Fig. 6

Regional distribution of abundant TH + nerves in porcine spleen. Sections shown in A-E were developed using VIP purple chromogen, and section in F was developed using DAB brown chromogen and counterstained with hematoxylin. A Low magnification image showing sympathetic innervation in capsule (c) and nearby parenchyma. TH + nerve fibers are most evident in the capsule and red pulp (rp), although some also occur in the white pulp (wp). Trabeculae (t) extend from the capsule into the red pulp. B Higher magnification of white pulp region of panel A showing TH + nerves around the central arterioles of the white pulp and in the red pulp. C Image showing TH + nerves in the capsule extending toward the heavily innervated red pulp. D Central arterioles (indicated with arrows) are surrounded by TH + nerves that run in the adventitia and extend into the white pulp. E Image illustrating the contrast of innervation in the white pulp, red pulp, and trabeculae. Red pulp is heavily innervated throughout. Nerves in the white pulp mainly extend from the central arteriole. TH + nerves occur within and along trabeculae. Nerve bundles (nb) are also common in the parenchyma of pig spleens. F Brown TH + nerves in parenchyma near the capsule (c) and trabeculae (t). Arrow indicates central arteriole surrounded by nerves. Note nerves in trabecula exiting the capsule