Localization of ob-Rb protein expression in pressure-overloaded hearts. Immunohistochemical staining for ob-Rb protein (A, C, and E) and corresponding HE-stained sections (B, D, and F) of rat myocardium after aortic constriction. (A), (B): control heart; (C), (D): 2-week pressure-overloaded rat heart, and (E), (F): 4-week pressure-overloaded rat heart. Original magnification, x400 for (A) through (F). Bar=0.05 mm. Counterstaining was done with 2% methyl green.