Figure 2.

POMC neurons release GABA and glutamate onto cells within the arcuate nucleus. Light-evoked IPSCs observed in the presence of DNQX (10 μm) (Ai) were abolished with the addition of BMI (10 μm) (Aii). Light-evoked EPSCs observed in the presence of BMI (Bi) were abolished with the addition of DNQX (Bii). C, An example of a cell with light-evoked IPSCs and EPSCs. Upon washout of DNQX and/or BMI evoked currents returned (Aiii, Biii, Civ). The images in A and B consist of three overlaid sweeps, whereas those in C are each an average of three sweeps. The transmitter(s) mediating evoked currents was determined in all cases in which a PSC was observed and is presented in D. E, A light-evoked IPSC in a POMC cell that also displays a direct ChR2 current (top trace). The evoked IPSC is ablated by BMI (bottom trace). F, Currents evoked onto an unidentified cell are completely inhibited by treatment with TTX (1 μm).