Nicotine Addiction and Role of Dopamine

Nicotine addiction is a rising concern in modern society, as it leads to many deaths across the globe, both from firsthand and secondhand smoking. Thus, it is advantageous to learn more about nicotine addiction to not only better understand it, but also to provide any real world applications to help people get over this addiction and lead healthy lives.

In a recent published paper, Nicotinic, glutamatergic and dopaminergic synaptic transmission and plasticity in the mesocorticolimbic system: Focus on nicotine effects, the researchers dug deeper in the neurological aspects of nicotine addiction. According to the paper, cigarette smoking is the leading cause of preventable deaths around the world, as about five million people prematurely die each year and only ten percent of smokers actually quit who are trying to quit (Pistillo et al.). This highlights the importance of studying nicotine addiction in the hopes of better coming up solutions or models to help individuals get over this addiction and consequently lower the number of deaths from smoking. One of the important findings in the paper includes the vital role the mesocorticolimbic system plays in nicotine addiction and the corresponding withdrawal symptoms (Pistillo et al.). In rodents, this region originates from the ventral tegmental area and controls reward seeking behavior (Pistillo et al.). The ventral tegmental area is a brain area with a high number of dopamine neurons (Koulchitsky et al.). Dopamine is important for responding to reward and is a predictor of reward, so the ventral tegmental area region plays a critical role in reward motivated behavior.

This paper is very interesting and is closely related to one of the talks in our Neuroscience Seminar class. Dr. Daniel McGehee from University of Chicago in the department of Neurobiology gave a similar talk on the research he is doing in his lab. Dr. McGehee talked about how his lab is interested in learning more at the cellular level in regards to the effects of nicotine addiction. He addressed that much is known about how different drugs stimulate the dopamine system to reinforce taking the drug, but little is known about how nicotine can cause the release of dopamine for a long period of time. Dr. McGehee and his research lab were able to discover the crucial role of nAChR and how it can induce long term potentials. This relates back to the findings in the paper in regards to the important role dopamine plays in reward motivated behavior. So, the implications of dopamine being released for a long time would be that the person will display behavior directed to getting the reward for a longer period of time. This behavior would reinforce taking the drug, causing a stronger addition. Dr. McGehee’s finding of why there was an increase in dopamine for a long duration of time after the exposure to nicotine helps to highlight the region that controls the motivating behavior associated with nicotine usage.   

Dr. McGehee and his research also helped me better understand my own research that I am doing with Dr. Stephan Steidl. Dr. Steidl through his research wants to learn more about the different pathways that activate the dopamine system, as much is already known about the effects of the dopamine system. He is interested in learning more about the inputs from the pedunculopontine tegmental nucleus (PPTg) and the laterodorsal tegmental nucleus (LDTg) to the ventral tegmental area on cue driven reward seeking behavior. We are doing experiments to show that pharmacological manipulations, which reduce cue driven reward seeking behavior, are in fact not inducing non-specific motor impairments. This will help us find the pharmacology of the receptor and the receptor sub-types that may result in drug seeking behavior. Relating this back to Dr. McGehee’s talk, he does in fact talk about his current projects and how he is looking at the LDTg and its role in activating the dopamine system. Thus, I was able to relate Dr. McGehee’s talk about LDTg to what Dr. Steidl is doing in his lab.

All in all, Dr. McGehee talk was very informative and helped make sense of nicotine addiction at the level of neurons and the role of the dopamine system. Nicotine addiction is a major concern as many individuals die from either smoking or from secondhand smoking. Thus, it is very important to learn about nicotine addiction at the neurological level in the hopes of helping individuals quit smoking who actually are trying to do so.

 

Works Cited

Addiction. Digital image. Brain Facts, n.d. Web. 2 May 2016. <http://www.brainfacts.org/~/media/Brainfacts/Article Multimedia/Diseases and Disorders/Addiction/Addiction and Circuits.ashx>.

Koulchitsky, S., C. Delairesse, T. Beeken, A. Monteforte, J. Dethier, E. Quertemont, R. Findeisen, E. Bullinger, and V. Seutin. "Activation of D2 Autoreceptors Alters Cocaine-induced Locomotion and Slows down Local Field Oscillations in the Rat Ventral Tegmental Area." National Center for Biotechnology Information. U.S. National Library of Medicine, 26 Apr. 2016. Web. 02 May 2016.

Pistillo, Francesco, Francesco Clementi, Michele Zoli, and Cecilia Gotti. "Nicotinic, Glutamatergic and Dopaminergic Synaptic Transmission and Plasticity in the Mesocorticolimbic System: Focus on Nicotine Effects." Progress in Neurobiology 124 (2015): 1-27. Web. 18 Apr. 2016.

The Reward Circuit. Digital image. N.p., n.d. Web. 3 May 2016. <http://america.pink/images/4/6/5/0/6/9/9/en/3-ventral-tegmental-area.jpg>.

The Role of LDTg. Digital image. Cell, n.d. Web. 3 May 2016. <http://www.cell.com/cms/attachment/586139/4447013/gr1.jpg>.