Charles J. Meliska

EEG, physiology, and task-related mood fail to resolve across 31 days of smoking abstinence: relations to depressive traits, nicotine exposure, and dependence.

Changes in task-related mood and physiology associated with 31 days of smoking abstinence were assessed in smokers, 34 of whom were randomly assigned to a quit group and 22 to a continuing-to-smoke control group. A large financial incentive for smoking abstinence resulted in very low participant attrition. Individuals were tested during prequit baselines and at 3, 10, 17, and 31 days of abstinence. Abstinence was associated with decreases in heart rate and serum cortisol, a slowing of electroencephalogram (EEG) activity, and task-dependent and trait-depression-dependent hemispheric EEG asymmetries. Differences between the quit group and the smoking group showed no tendency to resolve across the 31 days of abstinence. Trait depression and neuroticism correlated with increases in left-relative-to-right frontal EEG slow-wave (low alpha) activity at both 3 and 31 days of abstinence. In contrast, prequit nicotine intake and Fagerström Tolerance scores correlated with alpha asymmetry and with greater EEG slowing only at Day 3. Thus, the effects of smoking abstinence appear to last for at least several months.

Effects of smoking abstinence on mood and craving in men : influences of negative-affect-related personality traits, habitual nicotine intake and repeated measurements

Abstract A two-factor model of individual differences in smoking abstinence response was assessed. The two factors were nicotine bioadaptation (nicotine exposure and self-reported tolerance/dependence) and self-medication for negative affect/psychopathology. Bioadaptation was expected to promote transient increases in smoking abstinence-related negative affect, while self-medication was expected to be related to relatively permanent increases in negative affect. Of 56 male smokers starting, 50 completed the study, 30 of whom were randomly assigned to an immediate cessation group and 20 to a continuing-to-smoke control group. Mood and craving were repeatedly measured with the Profile of Mood States (POMS) and the Shiffman Withdrawal Questionnaire, administered twice per week during a three-week pre-quit baseline period and every 48 h during the 30-day abstinence phase. POMS negative moods decreased significantly across the six pre-quit baseline days even though there was no smoking cessation-related intervention during this time, a finding with implications for the question of whether quitters return to pre-quit levels of negative affect. Support for the two-factor model was provided by three of our findings. First, POMS Depression, Tension and Anger increased in the quit group after quitting and never returned to levels corresponding to the continuingto-smoke controls even after 30 days of abstinence. Second, trait depression assessed prior to smoking abstinence correlated with abstinence-related increases in POMS state depressive affect score shortly after quitting and during the last eight days of the study. Third, pre-quit cotinine concentration correlated with increases in negative affect during the first 48 h of abstinence. The findings suggest that previous studies should be interpreted with caution because of their failure to take into account the repeated-measures effect and selective attrition.

Immune function in cigarette smokers who quit smoking for 31 days

A group of 28 healthy, white, male, light-to-moderate smokers, 21 to 35 years of age, were offered a financial inducement to abstain from smoking for 31 days. A matched control group of 11 smokers were paid to continue smoking during the same period. Nonspecific parameters of immune system function were monitored before and at various times after smoking abstinence. Abstinence increased natural killer cell cytotoxic activity but did not alter mitogen-induced T-lymphocyte proliferation as measured by responses to concanavalin A or phytohemagglutinin. Serum cortisol concentrations also decreased after smoking cessation; however, changes in immune function were not correlated with serum cortisol change, nor with indices of smoking such as plasma nicotine and cotinine levels. Responses to concanavalin A and phytohemagglutinin were positively correlated with change in self-reported alcohol ingestion during smoking abstinence. Results indicate that elevation in natural kill cell cytotoxic activity is detectable within 1 month of smoking cessation, even in light-to-moderate smokers. However, elevation in natural killer cell cytotoxic activity appears not to be directly related to cessation-induced reductions in plasma nicotine, cotinine, or circulating cortisol levels.

Subjective correlates of cigarette-smoking-induced elevations of peripheral beta-endorphin and cortisol

Two experiments assessed subjective and hormonal effects of smoking cigarettes with three different nicotine deliveries. In experiment 1, 12 males smoked two cigarettes on three different occasions: (1) nicotine-free; (2) their own brand (1.0 mg FTC-estimated nicotine delivery); or (3) 2.4 mg FTC nicotine cigarettes. In experiment 2, 12 males smoked cigarettes of comparable nicotine yield using a quantified smoke delivery system (QSDS). Blood was sampled 2 min after each cigarette completion. Relative to nicotine-free smoking, plasma beta-endorphin (BE) and serum cortisol concentrations increased after quasi-ad libitum smoking of 2.4 mg, but not after 1.0 mg nicotine cigarettes. Self-reported malaise (nausea, sickness, and unpleasantness) also increased after smoking 2.4 mg nicotine cigarettes; subjective distress was correlated with changes in blood BE and cortisol, Smoking 1.0 mg cigarettes did not increase BE or cortisol, or subjective distress. QSDS smoking produced hormonal and subjective effects similar to quasi-ad libitum smoking; however, correlations between neuromodulator concentrations and mood were non-significant. These findings suggest that the elevated levels of plasma BE and cortisol reported in some smoking studies may not be characteristic effects of normal smoking.

Depression, personality, and gender influence EEG, cortisol, beta-endorphin, heart rate, and subjective responses to smoking multiple cigarettes

Abstract EEG, hormonal, and subjective effects of smoking multiple cigarettes were assessed in 8 males and 8 females who smoked their own habitual brand of cigarette on one occasion, a nicotine-free control cigarette via a quantified smoke delivery system (QSDS) on another occasion, and standard cigarettes by means of a QSDS on two other occasions. Smoking nicotine-containing cigarettes decreased drowsiness and delta and theta EEG magnitude while it increased serum cortisol. Nicotine enhanced beta2 magnitude significantly more in the right than left hemisphere. Nicotine-induced changes in serum cortisol, drowsiness, and EEG magnitude correlated with each other, such that increases in cortisol correlated with increased arousal. Prior to smoking, nicotine-deprived female smokers displayed more drowsiness and delta and theta EEG activity than males and female nonsmokers, but did not differ in this regard after smoking. Female smokers also reported more trait depression than other participants. Extraversion correlated positively with nicotine-induced decreases in drowsiness, theta, and alpha EEG magnitudes, while neuroticism and depression correlated negatively with these changes. BDI depression score correlated with greater nicotine-free baseline EEG activation of the right than left hemisphere. Nicotine tended to eliminate (normalize) this frontal EEG asymmetry that is characteristic of depressed individuals.

Characterization of a dose—response curve for nicotine-induced conditioned taste aversion in rats: Relationship to elevation of plasma β-endorphin concentration

In the first experiment a conditioned taste aversion paradigm was used to characterize a dose-response curve for the aversive properties of nicotine in male Sprague-Dawley rats. Doses of nicotine ranging from 0.01 to 0.46 mg/kg, 2.0 ml of 0.47 M lithium chloride, or saline were injected, ip, 10 min after exposure to a novel saccharin solution. Amount of saccharin consumed in a two-bottle test was assessed 72 h later. Nicotine doses of 0.046 mg/kg and above produced a significant degree of conditioned taste aversion. In a second experiment, four groups of 10 rats each were injected with saline, 0.022 mg/kg nicotine, 0.46 mg/kg nicotine, or 2.0 ml 0.47 of M LiCl. Doses of 0.46 mg/kg nicotine and 0.47 M LiCl elevated plasma beta-endorphin concentrations significantly above saline control values. The 0.022 mg/kg dose, the highest dose that did not produce conditioned taste aversion in Experiment 1, did not significantly increase plasma beta-endorphin concentrations. This finding suggests that doses of nicotine that produce conditioned taste aversion also promote the release of pituitary stress hormones. Taken together these data suggest that some of the pharmacological and behavioral effects attributed to nicotine, including the release of endogenous neuromodulators, may be dose-dependent concomitants of the aversive effects of nicotine in nicotine-naive animals.

Tolerance and sensitization to chronic and subchronic oral caffeine: Effects of wheelrunning in rats

Twenty-four male Sprague-Dawley rats were tested for wheelrunning in conjunction with chronic (continuous) or subchronic (alternate day) oral caffeine administration. As expected, chronic administration led to complete tolerance to caffeines locomotor stimulant effect, while subchronic administration produced sensitization. Results confirm earlier reports of enhanced stimulation with spaced administration of caffeine and tolerance with chronic administration.

A system for administering quantified doses of tobacco smoke to human subjects: plasma nicotine and filter pad validation

A new, automated system for administering quantified doses of cigarette smoke to human subjects is described and results of two studies demonstrating the reliability and validity of the system are presented. To overcome the large variability in nicotine and tar delivery associated with previous means of controlling smoke delivery, an automated quantified smoke delivery system was constructed. The system increases the precision and reliability of the smoke and nicotine dose delivered to human subjects. The quantified smoke delivery system was found to deliver doses of nicotine with a substantially greater degree of precision than procedures typically used in previous laboratory studies of smoking behavior.

Noise stress does not modulate effects of smoking/nicotine on β-endorphin, cortisol, ACTH, glucose, and mood

Abstract Noise-dependent effects of smoking multiple cigarettes on subjective state and blood concentrations of ACTH, β-endorphin, cortisol, and glucose were assessed in a repeated measures design where noise level (high versus minimal) was crossed with nicotine dose (quasi-ad lib own brand versus 1.0 mg FTC nicotine machine-delivered dose versus 0.05 mg FTC nicotine machine-delivered dose). Cortisol and ACTH were increased by nicotine, but not by noise and there was no noise by dose interaction. In contrast, nicotine did not increase β-endorphin in either noise condition and there was no dose by noise interaction for β-endorphin. However, noise was associated with a modest increase in β-endorphin. The effects of nicotine on blood glucose varied as a function of the number of cigarettes smoked. However, the effects of nicotine on glucose, hormones, and subjective state did not vary as a function of noise stress.

EFFECTS OF CAFFEINE- AND SUGAR-FREE BEVERAGES ON PSYCHOMOTOR PERFORMANCE '

Two cola beverages containing caffeine stimulated rope jumping more than beverages without caffeine; sugar content of the beverages did not appear to affect rope jumping by 36 college men.