Increased alcohol preference and intake in nicotine-preferring rats.

Background: Alcohol and tobacco are among the leading substances that are misused together and shared genetic vulnerability is likely. Increased susceptibility to nicotine self-administration has been shown in alcohol-preferring rat-lines. However, a nicotine-preferring (nP) rat-line has not been studied for alcohol preference.

Nicotinic Cholinergic System in the Hypothalamus Modulates the Activity of the Hypothalamic Neuropeptides During the Stress Response.

Background: The hypothalamus harbors high levels of cholinergic neurons and axon terminals. Nicotinic acetylcholine receptors, which play an important role in cholinergic neurotransmission, are expressed abundantly in the hypothalamus. Accumulating evidence reveals a regulatory role for nicotine in the regulation of the stress responses.

Sex differences in nicotine preference.

Smoking is the major cause of preventable deaths worldwide, and although there is a decline in overall smoking prevalence in developed countries, the decline in women is less pronounced than in men. Women become dependent faster and experience greater difficulties in quitting. Similar trends have been observed in animal models of nicotine/tobacco addiction.

Nicotinic cholinergic and dopaminergic receptor mRNA expression in male and female rats with high or low preference for nicotine.

Background: Nicotine exerts its central actions through nicotinic acetylcholine receptors (nAChRs), which in turn regulate major neurotransmitter systems including dopamine. Nicotinic and dopaminergic systems play significant roles in physiological functions, neuropsychiatric disorders, and addiction.

Objectives: To evaluate possible differences in the expression of nAChR subunit and dopamine receptor (DR) mRNAs following voluntary nicotine intake.

Nicotine intake and problem solving strategies are modified during a cognitively demanding water maze task in rats.

Background: Nicotine is the major addictive component in tobacco, and despite well-established adverse health effects of tobacco addiction, some smokers have difficulty quitting. The acute cognitive enhancement and/or the amelioration of the cognitive disruption during withdrawal that some smokers experience after smoking are among important factors that hinder quit attempts. The animal model presented in the current study is comparable to the human smoking condition although nicotine intake routes are different.

Nicotine withdrawal in selectively bred high and low nicotine preferring rat lines.

Background: We have generated high- and low-nicotine preferring (high-NP, low-NP) rat lines using voluntary oral nicotine intake as the selection criterion. After nine generations, the estimated realized heritability for high intake was 0.26.

Bitter taste and nicotine preference: evidence for sex differences in rats.

Background: Nicotine affects sensory pathways and an interaction between taste and nicotine preference is likely. In addition to pharmacologic effects, orosensory factors are important in nicotine dependence. Recent evidence suggests a link between taste (notably bitter) receptor genes and nicotine addiction.

Nine generations of selection for high and low nicotine intake in outbred Sprague-Dawley rats.

Previous animal studies have revealed significant involvement of genetics in nicotine intake; however, the extent of the genetic contribution to this behavior has not been well addressed. We report the first study of nine generations of selection for high and low voluntary nicotine intake in outbred Sprague-Dawley rats. Bidirectional mass selection resulted in progressively greater nicotine consumption in the high nicotine-preferring line but no decrease in nicotine intake in the low nicotine-preferring line across generations.

Brain nitric oxide metabolites in rats preselected for nicotine preference and intake.

Nicotine addiction is a serious health problem resulting in millions of preventable deaths worldwide. The gas messenger molecule nitric oxide (NO) plays a critical role in addiction, and nicotine increases nitric oxide metabolites (NOx) in the brain. Understanding the factors which underlie individual differences in nicotine preference and intake is important for developing effective therapeutic strategies for smoking cessation.

The epigenetic effect of nicotine on dopamine D1 receptor expression in rat prefrontal cortex.

Nicotine is a highly addictive drug and exerts its effect partially through causing dopamine release, thereby increasing intrasynaptic dopamine levels in the brain reward systems. Dopaine D1 receptor (DRD1) mRNAs and receptors are localized in reward-related brain regions, which receive cholinergic input. The aim of this study is to evaluate whether nicotine administration affects the expression of DRD1s, and if so, whether epigenetic mechanisms, such as histone acetylation, are involved.

Oral Nicotine Self-Administration in Rodents.

Nicotine addiction is a complex process that begins with self-administration. Consequently, this process has been studied extensively using animal models. A person is usually not called "smoker" if s/he has smoked for a week or a month in a lifetime; in general, a smoker has been smoking for many years.

Region- and sex-specific changes in CART mRNA in rat hypothalamic nuclei induced by forced swim stress.

Cocaine and amphetamine regulated transcript (CART) mRNA and peptides are highly expressed in the paraventricular (PVN), dorsomedial (DMH) and arcuate (ARC) nuclei of the hypothalamus. It has been suggested that these nuclei regulate the hypothalamic-pituitary-adrenal (HPA) axis, autonomic nervous system activity, and feeding behavior. Our previous studies showed that forced swim stress augmented CART peptide expression significantly in whole hypothalamus of male rats.

Efects of hormone replacement and tamoxifen on depression in ovariectomized rats.

Objectives: To determine the effects of tamoxifen and hormone replacement therapy in order to assess their role in depressive behavior:

Material And Methods: Different protocols of hormone replacement therapies were administered to surgically ovariectomized rats. Intact rats were used for tamoxifen experiments. Properly assigned control groups were used and cognitive processes were studied on animal models of surgical menopause using the Porsolt forced swim test and locomotor activity experiments.

Forced swim stress elicits region-specific changes in CART expression in the stress axis and stress regulatory brain areas.

CART mRNA and peptides are highly expressed in the anatomical structures composing the hypothalamo-pituitary-adrenal (HPA) axis and sympatho-adrenal system. Anatomical and functional studies suggest that CART peptides may have a role in the regulation of the neuroendocrine and autonomic responses during stress. Our previous study showed that CART peptides increased significantly in the male hypothalamus and amygdala 10min after the forced swim stress.

Previous chronic exposure eliminates the conditioning effect of nicotine in rats.

Smoking continues to be a major health problem and unfortunately smoking cessation interventions have limited success; the conditioning effects of nicotine and individual differences in tobacco addiction are important factors that underlie this setback. The aim of the current study was to investigate nicotine-induced conditioned place preference (CPP) in male and female rats which were previously exposed to a free choice of oral nicotine or water and showed different preferences for nicotine; subsequently nicotine intake also varied between subjects. Exposure patterns were varied in three experiments to allow for assessing the effect of adult v.

Smoking reduces language lateralization: a dichotic listening study with control participants and schizophrenia patients.

Schizophrenia has been associated with deficits in functional brain lateralization. According to some authors, the reduction of asymmetry could even promote this psychosis. At the same time, schizophrenia is accompanied by a high prevalence of nicotine dependency compared to any other population.

Individual differences in oral nicotine intake in rats.

To study individual differences in nicotine preference and intake, male and female rats were given free access to a choice of oral nicotine (10 or 20 mg/L) or water for 24 h/day for periods of at least six weeks, starting at adolescence or adulthood. A total of 341 rats, were used in four different experiments; weight, nicotine intake and total liquid consumption were recorded weekly. Results show that rats can discriminate nicotine from water, can regulate their intake, and that there are readily detected individual differences in nicotine preference.

Tamoxifen and mifepriston modulate nicotine induced conditioned place preference in female rats.

An increasing number of studies suggest that nicotine/tobacco addiction is modulated by ovarian hormones. The levels of estrogen and progesterone appear to be important in the success of quit attempts and smoking cessation. In women smokers with the diagnosis or risk of breast cancer, the estrogen receptor modulator tamoxifen (TAM) is widely used, and even though the detrimental health effects of smoking are known, this vulnerable group has difficulty quitting and continues to smoke.

Hippocampal neuronal nitric oxide synthase (nNOS) is regulated by nicotine and stress in female but not in male rats.

NO (nitric oxide) produced in limbic brain regions has important roles in the regulation of autonomic nervous system and HPA axis activity, anxiety, fear learning, long-term memory formation, and depression. NO is synthesized from l-arginine in a reaction catalyzed by nitric oxide synthase (NOS). Neuronal nitric oxide synthase (nNOS), one of the three isoforms of NOS, is synthesized constitutively in nerve cells.

Smoking modulates language lateralization in a sex-specific way.

Smoking affects a widespread network of neuronal functions by altering the properties of acetylcholinergic transmission. Recent studies show that nicotine consumption affects ascending auditory pathways and alters auditory attention, particularly in men. Here we show that smoking affects language lateralization in a sex-specific way.

Nicotine-induced conditioned place preference in rats: sex differences and the role of mGluR5 receptors.

To elucidate sex differences in nicotine addiction and the underlying mechanisms of the conditioning aspects of nicotine, nicotine-induced conditioned place preference (CPP) was evaluated in male and female Sprague Dawley rats using a three-chambered CPP apparatus and a biased design. In a series of experiments, the dose-response curve was obtained, pairings between the drug and initially non-preferred versus preferred compartments were compared, and the involvement of mGluR5 receptors in nicotine-induced CPP was evaluated. Modulation of nicotine-induced CPP with mGluR5 inhibition was obtained by MPEP (2-methyl-6-(phenylethynyl)-pyridine hydrochloride).

Sex differences in nicotine action.

Accumulating evidence suggests that the antecedents, consequences, and mechanisms of drug abuse and dependence are not identical in males and females and that gender may be an important variable in treatment and prevention. Although there has been a decline in smoking prevalence in developed countries, females are less successful in quitting. Tobacco use is accepted to be a form of addiction, which manifests sex differences.