Fig. 3.

Sympathetic activation in mice with short-term brain ER stress. (A–D) Mice received daily injections of TG (0.3 μg/d) or vehicle for 3 consecutive d. (A–C) At 2 h after the final injection on day 3, animals were anesthetized, and RSNA was recorded (A). n = 3–4 mice per group. The frequency of firing (B) and the spike amplitude (C) were both significantly different between TG- and vehicle-treated groups (P < 0.001). (D) Plasma norepinephrine (NE) concentrations of mice after 3-d TG (1.0 μg) or vehicle treatment. *P < 0.05; n = 7 mice per group. (E and F) C57BL/6 mice received daily third-ventricle injections of TG vs. vehicle (Veh) for 3 consecutive d, and the final injection was provided to overnight-fasted mice in combination with i.p. injection of prazosin (Prz, 1 mg/kg). At 2 h postinjection, mice were subjected to GTT (E) or blood sampling to measure plasma insulin concentrations (F). Data presented for GTT are the AUC values. NS, not significant; n = 8–9 mice per group. (G–I) Mice preimplanted with third-ventricle cannula and artery BP telemetric probes received daily third-ventricle injections of TG vs. vehicle (Veh) for 3 consecutive d, and the final injection was provided in combination with (+) or without (−) i.p. injection of prazosin (Prz, 1 mg/kg). Data represent average BP values over a 2-h period after the final injection. SBP, systolic BP; DBP, diastolic BP; MBP, mean BP. *P < 0.05; n = 4 mice per group. (Error bars reflect mean ± SEM.)