Alterations in CRF₁ receptor function after chronic alprazolam treatment. a, Chronic alprazolam decreases CRF₁ receptor mRNA in the basolateral amygdala (BLA) and frontal/parietal cerebral cortex (F/P CTX). After 14 d of incorporation of alprazolam into the diet of male Sprague Dawley rats at a dose of 90 mg·kg⁻¹·d⁻¹, CRF₁ receptor mRNA expression was measured via densitometric analysis subsequent to in situhybridization in the BLA, cerebellum (CB), and F/P CTX. Eachverticalbar represents the mean ± SEM (n = 8 per group). Three to four slices were quantified per region per rat. *p < 0.05 and **p < 0.01 versus controls after analysis by a two-tailed t test. b, Chronic alprazolam decreases CRF₁ receptor-binding density in theBLA and CB. After 14 d of incorporation of alprazolam into the diet of male Sprague Dawley rats at a dose of 90 mg·kg⁻¹·d⁻¹, CRF₁ receptor binding was measured by densitometric analysis subsequent to receptor autoradiography performed in theCB, BLA, and F/P CTX. Total binding was determined using 0.1 nmol/l¹²⁵I-sauvagine. CRF_2A binding was determined in the presence of 1 μmol/l CP-154,526 (CRF₁-selective antagonist). Nonspecific binding was determined in the presence of 1 μmol/l sauvagine. CRF₁ receptor-specific binding was calculated as total binding − CRF_2A binding. Each verticalbar represents the mean ± SEM (n = 8 per group). Three to four slices were quantified per region per rat. *p < 0.05 and ***p < 0.001 versus controls after analysis by a two-tailed t test.