Figure 5.

Regional distribution and cellular phenotypes of ObR(+) cells by immunohistochemistry. A, Specificity of the ObR immunofluorescence was shown by the absence of signals with inclusion of a blocking peptide. Left panel, ObR immunofluorescence was seen in a hypothalamic section from a B6 mouse. The signal was present in the cytoplasm of neurons and occasional astrocytes (arrowheads). Right panel, A blocking peptide (sc-1834p) was included at 5-fold m excess during the overnight incubation with the ObR antibody. This preabsorption step completely abolished the immunofluorescent signal (objective, ×20; scale bar, 50 μm). B, ObR expression between the B6 (A) and A^vy (B) mice differed in both neurons and astrocytes in the arcuate nucleus. The confocal microscopical images were taken with a 20× objective (scale bar, 50 μm). Seen at higher magnification (40× objective, scale bar, 30 μm), the B6 mouse (C) had fewer ObR(+) astrocytes (arrowheads) than the A^vy mouse (D). C, In the dorsomedial nucleus of hypothalamus (DMH), more cells and higher staining intensity of ObR(+) astrocytes were seen in the A^vy mouse (right panel) compared with the B6 control (left panel). D, The relative amount of ObR(+) astrocytes in the arcuate nucleus of the A^vy mice was significantly higher than that in the B6 mice. This was inversely correlated with the relative amount of neurons. ***, P < 0.005, comparison of the same cell type between B6 and A^vy; +++, P < 0.005, comparison of astrocytes and neurons of the same mouse strain (n = 3).