Ntx hydrochloride

PRZ hydrochloride and/or NTX hydrochloride (Sigma-Aldrich, St. Louis, MO) were incorporated into pieces of sweetened gelatin as previously described (Froehlich et al., 2013a (link)). PRZ (2 mg/kg), NTX (10 mg/kg), PRZ+NTX (2 and 10 mg/kg, respectively), or vehicle (water) alone in approximately 1.8 g of gelatin (determined by BW of each rat) were fed to the rats once/day, 45 minutes prior to onset of the 2-h alcohol access period, and were confirmed to be consumed within 15 min. We previously reported that these PRZ and NTX dosages in gelatin suppressed 2-h alcohol drinking in male P rats without a history of prolonged unlimited alcohol drinking (Froehlich et al., 2013b (link)). The half-life of NTX in rats is 4 ± 0.9 h (Hussain et al., 1987 ); the half-life of prazosin in rats has not been determined, but is about 3 h in humans (Westfall and Westfall, 2006 ).

EtOH, Sucrose and sodium saccharin were used as drinking solutions. EtOH (99.8%) solutions (PanReac AppliChem, Barcelona, Spain) diluted to 5, 10, 20, 30 or 40% (v/v) were prepared in sterilized tap water. Sucrose solutions were prepared by dissolving ≥ 99.5% Sucrose (Sigma-Aldrich Química S.A. Madrid, Spain) in sterilized tap water to 5, 10, 20 or 40% (w/v). Sodium saccharine (Sigma-Aldrich, ≥ 98%) solutions at 0.13, 0.26, 0.53 or 1.06% (w/v) were dissolved in sterilized tap water. Concentrations of all drinking solutions were based on previous studies (Rhodes et al., 2005 (link), 2007 (link); Kamdar et al., 2007 ; Pastor et al., 2011 (link); Tarragón et al., 2012 (link)) as well as on our own pilot studies. In the case of EtOH, a direct study of the influence of availability of different concentrations and number of tubes was included in the present study (Experiment 1). NTX hydrochloride (Sigma-Aldrich) was diluted in 0.9% physiological saline and administered intraperitoneally (IP; 10 mL/kg injection volume). The dose range of NTX (4, 8 or 16 mg/kg) used in the present study was based on previous work (Kamdar et al., 2007 ; Tarragón et al., 2012 (link); Fultz et al., 2017 (link)).