Figure 1. Optogenetic control of MCH neurons.

(A) Pmch-CRE mice were mated to Rosa26-LSL-ChR2-YFP, and expression of ChR2-YFP (green—right panel) in MCH neurons (red—middle panel) in the LH are shown individually as well as in a merged panel (left panel); scale bar (Scale bar: 15 µm). (B) Quantification of co-expression of MCH and YFP shows that 97 ± 3% of MCH positive neurons expressed YFP and that 92 ± 8% of ChR2-YFP neurons expressed MCH (n = 1200 cells in four mice). (C) The effect of light stimulation on spike activity, evoked by light stimulation at 5 Hz, 10 Hz, and 20 Hz. (D) The response to 1 s continuous light stimulation, repeated 10 times. Inset, spike train in response to continuous light stimulation similar to what has been described for glucose-induced responses (see text for references and Figure 1—figure supplement 1 for quantification).

DOI: http://dx.doi.org/10.7554/eLife.01462.003

Figure 1—figure supplement 1. Optogenetic activation of MCH neurons.

(A) In voltage clamp mode, typical lightinduced ChR2 currents (n = 10, 1 ms pulse) and average amplitude of ChR2-induced inward currents. (B) Quantification of Figure 1D: left plot—continuous light stimulation generates a spiking rate of 20 ± 1.37 spikes/s (n = 20 light pulses). Right plot–Vm before, during and after continuous light stimulation shows that continuous light stimulation for 1 s depolarizes MCH neurons, which promptly recover to native membrane potential (Vm) upon termination of light pulses.

DOI: http://dx.doi.org/10.7554/eLife.01462.004