Maternal nicotine exposure and fetal programming of vascular oxidative stress in adult offspring

Despite the well-known harmful effects, many women continue to smoke throughout pregnancy. Consequently, nicotine replacement therapy (NRT) - which has been developed as a pharmacotherapy for smoking cessation - has been used as an alternative to smoking during pregnancy. However, like cigarette smoking, NRT results in biologically significant levels of nicotine crossing the placenta, leading to both fetal and neonatal exposure to nicotine, and yet, NRT safety during pregnancy has not been extensively evaluated. There is now evidence from studies in rats that maternal nicotine exposure throughout gestation results in fetal programming of vascular oxidative stress in the offspring during adulthood. This phenomenon involves vascular dysfunction mediated by reactive oxygen species in association with decreased superoxide dismutase activity and increased Nox2-NADPH oxidase expression in the vascular wall. If this phenomenon also occurs in humans, either smoking or NRT use during pregnancy may represent a novel risk factor for the unborn that results in accelerated cardiovascular disease in their adulthood.     

Nicotine dose-concentration relationship and pregnancy outcomes in rat: biologic plausibility and implications for future research

Cigarette smoke (CS) exposure during pregnancy can lead to profound adverse effects on fetal development. Although CS contains several thousand chemicals, nicotine has been widely used as its surrogate as well as in its own right as a neuroteratogen. The justification for the route and dose of nicotine administration is largely based on inferential data suggesting that nicotine 6 mg/kg/day infused continuously via osmotic mini pumps (OMP) would mimic maternal CS exposure. We provide evidence that 6 mg/kg/day nicotine dose as commonly administered to pregnant rats leads to plasma nicotine concentrations that are 3-10-fold higher than those observed in moderate to heavy smokers and pregnant mothers, respectively. Furthermore, the cumulative daily nicotine dose exceeds by several hundred fold the amount consumed by human heavy smokers. Our study does not support the widely accepted notion that regardless of the nicotine dose, a linear nicotine dose-concentration relationship exists in a steady-state OMP model. We also show that total nicotine clearance increases with advancing pregnancy but no significant change is observed between the 2nd and 3rd trimester. Furthermore, nicotine infusion even at this extremely high dose has little effect on a number of maternal and fetal biologic variables and pregnancy outcome suggesting that CS constituents other than nicotine mediate the fetal growth restriction in infants born to smoking mothers. Our current study has major implications for translational research in developmental toxicology and pharmacotherapy using nicotine replacement treatment as an aid to cessation of cigarette smoking in pregnant mothers.     

Recommendations for the use of pharmacological smoking cessation strategies in pregnant women

Maternal smoking during pregnancy causes significant fetal morbidity and is a public health problem, as 36% of women in the UK and 11% of those in the US smoke during pregnancy. Behavioural support for smoking cessation, provided outside of routine antenatal care, is effective for promoting smoking cessation by pregnant women, but relatively few pregnant women access such support. Effective pharmacological aids to smoking cessation, which have been trialled in nonpregnant populations, include nicotine replacement therapy (NRT), bupropion and varenicline; however, there is very little evidence to justify the use of these drugs in pregnancy. Also, for safety reasons, it is doubtful that definitive trials investigating the effectiveness of either bupropion or varenicline for smoking cessation will be conducted in pregnant women in the foreseeable future. In the short to medium term, research information relating to the use of these drugs in pregnancy is, therefore, likely to be derived from observational studies that are more difficult to interpret than clinical trials. This article assesses the evidence for the effectiveness and safety of using NRT, bupropion and varenicline for smoking cessation during pregnancy. The principle recommendations made are that NRT may be safer than smoking in pregnancy, and pregnant women who have unsuccessfully tried to stop smoking without pharmacotherapy may consider using NRT in subsequent quit attempts after informed discussion with their doctor. There is no evidence, however, that NRT is actually effective for smoking cessation in pregnancy. With currently available evidence, bupropion and varenicline cannot be recommended in pregnancy for smoking cessation.     

Nicotine and nonnicotine factors in cigarette addiction

Rationale A great deal of research supports the role of nicotine in cigarette addiction. However, the effectiveness of nicotine replacement therapy (NRT) as a smoking cessation treatment has fallen short of initial hopes. A key reason may be that NRT does not address nonnicotine components of smoking reinforcement. These include constituents that provide reinforcing sensory stimulation, components that minimize excessive irritation from inhaled nicotine and other pharmacologically active compounds in cigarette smoke. Objective Studies using various paradigms to dissociate nicotine from other components of smoking are summarized. Results Nonnicotine components provide many rewarding effects, often surpassing the direct effects of nicotine. Substitutes for the sensory effects of smoking may be effective in relieving craving for cigarettes and in facilitating smoking cessation. Moreover, techniques for devaluing smoking-related cues may decrease craving and enhance subsequent abstinence. Promising approaches for devaluing smoke cues include extinction-based treatments employing denicotinized cigarettes and the use of nicotinic agonist and/or antagonist treatment during the weeks leading up to a quit attempt. Recent studies suggest that incorporating these approaches into a treatment program may significantly increase smoking abstinence rates. Preliminary findings also suggest that replacement of the effects of monoamine oxidase inhibitors contained in cigarette smoke may enhance quit rates. Conclusions While current NRT methods have been the mainstay of smoking cessation treatment and will likely continue to serve a useful role, the next stage of progress will likely entail the development of tools designed with recognition of the importance of nonnicotine components of cigarette smoking.     

If nicotine is a developmental neurotoxicant in animal studies, dare we recommend nicotine replacement therapy in pregnant women and adolescents?

Tobacco use in pregnancy is a leading cause of perinatal morbidity and contributes in major ways to attention deficit hyperactivity disorder, conduct disorders and learning disabilities that emerge in childhood and adolescence. Over the past two decades, animal models of prenatal nicotine exposure have demonstrated that nicotine is a neurobehavioral teratogen that disrupts brain development by preempting the natural, neurotrophic roles of acetylcholine. Through its actions on nicotinic cholinergic receptors, nicotine elicits abnormalities of neural cell proliferation and differentiation, promotes apoptosis and produces deficits in the number of neural cells and in synaptic function. The effects eventually compromise multiple neurotransmitter systems because of the widespread regulatory role of cholinergic neurotransmission. Importantly, the long-term alterations include effects on reward systems that reinforce the subsequent susceptibility to nicotine addiction in later life. These considerations strongly question the appropriateness of nicotine replacement therapy (NRT) for smoking cessation in pregnant women, especially as the pharmacokinetics of the transdermal patch may actually enhance fetal nicotine exposure. Further, because brain maturation continues into adolescence, the period when smoking typically commences, adolescence is also a vulnerable period in which nicotine can change the trajectory of neurodevelopment. There are also serious questions as to whether NRT is actually effective as an aid to smoking cessation in pregnant women and adolescents. This review considers the ramifications of the basic science findings of nicotine's effects on brain development for NRT in these populations.     

Effects of Nicotine During Pregnancy: Human and Experimental Evidence

Prenatal exposure to tobacco smoke is a major risk factor for the newborn, increasing morbidity and even mortality in the neonatal period but also beyond. As nicotine addiction is the factor preventing many women from smoking cessation during pregnancy, nicotine replacement therapy (NRT) has been suggested as a better alternative for the fetus. However, the safety of NRT has not been well documented, and animal studies have in fact pointed to nicotine per se as being responsible for a multitude of these detrimental effects. Nicotine interacts with endogenous acetylcholine receptors in the brain and lung, and exposure during development interferes with normal neurotransmitter function, thus evoking neurodevelopmental abnormalities by disrupting the timing of neurotrophic actions. As exposure to pure nicotine is quite uncommon in pregnant women, very little human data exist aside from the vast literature on prenatal exposure to tobacco smoke.     

Toxicological overview of cigarette smoking on angiogenesis

Angiogenesis is the process of generating new capillary blood vessels. It occurs under tight regulation in the female reproductive system, during wound healing and during embryogenesis. Angiogenesis also plays an important role in the pregnancy-associated changes in the reproductive tract. Cigarette smoke inhibits processes that may hinder normal process of angiogenesis resulting in abnormal blood supply to tissues, decreased repair and remodeling. This report summarizes the evidences of the causal association between tobacco smoking and disruption of angiogenesis. Application of small amount of nicotine on day 5 old chorioallantoic membranes (CAMs) did not disrupt the process of angiogenesis, while application of mainstream smokes (MSS) solutions to CAMs caused varying levels of disruption on normal process of angiogenesis and adversely affect capillary plexus formation, diameters of secondary and tertiary vessels. We have also observed that at equivalent doses, sidestream smoke (SSS) can significantly be more potent than MSS and can alter the normal process of angiogenesis more drastically than MSS. It suggests that SSS either contains a toxicant(s) not present in MSS or that the toxicant(s) that produces these effects is present in higher concentration in SSS than in MSS. Therefore, it is undisputed that smoking can interfere the normal process of angiogenesis, which is a vital process to maintain pregnancy and development of fetus. Smoking during pregnancy is harmful to fetal development and is associated with an increased risk of miscarriage, perinatal death and sudden infant death syndrome. Smoking-cessation programs remain a crucial strategy for preventing poor birth outcomes and decreasing the social and financial costs of smoking during pregnancy.     

Smoking during pregnancy: lessons learned from epidemiological studies and experimental studies using animal models

Numerous epidemiological studies in the human population clearly indicate that smoking while pregnant has deleterious effects on fetal development as well as long-term adverse consequences on postnatal development and maturation of several organ systems. Low birth weight, sudden infant death syndrome (SIDS), behavioral disorders including attention deficit hyperactivity disorder (ADHD), externalizing and internalizing behavioral problems and conduct disorders in children have all been linked to prenatal exposure to tobacco smoke. The major pharmacologically active chemical found in tobacco smoke is nicotine, and prenatal exposure to nicotine has been shown to have significant effect on the development of multiple organ systems, including the nervous, respiratory, and cardiovascular systems. In this review, we define mainstream and sidestream smoke, summarize the major classes of compounds found in cigarette smoke, and describe how use of laboratory animal models can be used to assess mechanisms of toxicity and risk in the human population in general. We then discuss the association with smoking during pregnancy and the occurrence of reduced lung function, low birth weight, the incidence of congenital structural malformations, SIDS, ADHD, cognitive impairment, and mood disorders in children, and review pertinent experimental studies using a variety of animal models of developmental nicotine exposure, including, rats, mice, monkeys, lambs, and pigs that have increased our understanding of the pathophysiology of these disorders.     

Effects of topiramate on cue-induced cigarette craving and the response to a smoked cigarette in briefly abstinent smokers

Rationale Clinical studies have shown that topiramate, an anticonvulsant medication, may be effective as a treatment for smoking cessation. However, less is known about topiramate effects on nicotine withdrawal and craving and its interactions with a smoked cigarette. Objectives The objective of this study was to investigate the effects of topiramate treatment on abstinence-related nicotine withdrawal, cue-induced cigarette craving, and the acute effects of a smoked cigarette. Materials and methods Fifteen female and 25 male cigarette smokers were randomly assigned to 9-day treatment with topiramate (final titration dose, 75 mg/day) or placebo. On the last day of treatment, after a 3-h smoke-free abstinence period, participants were evaluated for symptoms of nicotine withdrawal and then underwent cigarette and neutral cue reactivity testing. Thirty minutes after completing cue exposure testing, participants were then evaluated for the acute effects of a smoked cigarette. Cue reactivity and acute smoking measures included subjective ratings of cigarette craving and withdrawal and physiological measures of skin conductance and temperature, heart rate, and blood pressure. In addition, smoking topography was measured using a puff volume apparatus. Results Topiramate treatment enhanced subjective ratings of withdrawal after the 3-h abstinence period and reduced pre-cue skin conductance levels. Cigarette cue exposure resulted in a moderate increase in craving, which was unaffected by treatment. Topiramate treatment enhanced the rewarding effects of a smoked cigarette, even while participants smoked less per puff and achieved lower plasma nicotine levels. Conclusion Results suggest that topiramate enhances both nicotine withdrawal and reward. These findings question the utility of topiramate treatment for smoking cessation.     

吸烟对个体肌肉组织发育的影响及其机制

烟草烟雾(CS)中含有过千种有害物质,如尼古丁、多环芳烃(PAHs)、一氧化碳(CO)、氮氧化合物、醛类等。吸烟危害个体肌肉组织的发育。母亲孕期吸烟,香烟中的有害物质被母体吸入后,可通过胎盘屏障直接毒害胎儿,也可以通过损伤胎盘结构,进而间接影响胚胎发育。孕期吸烟与胎儿骨骼肌肌量减少、宫内生长障碍、出生低体重、儿童发育迟缓、先天性膈疝等疾病有关。青少年吸烟可能会导致心律不齐、心肌梗死等疾病。长期吸烟能引起骨骼肌肌肉萎缩、少肌症。本文综述了吸烟对个体肌肉组织发育的影响及其可能的机制。     

Fetal and neonatal exposure to nicotine disrupts postnatal lung development in rats: role of VEGF and its receptors

Many women are unable to quit smoking during pregnancy and therefore are prescribed drugs, including nicotine (nicotine replacement therapy [NRT]), to aid with smoking cessation. However, the consequences to the offspring of pregnant NRT users have not been well studied. The goals of this study were to determine the consequences of fetal and neonatal exposure to nicotine on lung development and function. Female rats were exposed to nicotine for 2 weeks prior to mating until weaning. Lungs were collected from saline and nicotine-treated rats from birth to adulthood to assess postnatal lung structure and function. Although nicotine exposure altered alveolarization at weaning, an effect that resolved by adulthood, it did not affect lung function at any of the ages investigated. However, nicotine exposure significantly decreased lung vascularization. The current study suggests that perinatal exposure to nicotine alters lung development, an effect which may be mediated via decreased vascular endothelial growth factor (VEGF) signaling.     

New lower nicotine cigarettes can produce compensatory smoking and increased carbon monoxide exposure

Potential reduced exposure products (PREPs) are marketed as a means to reduce exposure to tobacco toxicants. Quest cigarettes, a new type of PREP, use genetically modified tobacco to provide a nicotine step-down approach, and are available as 0.6, 0.3 and 0.05 mg nicotine cigarettes. However, these cigarettes deliver equivalent levels of tar (10 mg). Prior research on low nicotine cigarettes suggests smokers will compensate for lower nicotine delivery by increasing their puffing behavior to extract more nicotine. This study tested the hypothesis that compensatory smoking will occur with this PREP as nicotine levels decrease, increasing exposure to tobacco toxins. Fifty smokers completed a within-subject human laboratory study investigating the effect of cigarette nicotine level on smoking behavior. Cigarette nicotine level was double-blinded and order of presentation counter-balanced. Breath carbon monoxide (CO) boost was used as a biomarker of smoke exposure; total puff volume to assess smoking behavior. Total puff volume was greatest for the 0.05 mg nicotine cigarette and CO boost was moderately greater after smoking the 0.3 and 0.05 mg cigarettes compared to the 0.6 mg nicotine cigarette. These data provide novel behavioral and biochemical evidence of compensatory smoking when smoking lower nicotine cigarettes. Although marketed as a PREP, increases in CO boost suggest this product can potentially be a harm-increasing product.     

Smokers deprived of cigarettes for 72 h: effect of nicotine patches on craving and withdrawal

Abstract Rationale. Research on the effects of nicotine abstinence and nicotine replacement has not provided consistent information about the impact of replacement therapies on tobacco withdrawal and craving. Objective. This study investigated craving and withdrawal symptoms over a 72-h period of abstinence from cigarettes. Methods. Twenty-four healthy volunteers, not intending to quit smoking, were housed in an experimental unit during three 72-h conditions, consisting of either free smoking, enforced smoking cessation with nicotine replacement therapy (NRT) patches, or enforced smoking cessation with placebo patches. The conditions were adhered to using a randomized crossover design, each separated by at least 10 days of washout. Patches, administered in a double-blind fashion, were given as nicotine (21 mg/24 h) and placebo every 24 h. Self-reported cigarette craving and withdrawal were assessed using multi-item scales at fixed intervals over each condition period. Urinary and plasma cortisol levels were also assayed at fixed intervals over each period. Results. Craving intensity was significantly lower with free smoke than with placebo and with NRT patches than with placebo. No difference in craving levels was found between those who smoked or those who had NRT patches. Withdrawal symptoms were significantly lower with free smoke than with either placebo or NRT patches, but there was no difference in levels of withdrawal between those on NRT patches and those on placebo. During the placebo and NRT patch periods, craving intensity displayed a circadian rhythm, with craving levels lowest in the morning and peaking in the evening. Nicotine delivered via the patch had no impact on these circadian variations in craving. There was no evidence of systematic temporal variations in craving levels during the free smoking period. Conclusions. The data suggested that craving and withdrawal symptoms may be sustained by different physiological pathways, and that only selected components of cigarette craving are influenced by NRT. Electronic Publication     

Pharmacologic and sensorimotor components of satiation in cigarette smoking

To examine mechanisms underlying satiation in cigarette smoking, 18 smokers received intravenous (i.v.) nicotine, alone or in combination with denicotinized cigarette smoke. Nicotine was administered using programmed presentations of either pulsed injections or continuous infusions, with i.v. saline serving as a control. A high-nicotine cigarette smoke condition (usual brand) was also presented. During each of the six test sessions, subjects were allowed to puff on their usual brands of cigarette ad libitum while the programmed satiation conditions were in force. Administration of i.v. nicotine caused a small suppression of ad libitum smoking behavior; denicotinized smoke produced a significantly larger reduction, showing that short-term satiation is more dependent on the presentation of smoke than delivery of nicotine per se. However, denicotinized smoke alone did not have as much effect as puffs from the usual brands of cigarettes. The combination of i.v. nicotine and denicotinized smoke puffs produced equivalent satiation to that of the usual brand. Cigarette craving and negative affect were partially relieved by iv nicotine presentations as well as by denicotinized smoke, and again the combination of i.v. nicotine and denicotinized smoke approximated the effects of the usual brand. The results of this study underscore the importance of both sensorimotor aspects of smoking and the pharmacologic effects of nicotine in tobacco dependence.     

Pembrolizumab for melanoma- safety profile and future trends

Background: Pregnant women who continue to smoke expose their developing fetus to a wide range of risks. Assisting these patients to stop smoking can be an important intervention for the health of the baby and the mother. The management of pregnant smokers can be challenging, due to the potential risks of pharmacotherapy. There are a number of options available to the clinician to aid smoking cessation in non pregnant women. These include nicotine replacement therapy (NRT), bupropion, varenicline, and a range of non-drug therapies. Objective: To provide guidance to prescribers on the best way to manage smoking cessation in the pregnant patient, reviewing the risks and efficacy of the different approaches. Methods: An extensive literature search was carried out to find original studies which examined issues surrounding the safety and efficacy of methods of smoking cessation in pregnancy. Results/conclusion: NRT is the agent of choice for smoking cessation in pregnancy as the safety of other therapies in pregnancy have not yet been proved.     

Effects of high dose transdermal nicotine replacement in cigarette smokers

RATIONALE: Nicotine replacement therapies (NRT) have been evaluated to facilitate cigarette smoking reduction in smokers unwilling or unable to quit. In most of these studies, only conventional doses of NRT have been tested and higher doses may be required to result in significant reductions in smoking and in biomarkers of exposure. OBJECTIVE: To determine if higher NRT doses in conjunction with smoking are safe and may promote significant reductions in cigarette smoking and biomarkers of exposure. METHODS: A dose-ranging, within-subject design was implemented to evaluate the effects of 15, 30 and 45 mg nicotine-patch treatment on measures of safety and the extent of smoking reduction and biomarker exposure per cigarette in smokers (N=20 completers) not immediately interested in quitting. RESULTS: Concurrent smoking and NRT were generally tolerated and resulted in no changes in blood pressure or heart rate. Slightly less than 10% of the study sample was not given the highest dose of NRT due to side effects. Self-reported cigarette smoking decreased with increasing doses of nicotine replacement and significant reductions were observed for total NNAL (a carcinogen biomarker) and carbon monoxide. However, even at the 45 mg dose, increased carbon monoxide and total NNAL per cigarette occurred, even though cotinine levels increased on average, 69.3% from baseline. CONCLUSIONS: The present results suggest that the use of high dose NRT is safe, leads to significant reductions in smoking (-49%), significant but less reductions in total NNAL (-24%) and carbon monoxide (-37%) due to compensatory smoking.     

Structural and functional alteration of blood vessels caused by cigarette smoking: an overview of molecular mechanisms

Smoking is a significant independent risk factor for cardiovascular disease and is a leading cause of structural and functional alterations of the cardiovascular system. Most clinical and experimental investigations of the pathophysiology of cigarette smoking have studied the effects of smoke as a whole, while a few studies focused on specific components of cigarette smoke, e.g. nicotine and carbon monoxide, which are only 2 of the more than 4,000 different chemicals present in cigarette smoke. The findings point to some discrepancies when the effects of whole smoke are compared to nicotine alone, while there is almost uniform agreement that both active and passive smoking have detrimental effects on the cardiovascular system, although a milder effect was suggested for the latter. This review focuses on findings from clinical and experimental studies on the vascular effects of active and passive cigarette smoking and nicotine exposure. The findings are discussed in terms of tissue (conduit vs. resistance arteries and veins), species, age, gender and dosage. Although the exact pathophysiology of cigarette smoking has not been unveiled, cigarette smoking causes injury to the vascular endothelium, produces superoxide anions, reduces production and bioavailability of nitric oxide (NO), increases production and release of endothelin, causes endothelial dysfunction, thrombosis, atherosclerosis, infarction, coronary artery disease (CAD), stroke and death.     

Sensory blockade of smoking satisfaction

Cigarette smokers were presented with controlled doses of cigarette smoke to determine whether the resulting reduction in cigarette craving depended upon perceiving the sensory qualities of the smoke. Cigarette craving was assessed before and after inhaling controlled doses of smoke in two conditions: (1) Local anesthesia of the upper and lower respiratory airways, induced by mouth rinsing, gargling and inhalation of a mist containing the topical anesthetic lidocaine; and (2) no-anesthesia control, in which all solutions were saline. A sham smoking procedure was presented in both conditions. Craving and ad lib smoking behavior were also assessed 30 minutes after controlled smoking. The results indicated that smoke, as opposed to sham puffs, significantly reduced reports of cigarette craving, and local anesthesia significantly blocked this immediate reduction in craving produced by smoke inhalation. Puffs were also rated as less desirable in the anesthesia condition. Thirty minutes after smoking, craving was no different in the anesthesia and saline control conditions. However, craving as well as smoking intake in both conditions was less when smoke had been given previously than in the sham smoking control. These results suggest that sensory cues accompanying inhalation of cigarette smoke are important determinants of immediate smoking satisfaction. However, the sustained effects of smoke intake on subsequent smoking behavior (30 min later) may be mediated by processes other than sensory stimulation of the respiratory tract, such as plasma nicotine levels.     

Mecamylamine increases nicotine preference and attenuates nicotine discrimination

Eight subjects evaluated various qualities of cigarette smoke after being given a range of doses (0, 2.5, 10 and 20 mg) of the nicotinic receptor blocker mecamylamine. In one test condition, subjects were given either high or low nicotine tobacco smoke to determine the effects of mecamylamine on their subjective responses. In another test condition, subjects were allowed to adjust the nicotine dose level of the smoke to determine the effects of mecamylamine on dose preference. When the subjects evaluated puffs of smoke with high and low nicotine content, mecamylamine caused a dose-related decrease in the self-rated strength and harshness of the high nicotine dose level smoke. In contrast, there was little effect on the low dose smoke. At the highest mecamylamine dose (20 mg) there was no significant difference in the ratings of high and low nicotine cigarettes. Low doses of mecamylamine decreased the reported desire for a cigarette, and also attenuated the reduction in desire for a cigarette caused by smoking. When the subjects were allowed to select their preferred level of nicotine intake using a smoke mixing device, the 10 and 20 mg doses of mecamylamine caused a significant increase in self-administered nicotine dose level. Despite this compensatory increase in nicotine self-administration, the reduction in desire for a cigarette after smoking was still less than after placebo.     

Dissociating nicotine and nonnicotine components of cigarette smoking

To dissociate the sensorimotor aspects of cigarette smoking from the pharmacologic effects of nicotine, smokers rated the subjective effects of nicotine-containing or denicotinized cigarettes, and intravenous (IV) nicotine or saline infusions. Three groups of participants (n=20 per group) received either: (1) continuous nicotine, (2) pulsed nicotine, or (3) saline. Each group was exposed to an IV condition once while smoking a denicotinized cigarette and once while not smoking, in a 3x2 mixed design. A fourth group (n=20) received saline while smoking their usual brand of cigarette. The dose and rate of nicotine administration were individualized based on previous measures of ad lib smoke intake. Denicotinized cigarette smoke significantly reduced craving and was rated significantly more satisfying and rewarding than the no-smoking conditions. IV nicotine reduced craving for cigarettes, and increased ratings of lightheadedness and dizziness. However, no significant satisfaction or reward was reported after IV nicotine. The combination of IV nicotine and denicotinized cigarette smoke produced effects similar to those of smoking the usual brand of cigarette. The results suggest that sensorimotor factors are critical in mediating the immediate subjective response to smoking, and that the immediate subjective effects of nicotine administered in doses obtained from cigarette smoking are subtle. Thus, addressing smokers' needs for both for the sensorimotor aspects of smoking as well as for the direct CNS effects of nicotine may be critical in enhancing smoking cessation treatment outcome.