(-)-Nicotine tartrate (MP Biomedicals, Solon, OH.) was dissolved in 0.9% saline. Nicotine was administered subcutaneously via osmotic minipumps (Alzet model 2002, Cupertino, CA) at a dose of 18 mg/kg/d for 14 days. This dose, reported as freebase weight and based off of previous work [16 (link), 21 (link)–23 (link)], corresponds to plasma levels of ~0.3 μM [24 (link)], a concentration similar to that observed in human smokers consuming an average of 17 cigarettes a day (plasma levels between 0.06 and 0.31 μM) [24 (link)].