Figure 5 | Scientific Reports

Figure 5

From: Upregulation of Ih expressed in IB4-negative Aδ nociceptive DRG neurons contributes to mechanical hypersensitivity associated with cervical radiculopathic pain

Figure 5

Hypersensitivity to focal mechanical stimulation in IB4− Aδ type neurons from CRP rats.

(a) Focal mechanical stimulation was applied to the somata of IB4− Aδ neurons using a slow-moving heat-polished glass pipette (white arrow). Membrane deflection was observable by every stimulation (about 1/6 diameter of the neuron, 5–7 μm) for 1 s in duration. Response of the cell was recorded by a recording pipette (black arrow). (b) A typical example of the mechanical response in IB4− Aδ neuron from control and CRP rats. Inset is a magnification of response from CRP DRG neurons. (c) Representative examples of mechanically activated property of 3 different IB4− Aδ neurons from control and CRP group, respectively. Note that long-lasting afterdischarge was seen in 62.5% (5 out of 8) of DRG neurons tested in CRP group. (d) Firing frequency evoked by mechanical stimulation was much stronger in IB4− Aδ neurons from CRP rats as compared to that from control rats. (e) Quantitative analysis of duration of the high-frequent discharges to mechanical stimulation in control and CRP group. The durations were determined from the onset of the high-frequent discharges until spike frequency returned to pre-stimulus level. MS: mechanical stimulation. All data are expressed as mean ± S.E.M. *P < 0.05 as compared to control rats and #P < 0.05 as compared to basal level (ANOVA).

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