Materials were obtained as follows: DMEM/F12, reagent (TRIzol) and penicillin-streptomycin (Gibco-Invitrogen Corp., Grand Island, NY); fetal bovine serum (FBS; Atlanta Biologicals, Atlanta, GA); [1,3-3H] (+)-pentazocine (specific radioactivity, 37 Ci/mmol), [2,3-3H]-(+)-3-(3-hydroxyphenyl)N-(1-propyl)piperidine [3H]-(+)-3-PPP] (specific radioactivity, 92.4 Ci/mmol) (DuPont-NEN, Boston, MA); IgG-horseradish peroxidase (HRP; Santa Cruz Biotechnology, Santa Cruz, CA); Cy-3 IgG, 488-IgG, and 568-IgG (Alexa Fluor; Invitrogen, Carlsbad, CA); monoclonal anti-lamin A and monoclonal anti-PDI (Abcam Inc., Cambridge, MA); polyclonal antivimentin (Chemicon International, Temecula, CA); enhanced chemiluminescence (ECL) detection kit (Pierce Biotechnology, Inc., Rockford, IL); Bio-Rad Protein Assay Reagent (Bio-Rad, Hercules, CA); commercial blocker (PowerBlock; BioGenex, San Ramon, CA); protease inhibitors (Complete Mini Protease Inhibitor Cocktail tablets; GeneAmp RNA PCR Kit; Applied Biosystems/Roche Molecular System, Branchburg, NJ); DNA polymerase (TaKaRa Taq; Takara Bio Inc., Otsu, Shiga, Japan); sense and antisense primers for rat and mouse σR1 (Integrated DNA Technologies, Inc., Coralville, IA); (+)-3-PPP, carbetapentane, 1,3-di-(2-tolyl)guanidine (DTG), haloperidol, and phenytoin (Research Biochemicals, Natick, MA); (+)-pentazocine, anti–β-actin, 3-nitroso-N-acetylpenicillamine (SNAP), S-nitrosoglutathione (SNOG), 3-morpholinosydnonimine (SIN-1), hydrogen peroxide 30% (wt/wt) solution, xanthine, xanthine oxidase (X/XO), and all other chemicals (Sigma-Aldrich Chemical Co., St. Louis, MO). rMC-1 cells and RGC-5 cells were kind gifts, respectively, of Vijay P. Sarthy and Neeraj Agarwal. Anti-CRALBP was a generous gift of John Saari.