Figure 2: Effect of intraportal injection (IPV) of leptin 100 pg on afferent activity of the hepatic branch of the vagus nerve. (a) Time course of afferent activity before and after injection. Vertical bar: 100 impulses/5 seconds. The arrow shows the time of injection. (b) Afferent discharge rate just before 30, 60, 90, and 120 minutes after injection. (c) Afferent nerve activity (A) just before injection, (B) 60 minutes, and (C) 110 minutes after injection. (d) Effect of IPV injection of leptin (100 pg, 0.1 mL) on mean discharge rates of vagal hepatic afferents ( ). *Shows significant increase in discharge rates from the control value just before injection.