Fig. 3

Facilitatory effects of KOR activation in CeA on spinal dorsal horn neurons were blocked by silencing CRF neurons in the CeA. Extracellular single-unit recordings of 10 spinal dorsal horn WDR neurons in anesthetized rats. a-c Peristimulus time histograms show action potentials (spikes) per second in an individual spinal WDR neuron before (pre-drug control in ACSF; A) and during administration of U-69,593 (100 μM in microdialysis probe, 15 min; B) into the CeA and during continued administration of U-69,593 while CRF-CeA neurons were silenced optogenetically (590 nm, 20 Hz, 1–5 mW, 3 min; C). Optical silencing of CRF-CeA neurons inhibited the facilitatory effects of U-69,593. d Time course of effects of U-69,593 in the CeA and optical silencing of CRF-CeA neurons on the same WDR neuron. e Summary of effects of U-69,593 in the CeA and optical silencing of CRF-CeA neurons on WDR neurons (n = 10). * P < 0.05, ** P < 0.01, compared to pre-drug ACSF; ⁺ P < 0.05, ⁺⁺ P < 0.01, compared to U-69,593 alone; ANOVA with Bonferroni posthoc tests. See text for results of ANOVA. Bar histograms show mean ± SE for the sample of neurons