Fig. 2

Facilitatory effects of KOR activation and inhibitory effects of CRF-CeA silencing on CeA neurons. Extracellular single-unit recordings of 19 neurons in the lateral and capsular CeA in anesthetized rats. a-b Peristimulus time histograms show action potentials (spikes) per second in an individual CeA neuron before (pre-drug control in ACSF) and during administration of U-69,593 (100 μM in microdialysis probe, 15 min) into the CeA. Background activity and evoked responses (see Materials Methods) increased. c Peristimulus time histogram shows effects of optical silencing of halorhodopsin expressing CRF-CeA neurons by yellow light pulses (590 nm, 20 Hz, 1–5 mW, 3 min) on action potential firing (see Materials and Methods, Optogenetics). d Time course of effects of U-69,593 in the same CeA neuron. e Summary of effects of U-69,593 in CeA neurons (n = 8).* P < 0.05, *** P < 0.001, compared to pre-drug ACSF, paired t-test. f Summary of effects of optical silencing of CRF-CeA neurons (n = 11). *** P < 0.001, compared to baseline before optical stimulation, paired t-test. e, f Bar histograms show mean ± SE for the sample of neurons