Journal of Caffeine and Adenosine Research最新文献

Background: The majority of college students report caffeine use with many using caffeine daily. Energy drink (ED) use, in particular, is common among college students, and numerous studies link these heavily caffeinated drinks to a variety of adverse consequences including substance use and risky behaviors. However, little is known about correlations between any-source caffeine use and other substance use and problems. The purpose of this study was to evaluate patterns of caffeine use and examine the relationships between caffeine, in general, and EDs specifically, and adverse health behaviors in college students. Methods: We used data from a longitudinal study of alcohol use and health-related outcomes to assess caffeine, alcohol, nonprescription drug, and tobacco use and symptoms of alcohol dependence in 1958 freshmen from a mid-Atlantic university during Fall 2012. We compared adverse health behaviors between caffeine users and nonusers and ED users and nonusers. Data were evaluated separately in men and women. Results: While women reported significantly more caffeine use than men, men reported more ED use. EDs, regardless of frequency of use, were associated with all adverse health behaviors, but only in female students. Similarly, daily any-source caffeine use was significantly associated with alcohol, nonprescription drug, and tobacco use in female students, but in men, the association was less robust. Conclusions: This research shows that caffeine use is prevalent among college students, and, in female students, is associated with alcohol, nonprescription drug, and tobacco use and alcohol dependence symptoms. Interventions aimed at promoting healthy behaviors may be especially useful in this population.

Background: Adenosine kinase (ADK) is a key regulator of hepatic metabolism. Its deficiency in the liver causes hepatic steatosis and methylation defects. In this study, we investigated whether reduced ADK expression affects the susceptibility of the liver to a carcinogen. Methods: We investigated ADK expression in samples from 11 liver cancer patients. We used transgenic Adk-tg mice with reduced hepatic ADK to study their susceptibility to a carcinogen. We exposed 45 Adk-tg and 21 wild-type (WT) mice to the carcinogen diethylnitrosamine (DEN) and the tumor promoter phenobarbital (PB) and examined the survival and body weight. Results: Seven of 11 patients with liver cancer had reduced ADK expression. A Kaplan-Meier survival curve showed a significantly increased mortality rate of DEN/PB-exposed Adk-tg mice compared with WT mice. Conclusions: Reduced hepatic ADK increases the susceptibility to the acute toxic effects of a carcinogen. Low hepatic ADK might be a risk factor and biomarker for cancer development.

Recent studies on interactions between striatal adenosine and dopamine and one of its main targets, the adenosine A_2A receptor-dopamine D₂ receptor (A2AR-D2R) heteromer, have provided a better understanding of the mechanisms involved in the psychostimulant effects of caffeine and have brought forward new data on the mechanisms of operation of classical orthosteric ligands within G protein-coupled receptor heteromers. The striatal A2AR-D2R heteromer has a tetrameric structure and forms part of a signaling complex that includes a Gs and a Gi protein and the effector adenyl cyclase (subtype AC5). Another target of caffeine, the adenosine A₁ receptor-dopamine D₁ receptor (A1R-D1R) heteromer, seems to have a very similar structure. Initially suggested to be localized in the striatum, the A1R-D1R heteromer has now been identified in the spinal motoneuron and shown to mediate the spinally generated caffeine-induced locomotion. In this study, we review the recently discovered properties of A2AR-D2R and A1R-D1R heteromers. Our studies demonstrate that these complexes are a necessary condition to sustain the canonical antagonistic interaction between a Gs-coupled receptor (A2AR or D1R) and a Gi-coupled receptor (D2R or A1R) at the adenylyl cyclase level, which constitutes a new concept in the field of G protein-coupled receptor physiology and pharmacology. A2AR antagonists targeting the striatal A2AR-D2R heteromer are already being considered as therapeutic agents in Parkinson's disease. In this study, we review the preclinical evidence that indicates that caffeine and A2AR antagonists could be used to treat the motivational symptoms of depression and attention-deficit/hyperactivity disorder, while A1R antagonists selectively targeting the spinal A1R-D1R heteromer could be used in the recovery of spinal cord injury.

Background: Alcohol mixed with energy drink (AmED) use among college students is associated with specific adverse effects (e.g., sexual assault, driving while intoxicated). This study offered the opportunity to evaluate correlates of past year AmED use in a large sample of college students. Methods: In autumn 2010, emails were sent to all first year students (n = 29,536) at 11 colleges and universities in North Carolina and Virginia, inviting them to participate in a brief web-based survey to be used to establish a cohort for the parent tobacco use study; 10,340 (35%) students responded to the web-based survey, which elicited items on demographics, past year use of AmED, and other health behaviors. Results: Past year of AmED was reported by 29.4% of students. Logistic regression analysis revealed that female gender (adjusted odds ratios [AOR] = 1.28, 95% confidence interval [CI] = 1.16-1.42); ever use of smokeless tobacco (AOR = 3.51, 95% CI = 3.00-4.10); current smoking (AOR = 4.97, 95% CI = 4.34-5.69); 2 or fewer days of physical activity per week (AOR = 1.16, 95% CI = 1.04-1.28); and 7 or 8 hours of sleep per day (AOR = 1.12, 95% CI = 1.02-1.24) predicted risk of past year use of AmED. Conclusions: Nearly a third of first year college students reported past year use of AmED. Our finding of increased past year use of AmED use among women is new and might reflect the changing epidemiology of female college alcohol use. Of additional concern, such use might also reflect targeted marketing to women by the energy drink industry. Findings can guide future research as well as substance counseling to college students.