The distribution and projection of gamma-melanocyte stimulating hormone in the rat brain: an immunohistochemical analysis.
The distribution and projection of immunoreactive gamma-melanocyte-stimulating hormone (gamma-MSHI) in the rat brain was examined by indirect immunofluorescence using an antiserum against synthetic rat gamma-MSH. The present study confirmed the presence of gamma-MSHI neurons in the arcuate nucleus and further demonstrated that the n. commissuralis is a new gamma-MSHI neurons-containing site. We also found a gamma-MSHI fiber network in the hypothalamus, thalamus, amygdala, central gray matter of the midbrain and upper pons, and further demonstrated a much more extensive distribution of these fibers particularly in the medulla oblongata, an area previously thought not to contain gamma-MSHI structures. The present observation on the normal distribution of gamma-MSHI suggested the existence of two different systems: one is the arcuatofugal gamma-MSH system and the other n. commissuralis gamma-MSH system. Using experimental manipulations, we clearly established that gamma-MSHI fibers in the forebrain, diencephalon, midbrain and upper pons originate from gamma-MSHI neurons in the arcuate nucleus and those in the medulla oblongata from the n. commissuralis .
D000818:Animals; D001921:Brain / Q000378:metabolism*; D001931:Brain Mapping; D004027:Diencephalon / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D008526:Medulla Oblongata / Q000378:metabolism; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism*; D008636:Mesencephalon / Q000378:metabolism; D009434:Neural Pathways / Q000378:metabolism; D011149:Pons / Q000378:metabolism; D051381:Rats; D013687:Telencephalon / Q000378:metabolism
D009074:Melanocyte-Stimulating Hormones