Association between contraband tobacco and illicit drug use among high school students in Canada

Increased Response to 3,4-Methylenedioxymethamphetamine (MDMA) Reward and Altered Gene Expression in Zebrafish During Short- and Long-Term Nicotine Withdrawal

An interactive effect between nicotine and 3,4-methylenedioxymethamphetamine (MDMA) has been reported but the mechanism underlying such interaction is not completely understood. This study used zebrafish to explore gene expression changes associated with altered sensitivity to the rewarding effects of MDMA following 2-week exposure to nicotine and 2-60 days of nicotine withdrawal. Reward responses to MDMA were assessed using a conditioned place preference (CPP) paradigm and gene expression was evaluated using quantitative real-time PCR of mRNA from whole brain samples from drug-treated and control adult zebrafish. Zebrafish pre-exposed for 2 weeks to nicotine showed increased conditioned place preference in response to low-dose, 0.1 mg/kg, MDMA compared to un-exposed fish at 2, 7, 30 and 60 days withdrawal. Pre-exposure to nicotine for 2 weeks induced a significant increase of c-Fos and vasopressin receptor expression but a decrease of D₃ dopaminergic and oxytocin receptor expression at 2 days of withdrawal. C-Fos mRNA increased also at 7, 30, 60 days of withdrawal. Nicotine pre-exposed zebrafish submitted to MDMA-induced CPP showed an increase in expression of p35 at day 2, α4 at day 30, vasopressin at day 7 and D₃ dopaminergic receptor at day 7, 30 and 60. These gene alterations could account for the altered sensitivity to the rewarding effects of MDMA in nicotine pre-exposed fish, suggesting that zebrafish have an altered ability to modulate behaviour as a function of reward during nicotine withdrawal.

'Both Sides of the Argument'? A critical review of existing evidence on the illicit trade in tobacco products in Canada

INTRODUCTION

The illicit trade in tobacco products (ITTP) is widely recognised as a substantial and complex problem in Canada. However, the independence of available data and quality of analyses remains unknown. Reliable and accurate data on the scale and causes of the problem are needed to inform effective policy responses.

METHODS

We searched the scholarly and grey literature using keywords related to ITTP in Canada. We identified 26 studies published in English since 2008 that present original research drawing on primary data. We analysed these studies for their independence from the tobacco industry, methodology, findings and gaps in knowledge.

RESULTS

The study finds 42% of the literature reviewed has links to the tobacco industry. These studies provide insufficient methodological detail, present higher estimates of the volume of ITTP and attribute the causes to higher rates of tobacco taxation. The classification of all indigenous tobacco sales as illicit, by both industry linked and independent studies, contributes to overestimates and serves the interests of transnational tobacco companies. There is need for independent and comprehensive data on the ITTP in Canada over time, across population groups and geographies.

CONCLUSION

While there is evidence that the ITTP in Canada is a major and complex issue that requires effective tobacco control policies, there is a limited evidence base on which to develop such responses. This review finds industry-linked studies lack independence, employ biased methodologies and serve tobacco industry interests. Independent studies present more rigorous approaches, but primarily focus on youth and the province of Ontario.

Neural and behavioural changes in male periadolescent mice after prolonged nicotine-MDMA treatment

The interaction between MDMA and Nicotine affects multiple brain centres and neurotransmitter systems (serotonin, dopamine and glutamate) involved in motor coordination and cognition. In this study, we have elucidated the effect of prolonged (10 days) MDMA, Nicotine and a combined Nicotine-MDMA treatment on motor-cognitive neural functions. In addition, we have shown the correlation between the observed behavioural change and neural structural changes induced by these treatments in BALB/c mice. We observed that MDMA (2 mg/Kg body weight; subcutaneous) induced a decline in motor function, while Nicotine (2 mg/Kg body weight; subcutaneous) improved motor function in male periadolescent mice. In combined treatment, Nicotine reduced the motor function decline observed in MDMA treatment, thus no significant change in motor function for the combined treatment versus the control. Nicotine or MDMA treatment reduced memory function and altered hippocampal structure. Similarly, a combined Nicotine-MDMA treatment reduced memory function when compared with the control. Ultimately, the metabolic and structural changes in these neural systems were seen to vary for the various forms of treatment. It is noteworthy to mention that a combined treatment increased the rate of lipid peroxidation in brain tissue.