Projection of pro-opiomelanocortin neurons from the rat arcuate nucleus to the midbrain central gray as demonstrated by double staining with retrograde labeling and immunohistochemistry.
Conjugate of horseradish peroxidase and wheat germ agglutinin (HRP-WGA conjugate) was injected into the midbrain central gray (MCG) of three adult rats. Frontal sections of the diencephalon were first treated with diaminobenzidine and hydrogen peroxide to detect the retrogradely transported conjugate. They were then stained immunohistochemically to detect pro-opiomelanocortin (POMC)-derived peptides (ACTH, beta-endorphin and alpha-MSH). The coexistence of the three POMC-derived peptides was confirmed by the immunohistochemistry of three consecutive sections stained with antiserum specific to each peptide. Some of the neuronal perikarya distributed in and around the arcuate nucleus were positive to the immunohistochemical stain for POMC-derived peptides, and, concomitantly, were labeled with HRP-WGA conjugate, which indicated that they projected to the MCG. They were mostly concentrated in the rostral three-fifths of the arcuate nucleus. The finding that some of the POMC neurons in the arcuate nucleus project to the midbrain central gray deserves interest, because the central gray is involved in analgesia induced by opioid peptides.
Yoshida
M
M
Department of Morphology, Gunma University, Maebashi, Japan.
Taniguchi
Y
Y
D000324:Adrenocorticotropic Hormone / Q000276:immunology; D000818:Animals; D000906:Antibodies / Q000276:immunology; D001111:Arcuate Nucleus of Hypothalamus / Q000166:cytology*; D006735:Horseradish Peroxidase; D007150:Immunohistochemistry / Q000379:methods; D008297:Male; D009474:Neurons / Q000648:ultrastructure*; D010487:Periaqueductal Gray / Q000166:cytology*; D011333:Pro-Opiomelanocortin / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D013194:Staining and Labeling / Q000379:methods; D014909:Wheat Germ Agglutinins; D000521:alpha-MSH / Q000276:immunology; D001615:beta-Endorphin
D000906:Antibodies; D014909:Wheat Germ Agglutinins; D000521:alpha-MSH; D001615:beta-Endorphin; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone; D006735:Horseradish Peroxidase