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
Distribution of i.c.v. EXN-4–induced Fos-IR in the brain and the adrenal gland. A series of photomicrographs demonstrates Fos-IR in neurons 2 hours after i.c.v. administration of EXN-4 (a–t, first and third columns; v–x) or PFS (a–t, second and fourth columns; u) in several brain regions and the adrenal gland. The brain regions include (a and b) the PVH; (c and d) the LHA; (e and f) the Arc/RCA; (g and h) the PBel; (i and j) the LC; (k and l) the A5; (m and n) the AP and the NTS; (o and p) the RVML; (q and r) the CVLM; and (s and t) the IML in the spinal cord. In the adrenal gland, after administration of PFS, little Fos-IR is visible (u). After i.c.v. EXN-4 at subthreshold dose (v; 3 μg), a little Fos-IR is visible. In contrast, i.c.v. EXN-4 at threshold dose (w; 30 μg) or a higher dose (x; 300 μg) induces Fos-IR in the adrenal medulla. Note that at the higher dose (x), Fos-IR is also visible in the cortex. Scale bar = 500 μm in a–d, g, and h; 200 μm in e, f, and i–t; and 50 μm in u–x.