Figure 6.
Sympathetic innervation of the gastrointestinal tract is deficient in NGF-/-; Bax-/- mice. A-J, Whole-mount tyrosine hydroxylase immunostaining of the entire E16.5 gastrointestinal tract shows that mesenteric sympathetic axon projections (arrows) are present but diminished in NGF-/-; Bax-/- mice (B) as compared with NGF+/+; Bax-/- controls (A). Closer inspection of the proximal small intestine (C-F) demonstrates that sympathetic axons extend along the vasculature toward the small intestine (arrowheads) but do not fully innervate the organ in NGF-/-; Bax-/- mice (D, F) as compared with NGF+/+; Bax-/- controls (C, E) at both E16.5 (C, D) and P0.5 (E, F). The distal large intestine (G-J) also shows a reduction in sympathetic fiber density in NGF-/-; Bax-/- mice (H, J) as compared with NGF+/+; Bax-/- controls (G, I) at both E16.5 (G, H) and P0.5 (I, J). Scale bars: A, B, E, F, I, J, 250 μm; C, D, G, H, 100 μm.