Effects of morphine on acetylated histone 3 (ACH3) expression in spinal dorsal horns in complete Freund's adjuvant (CFA)-induced inflammatory pain (immunofluorescence microscope; fluorescent dyes: Alexa Fluor 488, Cy3, Hoechst).
(A) Effects of morphine on 50% paw withdrawal threshold in CFA-induced pain (aP < 0.01, vs. CFA 1 d).
(B) ACH3 expression in spinal dorsal horn in CFA 1 d (Ba) or CFA 1 d + Mor (B-b) (diaminobenzidine staining; scale bar: 200 μm).
(C) Quantitative analysis of ACH3 expression in spinal dorsal horn (two-way analysis of variance. aP < 0.01, vs. CFA 1 d group, n = 5).
(D) Double labeling of ACH3 with neuronal nuclei (NeuN), glial fibrillary acidic protein (GFAP) or CD11b in ipsilateral spinal dorsal horn, and quantitative analysis of double labeled cell number. Scale bar: 100 μm. (a, d, g) CFA 1 d; (b, e, h) CFA 1 d + Mor; (c, f, i) quantitative analysis of double-labeled cell numbers in a unit area of spinal dorsal horn. Data are expressed as mean ± SEM, one-way analysis of variance, Dunnett's test. aP < 0.01, bP < 0.05, vs. CFA 1 d group.
CFA 1 d: Day 1 after CFA injection; CFA 1 d + Mor: day 1 after CFA injection treated by morphine (Mor).