Lack of hypertensive mechanism for central leptin in CD-fed lean mice. Male CD-fed C57BL/6 mice (with matched ages with HFD feeding) received the same surgical procedure as described in Figs. 1 and 2. After 1-week postsurgery recovery, mice received daily intra–third-ventricle injection of leptin for 2 days. On the second day of injection, mice were injected with SHU9119, KYN, or vehicle in the hypothalamic third ventricle 30 minutes prior to leptin injection. Curves on the left present the minute-by-minute average levels of (a) systolic, (b) diastolic, and (c) mean BP and (d) heart rate over a 4-hour postinjection period. Bar graphs on the right present average levels of (e) systolic, (f) diastolic, and (g) mean BP and (h) heart rate during early and late phases (35 to 65 minutes and 105 and 165 minutes postinjection) of leptin-induced hypertension in HFD-fed mice. Phase 1 (35 to 65 minutes) is outlined by a gray dotted line (a–d), and phase 2 (105 to 165 minutes) is outlined by a red dotted line (a–d). Error bars reflect mean ± standard error of the mean. n = 5 mice per group. aCSF, artificial cerebrospinal fluid; bpm, beats per minute; DBP, diastolic blood pressure; HR, heart rate; Inj & Rec, injection and recovery; Lep, leptin; MBP, mean blood pressure; SBP, systolic blood pressure; SHU, SHU9119.