Corticosterone hemisuccinate

Drugs were dissolved in a 0.9% saline solution. Saline, isoflurane, and sodium brevital were from Butler Schein (Alsip, IL). Cocaine HCl and Yohimbine hydrochloride were from Sigma Aldrich (St. Louis, MO). Corticosterone Hemisuccinate was from Steraloids Inc. (Newport RI).

Alcohol (95%) was diluted in distilled water to a concentration of 20% (v/v) and administered IG, with volumes varied by weight to obtain the desired dose. Corticosterone hemisuccinate (4-pregnen-11β, 21-DIOL-3, 20-DIONE 21-hemisuccinate; Steraloids, Newport, RI) was dissolved in tap water by addition of NaOH and neutralized with HCl, to a final pH of 7.0–7.4 (Besheer et al., 2012 (link), 2013 (link); Gourley & Taylor, 2009 (link)). (1R,4R,5S,6R)-4-Amino-2-oxabicyclo[3.1.0]hexane-4,6-dicarboxylic acid disodium salt (LY379268; Tocris, Ellisville, Missouri), a highly selective (IC₅₀~10 nM in the presence of LY341495; Imre, 2007 (link)) Group II (mGluR2/3) agonist, and (2S)-2-Amino-2-[(1S,2S)-2-carboxycycloprop-1-yl]-3-(xanth-9-yl) propanoic acid disodium salt (LY341495; Tocris, Ellisville, Missouri), a highly potent (K_d~0.8 nM) and selective Group II (mGluR2/3) antagonist, were dissolved in saline and injected at a volume of 1 mL/kg. The doses of the mGluR2/3 compounds were selected based on pilot studies in our lab and on previous work (Bäckstrom & Hyytiä, 2005 (link); Cannady et al., 2011 (link); Liechti et al., 2007 (link); Monn et al., 1999 (link); Sidhpura et al., 2010 (link); Wright, Arnold, Wheeler, Ornstein, & Schoepp, 2001 (link)).