FIGURE 4.

Blockade effects of the μ‐opioid receptor (MOR) antagonist CTAP on β‐endorphin and DAMGO‐induced mechanical antiallodynia and thermal antihyperalgesia in the ipsilateral hind paws (A), inhibition of spinal excitatory synaptic transmission (B‐D), and effects on inhibitory synaptic transmission (E‐G) in neuropathic rats. Neuropathic rats were induced by ligation of spinal nerves. Representative mEPSCs and mIPSCs traces, cumulative distribution and statistical analyses were obtained from the lamina II spinal dorsal horn neurons. Scale bars, 40 pA and 10 s. Representative double immunofluorescence staining of MORs with the presynaptic and postsynaptic biomarkers Bassoon and PSD‐95 in the spinal dorsal horns from three normal rats (H). Scale bar: 100 μm. The data are presented as the means ± SEM (n = 6 animals per group). *p < 0.05, by one‐way or repeated‐measures two‐way ANOVA followed by Sidak's post‐tests)