Figure 1.

Experimental Design. Animals arrived on postnatal day 21 and were housed in groups of four for one week. Following this, animals were randomly assigned to housing conditions, and either remained group housed (GH n = 33) or were socially isolated (SI n = 35) for the remainder of their adolescent development. At the end of six weeks, anxiety-like behavior and locomotor activity were assessed using the elevated plus-maze and open field tests. After this, 57 animals (GH n = 28; SI n = 29) were individually housed and began intermittent two-bottle choice ethanol self-administration in their home cages. A subset of animals (GH n = 13; SI n = 14) also underwent fear conditioning and extinction learning prior to ethanol access. All animals were allowed to self-administer ethanol on this schedule for eight weeks. A separate subset of animals (GH n = 15; SI n = 16) were used to determine blood ethanol concentrations three weeks into the drinking study. At the end of eight weeks, animals began receiving injections of either prazosin, propranolol, or duloxetine once per week to assess the dose-dependent effects of these drugs on drinking. Animals were sacrificed at the end of these studies.