Nicotine bitartrate was acquired from Interchem Corporation (Manchester, Connecticut). A research pharmacist at the VA CT Healthcare System prepared the nicotine samples. A total volume of 5 ml, containing either 0.5 mg or 1 mg/70 kg of nicotine, was injected intravenously over a 30-second interval via a catheter located in a forearm vein. The nicotine doses administered were within the range of nicotine delivered by smoking one cigarette. Our prior research demonstrated that these doses produced robust physiological and subjective responses in male and female smokers (22). The injections were given 30 minutes apart, which allowed subjective and cardiovascular responses to return to baseline levels (25–27). The genotyping was conducted after the experimental sessions were completed using a blinded method.
