Twenty-two-month-old female Sprague-Dawley rats (250–300 g; Harlan Industries, Inc., Indianapolis, IN) were housed in wire-bottom cages on a 12-h light/dark cycle and were allowed food and water ad libitum. Rats received continuous subcutaneous infusions of either nicotine bitartrate (3.15 mg/kg/day; expressed as the base) in saline (treatment group) or an equal volume of saline alone (control group) via osmotic minipumps for seven days (Malin 2001). Ten animals were used for the microarray experiment and ten for real-time PCR (RT-PCR) with five animals per group (i.e., control and nicotine-treated). All experimental protocols were approved by the Institutional Animal Use Committee at the University of Virginia.
