Nicotine Infusion in the Wake-Promoting Basal Forebrain Enhances Alcohol-Induced Activation of Nucleus Accumbens

Background Nicotine and alcohol co‐abuse is highly prevalent. Recently, we have shown that nicotine infusion in the basal forebrain (BF) increases alcohol consumption. As nucleus accumbens (NAc) is the terminal brain region associated with drug addiction, we hypothesize that nicotine infusion in the BF may enhance alcohol‐induced activation of NAc. Methods Adult male Sprague–Dawley rats were surgically implanted with bilateral guide cannulas in the BF. Following postoperative recovery, rats were divided into 4 groups: (i) ACSF + W group received artificial cerebrospinal fluid (ACSF; 500 nl/side) in the BF and systemic water (intragastric [ig]; 10 ml/kg; N = 5), (ii) ethanol (EtOH) group received ACSF in the BF (500 nl/side) and systemic alcohol (ig; 3 g/kg; N = 5), (iii) NiC group received nicotine in the BF (75 pmole/500 nl/side) and systemic water (ig; 10 ml/kg; N = 5), and (iv) NiC + EtOH group received nicotine in the BF (75 pmole/500 nl/side) and systemic alcohol (ig; 3 g/kg; N = 5). Rats were euthanized 2 hours after treatment to examine c‐Fos expression in the NAc by immunohistochemistry. Results All injections sites were localized in the BF. Two‐way analysis of variance (ig vs. infusion) revealed significant main effects of both treatments (ig and infusion, p