altered mRNa Levels of Stress-Related Peptides in Mouse hippocampus and Caudate-Putamen in Withdrawal after Long-Term Intermittent Exposure to Tobacco Smoke or Electronic Cigarette Vapour.

Introduction:
This article presents a study on the effects of long-term withdrawal from tobacco smoke and e-cigarette vapour on behavior and gene expression in mice. The study aimed to investigate the molecular correlates underlying the neurobiological mechanisms of the behavioral alterations observed at late time-points of withdrawal.

Key Points:

* Mice were exposed to intermittent cigarette smoke, e-cigarette vapours or an e-cigarette vehicle for three 30-min sessions/day for seven weeks.
* Mice were tested for affective and cognitive correlates of withdrawal 60 days after the last treatment or air exposure.
* Withdrawal from both tobacco smoke and e-cigarette vapours affected the mRNa levels of Crf and Crf1 in the hippocampus.
* The mRNa levels for Crf2 were analyzed in both brain regions, and no statistically significant alterations were detected.
* The mRNa levels of Pnoc were reduced by withdrawal in the CPu, while the nociceptin receptor Nop levels were not affected in any brain region.
* The Penk mRNa levels were not affected by nicotine withdrawal in hippocampus or CPu, but the corresponding opioid receptor Dop showed a significant reduction in the hippocampus.
* The Dop levels doubled in the CPu of mice that had been exposed to e-cigarettes, with no effect exerted by exposure to cigarette smoke.

Main Message:
The study demonstrates that long-term withdrawal symptoms belonging to both the affective and cognitive domains can be reproduced in mouse models of both cigarette smoking and e-cigarette vaping. The observed long-term behavioral alterations are associated with lasting molecular alterations in peptidergic signalling, particularly in the hippocampal and striatal circuitry. The findings suggest that e-cigarette use is able to provoke long-term alterations in brain signalling that are comparable to those of cigarette smoke, indicating that the investigation of neurobiological correlates of e-cigarette vaping deserves further research efforts.

Carboni L, Ponzoni L, Braida D, Sala M, Gotti C, Zoli M. altered mRNa Levels of Stress-Related Peptides in Mouse hippocampus and Caudate-Putamen in Withdrawal after Long-Term Intermittent Exposure to Tobacco Smoke or Electronic Cigarette Vapour. International journal of molecular sciences. 2021;22(2). doi:10.3390/ijms22020599