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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 3.

Figure 3

The total number of neurokinin-1 receptor (NK1R) immunoreactive neurons is increased in the rostral ventromedial medulla (RVM) of rats that received an intraplantar injection of complete Freund’s adjuvant (CFA) in the left hind paw four days earlier. (A) The rats were subdivided into those that underwent heat stimulation of both hind paws (SAL-T and CFA-T) and those that did not (SAL and CFA). The number of NK1R immunoreactive neurons was greater in both subsets of CFA-treated rats. (B) The rostro-caudal distribution of NK1R immunoreactive neurons in the RVM does not differ among any of the treatment groups. The ordinate is the cumulative number of NK1R immunoreactive neurons. The number of neurons was counted in five sections through the RVM beginning at the very caudal pole (section 1) and ending at the very rostral tip (section 5) of the VIIth motor nucleus. (C) Further subdivision of the data revealed that the number of NK1R immunoreactive neurons was increased in ipsilateral RVM of both subsets of CFA-treated rats. In the contralateral RVM the number of NK1R immunoreactive neurons was significantly greater in the group of CFA-treated rats that underwent heat stimulation when compared with the corresponding saline-treated group. Data are expressed as the mean ± S.E.M. of determinations in four rats in each treatment group. For all panels, * P < 0.05; ** P < 0.01 compared to the corresponding saline-treated group.