Wild-type mice were treated with vehicle or tubastatin (i.p.) followed by iv. Cy3-leptin. Mice were subsequently perfused and sections were prepared for imaging. a, Confocal images of Cy3 fluorescence (left) and the quantification of the fluorescence intensity (right) in the mediobasal hypothalamus (MBH) and the arcuate nucleus alone (ARC) (n=6). Arrowheads indicate Cy3-leptin. Scale bar: 20μm. b, c, Wild-type lean mice were implanted with a cannula in the lateral ventricle. Following 24-hr fasting, mice were treated with i.p. vehicle (n=6) or tubastatin (25mg/kg, n=6) and icv leptin (0.5μg per mouse). Food intake (16h P=0.027, 24h P=9.5E-3 by two-way ANOVA with Sidak correction (b) and 24hr body weight change (P=0.049 by unpaired two-tailed t-test) (c) was recorded. *P<0.05, **P<0.01, ***P<0.001. Data are represented as mean ± s.e.m.