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. Author manuscript; available in PMC: 2015 Sep 1.
Published in final edited form as: J Comp Neurol. 2014 Sep 1;522(13):3037–3051. doi: 10.1002/cne.23564

Figure 5.

Figure 5

The number of neurokinin-1 receptor (NK1R) immunoreactive neurons in the rostral ventromedial medulla (RVM) that exhibit internalization of the receptor is increased in rats that received an intraplantar injection of complete Freund’s adjuvant (CFA) and additionally underwent heat stimulation of the hind paws. Images in panels A and B are representative examples of NK1R immunoreactive neurons in the RVM of saline-treated rats that underwent heat stimulation. The neurons exhibit little to no internalization of receptor. Images in panels C–F are representative examples of NK1R immunoreactive neurons in the RVM of CFA-treated rats that underwent heat stimulation. Neurons with > 5 labeled endosomes were considered to have internalized the receptor. Images in panels A and C are projections of 3–4 stacks taken at intervals of 0.48 microns, while panels B, D, E and F are projections of 3–4 stacks taken at intervals of 0.41 microns. All scale bars are 20 microns. Panels G–I summarize the quantitative analysis. Data are expressed as the mean ± S.E.M. of determinations in four rats in each treatment group. * P < 0.05; ** P < 0.01 compared to the corresponding saline-treated group. † P < 0.05; †† P < 0.01 compared to the CFA-treated rats that did not undergo heat stimulation.