International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 12 Issue: 08 | Aug 2025
p-ISSN: 2395-0072
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Nicotine Addiction Pathways: Neurotransmitter Involvement and Receptor Sensitivity Kumbha Ravindra1, Arumalla Mahitha1, Tekimudi Lova kumari2 1Department of Pharmaceutical Engineering, Kakinada Institute of Technological Sciences, Ramachandrapuram 2Head of the Department, Department of Pharmaceutical Engineering, Kakinada Institute of Technological
Sciences, Ramachandrapuram. ----------------------------------------------------------------------***----------------------------------------------------------------------Abstract Nicotine addiction is a global health concern characterized by its interaction with multiple neurotransmitter systems and receptor subtypes in the central nervous system. This study reviews the biochemical pathways involved in nicotine dependence, with a focus on the roles of dopamine, serotonin, acetylcholine, glutamate, GABA, and their respective receptors, particularly the nicotinic acetylcholine receptors (nAChRs). The paper also explores genetic polymorphisms, desensitization of receptors, neuroplasticity, and behavioural sensitization contributing to addiction. The findings suggest that understanding these pathways can inform the development of novel therapeutic strategies.
Keywords Nicotine,
Addiction,
Neurotransmitters,
Receptors,
1. Introduction
Impact Factor value: 8.315
nAChRs,
Neuroplasticity
Repeated nicotine use causes long-term changes in brain function, leading to structural adaptations such as altered synaptic plasticity and gene expression. This neuroadaptation is supported by findings from epigenetic studies, which demonstrate that nicotine can alter DNA methylation patterns, histone acetylation, and microRNA regulation, ultimately influencing the expression of genes related to reward, stress, and learning. Such epigenetic modifications may help explain why some individuals develop stronger dependencies than others, even with similar levels of nicotine exposure. Furthermore, genetic predispositions, such as variations in dopamine transporter genes or CYP2A6 (a key enzyme in nicotine metabolism), can influence both the intensity of addiction and the effectiveness of cessation therapies.
In addition to dopamine, nicotine affects other neurotransmitter systems, including glutamate, GABA (gamma-aminobutyric acid), serotonin, and norepinephrine. Nicotine-induced stimulation of glutamatergic neurons enhances excitatory signals, which further promotes dopamine release. Conversely, it inhibits GABAergic inhibitory neurons, reducing the brain’s natural checks on excitatory neurotransmission. This imbalance between excitation and inhibition is crucial in the development of tolerance, craving, and withdrawal symptoms. The serotonergic system’s involvement explains why nicotine also influences mood regulation and stress response, making it appealing
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Pathway,
for individuals experiencing anxiety or depression. These multidimensional effects help explain the complex behavioral patterns of addiction, which combine physiological dependence with psychological reinforcement.[2]
Nicotine exerts its addictive effects primarily through its interaction with nicotinic acetylcholine receptors (nAChRs), which are widely distributed across the central and peripheral nervous systems. When inhaled through cigarette smoke, nicotine rapidly enters the bloodstream and crosses the blood-brain barrier within seconds, binding to these receptors in areas such as the ventral tegmental area (VTA)[1]. This interaction leads to the release of dopamine in the nucleus accumbens, a core component of the brain's mesolimbic reward pathway. Dopamine release generates pleasurable sensations, reinforcing the behavior and promoting repeated use. Over time, chronic exposure causes receptor desensitization and compensatory upregulation, making the brain dependent on nicotine for normal functioning.[7]
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Dopaminergic
Nicotine withdrawal is characterized by a range of symptoms, including irritability, anxiety, depression, impaired concentration, and intense cravings. These symptoms often appear within a few hours of the last cigarette and peak within the first few days of cessation. The neurochemical imbalance created by sudden nicotine removal leads to dysphoria and reduced cognitive function, which drives the high relapse rate seen in smokers attempting to quit. Understanding these
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