Rebound depolarization of substantia gelatinosa neurons and its modulatory mechanisms in rat spinal dorsal horn
Abstract：Objective To investigate the rebound depolarization of substantia gelatinosa (SG) neurons in rat spinal dorsal horn and explore its modulatory mechanisms to provide better insights into rebound depolarization-related diseases.Methods Parasagittal slices of the spinal cord were prepared from 3-to 5-week-old Sprague-Dawley rats.The electrophysiologic characteristics and responses to hyperpolarization stimulation were recorded using whole-cell patch-clamp technique.The effects of hyperpolarization-activated cyclic nucleotide gated cation (HCN) channel blockers and T-type calcium channel blockers on rebound depolarization of the neurons were studied.Results A total of 63 SG neurons were recorded.Among them,23 neurons showed no rebound depolarization,19 neurons showed rebound depolarization without spikes,and 21 neurons showed rebound depolarization with spikes.The action potential thresholds of the neurons without rebound depolarization were significantly higher than those of the neurons with rebound depolarization and spikes (-28.7±1.6 mV vs-36.0± 2.0 mY,P＜0.05).The two HCN channel blockers CsC1 and ZD7288 significantly delayed the latency of rebound depolarization with spike from 45.9±11.6 ms to 121.6±51.3 ms (P＜0.05) and from 36.2±10.3 ms to 73.6±13.6 ms (P＜0.05),respectively.ZD7288 also significantly prolonged the latency of rebound depolarization without spike from 71.9±35.1 ms to 267.0 ± 68.8 ms (P＜0.05).The T-type calcium channel blockers NiC12 and mibefradil strongly decreased the amplitude of rebound depolarization with spike from 19.9± 6.3 mV to 9.5±4.5 mV (P＜0.05) and from 26.1±9.4 mV to 15.5±5.0 mV (P＜0.05),respectively.Mibefradil also significantly decreased the amplitude of rebound depolarization without spike from 14.3±3.0 mV to 7.9±2.0 mV (P＜0.05).Conclusion Nearly two-thirds of the SG neurons have rebound depolarizations modulated by HCN channel and T-type calcium channel.
Keywords：rebound depolarizationspinal dorsal substantia gelatinosa neuronshyperpolarization-activated cyclic nucleotide gated cation channelT-type calcium channelwhole-cell patch-clamp recording
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 204-209 )