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. 2019 Oct 17;4(20):e131712. doi: 10.1172/jci.insight.131712

Figure 10. In vivo intracolonic administration of pruritogenic agonists in CVH mice increases dorsal horn neuron activation in response to colorectal distension and alters animal behavior.

Figure 10

(A) CRD at a pressure of 40 mmHg in CVH mice results in activation of DH neurons within the thoracolumbar (T10-L1) spinal cord, as indicated by pERK-IR (yellow arrows). CVH mice pretreated with intracolonic CCDC (100 μM) display more DH neurons in the spinal cord following 40 mmHg CRD. Scale bars: 100 μm. (B) Group data showing that CVH mice pretreated with intracolonic CCDC (100 μM) displayed significantly more pERK-IR DH neurons within the spinal cord following 40 mmHg CRD compared with 40 mmHg CRD alone (****P < 0.0001, dots indicate individual counts in spinal cord sections from N = 6 CVH CRD and N = 6 CVH CCDC+CRD). (C) Representative track paths are shown for individual CVH mice administered either intracolonic vehicle (saline) or an itch cocktail consisting of a combination of CCDC (100 μM), BAM8-22 (20 μM), and CQ (10 μM). (D–F) Intracolonic administration of the itch cocktail to CVH mice significantly reduces (D) their track length covered within the central area of the observation enclosure (**P < 0.01; CVH + vehicle, N = 9; CVH + itch cocktail, N = 7) and (E) reduces their distance from the walls of the enclosure (*P < 0.05; CVH + vehicle, N = 9; CVH + itch cocktail, N = 7) compared with vehicle-treated CVH mice. (F) Intracolonic administration of the itch cocktail to CVH mice also significantly increased grooming behavior compared with CVH vehicle-treated mice (*P < 0.05; CVH + vehicle, N = 9; CVH + itch cocktail, N = 7). Data represent mean ± SEM. Dots represent values from individual mice. P values determined by unpaired t tests (B, D, E, F).