Hiroshi Yamamoto, Charlotte E. Lee, Jacob N. Marcus, Todd D. Williams, J. Michael Overton, Marisol E. Lopez, Anthony N. Hollenberg, Laurie Baggio, Clifford B. Saper, Daniel J. Drucker, Joel K. Elmquist
EXN-4 activates medullary catecholamine neurons projecting to the spinal cord. (a–c) Double-label immunohistochemistry demonstrates that neurons that innervate sympathetic preganglionic neurons (brown cytoplasm) also contain i.c.v. EXN-4–induced Fos-IR (black nuclei) in (a) the PVH, (b) the Arc/RCA, and (c) the LHA of the hypothalamus. (d–f) Higher-magnification view of the boxed areas in a–c, respectively. (g–i) Double-label immunohistochemistry demonstrates that TH-immunoreactive neurons (brown cytoplasm) also contain i.c.v. EXN-4–induced Fos-IR (black nuclei) in (g) the NTS, (h) the LC, and (i) the CVLM. (j–l) Higher-magnification view of the boxed areas in g–i, respectively. (m–p) Triple-label immunohistochemistry reveals that many medullary catecholamine neurons (red cytoplasm in m and o) that project to the IML in the spinal cord (green neurons in n and p) also contain i.c.v. EXN-4–induced Fos-IR (black nuclei) in the RVLM (m and n) and the A5 (o and p). Scale bar = 100 μm in a–c and g–i, 25 μm in d–f and j–l, and 50 μm in m–p.