Figure 3. The CRF-induced decrease in evoked EPSP amplitude is mediated by CRF₁.

A) Top: Representative recordings of evoked EPSPs in a CeA neuron from a naïve rat recorded in control conditions, during Astressin B (AB) application, and during AB+CRF application. Bottom: Plot representing the percent peak decrease in evoked EPSP amplitudes for the middle three stimulus intensities during superfusion of AB and AB+CRF (7–8 cells from 7–8 naïve rats). CRF receptor antagonism decreases the evoked EPSP amplitude in naïve rats and blocks any further CRF-induced decrease. B) Top: Representative evoked EPSPs in a CeA neuron from a naïve rat recorded in control conditions, during R121919 (R12) application, and during R12+CRF application. Bottom: Plot representing the percent peak decrease in evoked EPSP amplitudes for the middle three stimulus intensities during superfusion of R12 and R12+CRF (9–20 cells from 9–17 naïve rats). CRF₁ antagonism decreases the evoked EPSP amplitude in naïve rats and blocks any further CRF-induced decrease. C) Top: Representative evoked EPSPs in a CeA neuron from a naïve rat in control conditions, during Astressin 2B (A2B) application, and during A2B+CRF application. Bottom: Plot representing the percent peak decrease in evoked EPSP amplitudes for the middle three stimulus intensities during superfusion of A2B and A2B+CRF (10 cells from 9 naïve rats). CRF₂ antagonism does not alter the evoked EPSP amplitude from baseline at the middle stimulus intensity in naïve rats, while co-application of CRF with A2B decreases the evoked EPSP. D) Histograms representing the percent peak decrease in evoked EPSP amplitudes for the middle stimulus intensity during superfusion of R12 and A2B show no difference between naïve and ethanol-dependent rats (Dep). E) Left: Representative PPF of EPSPs at 50 ms (top) and 100 ms (bottom) ISI in CeA neurons from an ethanol-dependent rat before and during superfusion of R12. Right: Histograms representing PPF ratio as a percentage of baseline after superfusion of R12 and A2B at 50 ms and 100 ms ISI in naïve and ethanol-dependent rats. R12 significantly increased the PPF ratio of evoked EPSPs for naïve rats at the 100 ms ISI. *p<0.05 from baseline by one-sample t-test.