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. 2017 Sep 20;11:66. doi: 10.3389/fncir.2017.00066

Figure 5.

Figure 5

Selective destruction of the LC noradrenergic neurons/terminals by systemic neurotoxin DSP-4 and its effects on the level of circulating NE, expression of DRG P2X3 and development of the empathic mechanical pain hypersensitivity in the CO rats. (A,B) Immunohistochemical images and averaged number of tyrosine hydroxylase (TH)-labeled neurons in the LC and the substantia nigra (SN) in rats treated with DSP-4 and saline (n = 3 for each group). (C) showing serum NE levels in the CC (n = 7) and CO rats with pre-treatment of i.p. saline (n = 6) or DSP-4 (n = 7), following 30 min social interaction. (D,E) showing representative immunoblotting bands and quantitative analysis of P2X3 expression in the L4-L5 DRG neurons of the CC and CO rats with pre-treatment of i.p. saline or DSP-4 (sample n = 3 for each group, however, each sample contains DRGs obtained from at least 9 rats), following social interaction. The relative value density for bands of P2X3 receptors of CO rats was normalized to that in CC rats. (F) showing effects of destruction of the LC noradrenergic neurons/terminals on development of the empathic mechanical pain hypersensitivity (n = 11 for both saline and DSP-4 group). CC, cagemate control; CO, cagemate observer; cp, cerebral peduncle; NE, norepinephrine; PWMT, paw withdraw mechanical threshold; RRF, retrorubral field; SN, the substantia nigra; TH, tyrosine hydroxylase; tth/ml, trigeminothalamic tract/medial lemniscus. #P < 0.05, ##P < 0.01, ###P < 0.001 DSP-4 vs. saline for CO; †P < 0.05 Saline CO vs. CC; ***P < 0.001 vs. pre-treatment. Scale bar for (A) 500 μm. Data are expressed as mean ± SEM.