Fig. 1

DAMGO induced decrease of mEPSC frequency was diminished after incubation with CCL2. A, E Application of DAMGO (1 µM, 3 min, n = 16) induced mEPSC frequency decrease that persisted during the wash-out period. B, E Pre-treatment with TRPV1 antagonist SB366791 (10 µM, 4 min, n = 8) did not significantly change the DAMGO-induced decrease of the mEPSC frequency. C, E Incubation of spinal cord slices with CCL2 (10 nM, 2 h) significantly attenuated DAMGO inhibitory effect (n = 11). D, E Inhibition of microglial activation by minocycline (100 µM) did not interfere with the CCL2 (10 nM, 2 h, n = 9) mediated attenuation of the DAMGO inhibition. F Mean mEPSC amplitudes were not significantly different between the experimental groups or after the DAMGO application. Statistical differences in each experimental group were identified using RM ANOVA on ranks followed by the Dunnett`s test; ^*P < 0.05, ^***P < 0.001 versus Ctrl/SB366791 part of the recording. Differences between the treatments were analyzed using one-way ANOVA followed by the Bonferroni test; ^˄P < 0.05, ^˄˄P < 0.01 versus CTRL group