Figure 1.

Reduced amygdala CRF₁, but not CRF₂, receptor binding in rats during acute ethanol withdrawal following chronic, intermittent ethanol vapor exposure. Panels show mean (± SEM) specific CRF₁ and CRF₂ binding in the central nucleus of the amygdala (CeA), medial nucleus of the amygdala (MeA), and basolateral amygdala (BLA) determined by quantitative autoradiography. Total specific binding of the CRF₁/CRF₂ receptor radioligand [¹²⁵I]-Tyr⁰-sauvagine was defined using a saturating concentration of the subtype-nonselective peptide antagonist D-Phe CRF_12–41 (10 mM). CRF₁ vs. CRF₂ receptor binding was defined using the highly selective nonpeptide CRF₁ antagonist R121919, in which residual specific binding of [¹²⁵I]-Tyr⁰-sauvagine that was not displaced by R121919 (1 mM) was defined as CRF₂ binding, and R121919-sensitive binding was defined as CRF₁ binding. Autoradiography was performed on coronal brain sections (20 µm) obtained from male Wistar rats during acute withdrawal (8 h) from a 28 day intermittent ethanol vapor inhalation procedure (n = 5; 14 h on; 10 h off; target blood alcohol levels, 200–225 mg%) and from air-exposed control rats (n = 5). Optical densitometry was performed using ImageJ (NIH), and values were normalized to prefabricated autoradiography microscales (Amersham).