investigation of nicotine seeking behavior in current smokers

Conditions: Cigarette Smoking

Summary: in this study, 21 non-treatment-seeking cigarette smokers were recruited to investigate the effects of acute stress on brain function and nicotine seeking/self-administration behavior.

non-treatment-seeking cigarette smoking individuals were recruited from the detroit, mi area. individuals were screened for cardiovascular, neurological, and psychiatric contraindications. 21 healthy smokers completed two oral pre-treatment experimental sessions (on separate non-consecutive days) in randomized order under double-blind conditions: placebo (lactose) and stress (54mg yohimbine and 10mg hydrocortisone). yohimbine + hydrocortisone elicit a neurochemical and physiological response that mimics a 'natural' stressor. placebo and stress sessions were identical and started at 11am. upon arrival, subject sobriety was confirmed with expired breath alcohol measurement (\<.02%). at 11:30am, each subject smoked 6 cigarette puffs (preferred brand; provided by study) over 5 minutes to control for recent nicotine exposure. throughout each experimental session, subjects periodically completed self-reported measures of cigarette craving, nicotine withdrawal symptoms, affect, and anxiety, and vital signs were measured. subjects self-administered (swallowed) oral doses of yohimbine (or placebo) at 11:45am and hydrocortisone (or placebo) at 12:15pm. at 1pm, subjects completed a 60-min neuroimaging scan which included: 1) t1-weighted structural scan, 2) proton functional magnetic resonance spectroscopy (fmrs) acquisition from the left prefrontal cortex during a letter 2-back working memory paradigm, and 3) functional magnetic resonance imaging (fmri) acquisition during an n-back paradigm yoked with cigarette cues. at 2:30pm, subjects completed an 11-trial choice progressive ratio task in which they could earn cigarette puffs (preferred brand; provided by study) or money. at 3pm, subjects self-administered earned cigarette puffs (video monitored). subjects remained on site until 4pm discharge.

Eligibility criteria:
inclusion criteria: * 1) aged between 21-35 years old, 2) current smokers (expired breath carbon monoxide \> 4ppm, self-reported 10+ cigarettes/day, fagerstrom test for nicotine dependence score \> 3, 3) normal seated and resting vital signs (systolic blood pressure 80-160mmhg, diastolic blood pressure 50-90mmhg, and heart rate 50-90 bpm), and 4) normal or corrected-normal vision. exclusion criteria: * 1) abnormal electrocardiogram (reviewed by licensed cardiologist), 2) magnetic resonance imaging contraindications (e.g. metal implants), 3) medical/neurological contraindications (e.g., diabetes or head trauma), 4) pregnancy (urine test; females only), 5) positive urine test result for opioids, cocaine metabolites, benzodiazepines, barbiturates, or amphetamines, 6) psychiatric contraindications (subject met criteria for current axis 1 disorder \[other than nicotine dependence\] as indicated by computerized mini-6 screen), and 7) self-reported marijuana and/or alcohol use on 15+ days in the past month.

Keywords: cigarette smoking acute stress executive function craving nicotine seeking relapse excitatory neural activity glutamate negative affect