B, D. CCL2 effects on MCH neurons of MCH-CFP knock-in mice recorded in current-clamp mode. Representative trace of the effects of CCL2 on MCH neurons Discharge pattern of two representative MCH neurons in response to a depolarizing current pulse injection (current pulses applied every 10s) in control condition and in the presence of CCL2 (D). The control trace is recorded just before the application of CCL2 while the CCL2 trace is recorded 1 min after the beginning of CCL2 application. CCL2 delayed the third action potential (left panel) and induced failures in the action potential evoked in the right panel. 