Localization of BDNF mRNA and baroreceptor fibers in the fetal carotid sinus. Photomicrographs showing the localization of BDNF mRNA (A, B) and PGP-stained baroreceptor fibers (C, D) in adjacent sagittal sections through the E16.5 carotid sinus (CS).A and C pass through the lumen of the sinus and show BDNF mRNA (A) and baroreceptor fibers (C) in the adventitial layer of the sinus wall. B and D pass tangentially through the adventitial layer. BDNF mRNA labeling can also be seen over cells in the nodose ganglion (NG) in B. Note the higher magnification in C and D. Sections in A and B were counterstained with cresyl violet. CB, Carotid body;CCA, common carotid artery; SCG, superior cervical ganglion. Scale bars, 100 μm.