Identification, characterization and stereotaxic mapping of intraneuronal alpha-melanocyte stimulating hormone-like immunoreactive peptides in discrete regions of the rat brain.
A highly specific antibody to alpha-melanocyte stimulating hormone (alpha-MSH) was used to histochemically localize and biochemically identify and quantitate alpha-MSH immunoreactivity in nerve fibers and cell bodies of the rat brain. alpha-MSH-like immunoreactivity was contained in fibers throughout the brain. The distribution of alpha-MSH was determined by immunocytochemistry as well as by radioimmunoassay combined with microdissection techniques. High concentrations of alpha-MSH were contained in the nucleus interstitialis stria terminalis, the median eminence and the medial preoptic, anterior hypothalamic, periventricular, paraventricular, arcuate, dorsomedial, and posterior hypothalamic nuclei. Moderate alpha-MSH concentrations were noted in the amygdala, septum, central gray, dorsal raphe, and the nucleus tractus solitarius. Cell bodies containing alpha-MSH were observed only in the arcuate nucleus. The alpha-MSH-like compound in brain had similar immunochemical and electrophoretic properties of standard alpha-MSH but high pressure liquid chromatographic analysis demonstrated that the alpha-MSH-like immunoreactivity was comprised of one major and two minor components. The major immunoreactive peak had an identical retention time as alpha-MSH and therefore may be chemically identical to alpha-MSH. The similar retention times and immunoreactivity of the other two compounds suggest a similarity in size and structure to alpha-MSH. These observations demonstrate that fibers containing alpha-MSH emanate from the arcuate nucleus to innervate many other regions of the rat brain.
D000818:Animals; D000906:Antibodies; D001923:Brain Chemistry; D006651:Histocytochemistry; D007016:Hypophysectomy; D007031:Hypothalamus / Q000032:analysis; D007118:Immunoassay; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000032:analysis*; D009474:Neurons / Q000032:analysis*; D010455:Peptides / Q000032:analysis*; D011863:Radioimmunoassay; D051381:Rats; D013238:Stereotaxic Techniques; D014018:Tissue Distribution
D000906:Antibodies; D010455:Peptides; D009074:Melanocyte-Stimulating Hormones