Ghrelin targets SNpc DA neurons and regulates nigrostriatal DA function. A1, Low-power image showing ghrelin binding in the SNpc using biotinylated ghrelin. A2, High-power image of the neurons indicated by arrows in A1. A3, Absence of binding in the SNpc when unbiotinylated ghrelin is used. Both biotinylated ghrelin and unbiotinylated are used at 10 nmol. SNr, Substantia nigra reticulata. Scale bars: A1, 30 μm; A2, A3, 10 μm. B, Ghrelin significantly increased SNpc DA action potential frequency above baseline (n = 11 DA cells identified by characteristic I
h currents). Data are presented as the mean ± SEM. aSignificant with respect to control, p < 0.05. Washout reduced ghrelin-elevated firing back to control levels. C, Representative action potential trace recordings from control, ghrelin, and washout conditions.