0.05 considered not significant (NS).