Methanol bleaching abolishes labeling by mAb 3F11. (A) mAb 3F11 does not label samples bleached in methanol (12-16 hr). (B) mAb 3F11 labels the intestine in formaldehyde-fixed animals bleached in PBS (12-16 hr). Mg treatment also substantially improves 3F11 labeling in HCl-treated samples, but substantially reduces labeling in NAc-treated samples (B), demonstrating that some antibodies are uniquely sensitive to specific combinations of treatments. In all panels, anterior is to the left. Scale bars: 500 μm.