Figure 6.

Immunohistochemical characterisation of GCaMP6f cells in the Kit-Cre-GCaMP6f mouse IAS. (A–C) Dual labelling images of GCaMP6f cells in the internal anal sphincter (IAS) labelled with an anti-GFP antibody in combination with either c-Kit, platelet-derived growth factor receptor alpha (PDGFRα) or smooth muscle myosin heavy chain (smMHC) antibodies. Higher magnification images are shown in the bottom panels (Ad, Bd, Cd). GFP⁺ cells were neither PDGFRα⁺ (B) nor smMHC⁺ (C) but the majority (61.6 ± 2.6%, N = 11) were c-Kit⁺ (A). (D) Comparison of c-Kit⁺ cell density in wildtype mice (first bar) versus the density of c-Kit⁺ cells (second bar), GFP⁺ cells (third bar) and ‘all cells’ which includes all GFP⁺ cells plus cells that were c-Kit⁺/GFP⁻ (fourth bar) in Kit-Cre-GCaMP6f mice. The density of c-Kit⁺ cells in wildtype mice (N = 11) was significantly greater than in Kit-Cre-GCaMP6f mice (**P = 0.001) while wildtype c-Kit⁺ cell density was not different from the density of GFP⁺ cells (P = 0.727) or ‘all cells’ (P = 0.957) in Kit-Cre-GCaMP6f mice. Comparison of cell densities in Kit-Cre-GCaMP6f mice indicated that c-Kit⁺ cell density was significantly less than the densities of GFP⁺ cells (*P = 0.023) and ‘all cells’ (**P = 0.006). One-way ANOVA, post-hoc Tukey’s, N = 11.