Influence of tobacco smoke exposure on pharmacokinetics of ethyl alcohol in alcohol preferring and non-preferring rats

Effects of excessive alcohol drinking on nicotine biotransformation in rats

Alcohol and nicotine (tobacco smoke) are often used together, and taking both addictive substances is associated with an increased risk of certain diseases. It is extremely important to understand the pharmacodynamic and pharmacokinetic mechanisms of the interaction between nicotine and ethanol, which are still not fully understood. The study aimed to evaluate the influence of chronic alcohol consumption on nicotine biotransformation in ethanol-preferring and non-preferring male and female rats. Rats were divided into four groups depending on their alcohol preferences and gender. Nicotine, nornicotine, nicotine N-oxide, cotinine, trans-3'-hydroxycotinine, and cotinine N-oxide in rats plasma were determined by LC-MS/MS after five days of exposure to tobacco smoke. A non-compartmental analysis of nicotine and its metabolites was used for pharmacokinetic parameters calculation. Our experimental results showed that the rate of nicotine elimination depends on gender, regardless of alcohol preferences (significantly slower in females than in males). Mean residence timeof nornicotine, cotinine, and trans-3'-hydroxycotinine were significantly higher in alcohol-preferring male rats than in alcohol preferring female rats. In non-alcohol preferring female rats compared to ethanol-preferring female rats, significantly more nicotine N-oxide (fivefold) and trans-3'-hydroxycotinine (twofold) reached the general circulation unchanged. Drinking ethanol influenced the elimination of nornicotine and cotinine in male rats. Ethanol consumption was identified as a modifier of nicotine pharmacokinetics and this was gender-dependent.

The influence of tobacco smoke exposure on selected markers of oxidative stress, kidneys and liver function in the serum of rats with streptozotocin-induced diabetes

BACKGROUND

The significance of the free radicals is emphasized in the pathophysiology of diabetes and the progression of chronic diabetic complications. Smoking cigarettes increases the risk of developing type II diabetes and intensifies pathophysiological processes during the development of type I diabetes. Tobacco smoke is also additional source of free radicals. Moreover, smoking causes variety of adverse effects on organs, that have no direct contact with the tobacco smoke itself. The objective of the study was to examine the effects of tobacco smoke on the serum concentrations of relevant oxidative stress markers such as total protein (TP), reduced glutathione (GSH), glutathione S-transferase (GST) and thiobarbituric acid reactive substances (TBARS), as well as renal (creatinine, urea) and liver function (alkaline phosphatase, ALP; alanine aminotransferase, ALT; aspartate aminotransferase, AST) among animals with induced diabetes after administration of a single dose of streptozotocin (65 mg/kg, ip).

METHODS

The markers of oxidative stress and biochemical parameters were determined using spectrophotometric methods. As a biomarker of exposure to tobacco smoke, cotinine was determined using high-performance liquid chromatography with diode array detection (HPLC-DAD).

RESULTS

Tobacco smoke exposure of diabetic rats was manifested by significantly elevated liver enzymes activity - ALT (p < 0.05) and ALP (p < 0.01), higher creatinine and urea concentration (p < 0.01), lower GSH amount (p < 0.05), and higher GST activity (p < 0.05).

CONCLUSIONS

Tobacco smoking induce liver and renal damage through the mechanisms including increased oxidative stress.

Effects of Nicotine on Alcohol Drinking in Female Mice Selectively Bred for High or Low Alcohol Preference

BACKGROUND

Studies show that repeated nicotine use associates with high alcohol consumption in humans and that nicotine exposure sometimes increases alcohol consumption in animal models. However, the relative roles of genetic predisposition to high alcohol consumption, the alcohol drinking patterns, and the timing of nicotine exposure both with respect to alcohol drinking and developmental stage remain unclear. The studies here manipulated all these variables, using mice selectively bred for differences in free-choice (FC) alcohol consumption to elucidate the role of genetics and nicotine exposure in alcohol consumption behaviors.

METHODS

In Experiments 1 and 2, we assessed the effects of repeated nicotine (0, 0.5, or 1.5 mg/kg) injections immediately before binge-like (drinking-in-the-dark; Experiment 1) or during FC alcohol access (Experiment 2) on these alcohol drinking behaviors (immediately after injections and during re-exposure to alcohol access 14 days later) in adult high- (HAP2) and low-alcohol-preferring (LAP2) female mice (co-exposure model). In Experiments 3 and 4, we assessed the effects of repeated nicotine (0, 0.5, or 1.5 mg/kg) injections 14 days prior to binge-like and FC alcohol access on these alcohol drinking behaviors in adolescent HAP2 and LAP2 female mice (Experiment 3) or adult HAP2 female mice (Experiment 4).

RESULTS

In Experiment 1, we found that repeated nicotine (0.5 and 1.5 mg/kg) and alcohol co-exposure significantly increased binge-like drinking behavior in HAP2 but not LAP2 mice during the re-exposure phase after a 14-day abstinence period. In Experiment 2, 1.5 mg/kg nicotine injections significantly reduced FC alcohol intake and preference in the third hour postinjection in HAP2 but not LAP2 mice. No significant effects of nicotine treatment on binge-like or FC alcohol drinking were observed in Experiments 3 and 4.

CONCLUSIONS

These results show that the temporal parameters of nicotine and alcohol exposure, pattern of alcohol access, and genetic predisposition for alcohol preference influence nicotine's effects on alcohol consumption. These findings in selectively bred mice suggest that humans with a genetic history of alcohol use disorders may be more vulnerable to develop nicotine and alcohol co-use disorders.