Nicotine itself is not addictive, but it is responsible for releasing dopamine, a neurotransmitter associated with pleasure, and boosters in the brain, thus inducing addictive tendencies in humans. Nicotine is a chemical found in tobacco leaf, the main ingredient in cigarettes, and is said to cause addiction and illness in cigarette smokers (World Health Organization (WHO)).
Nicotine mimics the activities of acetylcholine, a natural neurotransmitter in the central nervous system and the nerve-muscle junction of skeletal muscles. Acetylcholine is responsible for excitability, which causes increased heart rate, alertness, and reaction times (Psychopharmacology (Berl). 1989; 97 (2): 257-61.). Because acetylcholine and nicotine are chemically similar, they activate the same cholinergic receptors in the brain. Nicotine-acetylcholine receptors consist of nerve endings that release dopamine when they combine or bind with nicotine or acetylcholine. Receptors are like cups that have the exact dimensions to fit a neurotransmitter molecule, such as acetylcholine.
The cup itself is lined with nerve endings (neuron tips). It is these nerve endings that release dopamine when the neurotransmitter acetylcholine binds to cup-shaped acetylcholine receptors (cholinergic receptors). A dopamine booster and reward phenomenon develops because the dopamine released from nerve endings initiates a sensation of pleasure in the brain of the individual. The reinforcement mechanism starts when the brain becomes addicted to the pleasure caused by dopamine that is released from cholinergic receptors. This means that the brain constantly seeks to be pleased. So what will happen in the case of cigarette smokers is that they will continue to smoke cigarettes so that the nicotine in the cigarette can induce the release of dopamine in the brain, making them feel happy every time they E cigarette smoke a cigarette (Nature Reviews). Neuroscience 7, 967-975 (December 2006)).
When cigarette smokers first smoked cigarettes, there were only a few cholinergic receptors available because the natural action of acetylcholine only needs the normal number of receptors provided by nature to do its job. However, increasing the concentration of available nicotine rendered normal amounts of cholinergic receptors insensitive to the presence of increased numbers of nicotine at cholinergic receptors. This desensitization causes the production or growth and development of more cholinergic receptors. These additional cholinergic receptors will soon be desensitized from excess available nicotine. Such processes occur until equilibrium is reached. The balance is reached when cigarette smokers decide how many cigarettes they will consume or smoke on any given day. At this time, there will be a fixed number of receptors available for the addiction to continue. Smokers will typically say that they smoke one or two packs per day. They said this because of the number of receivers available to accommodate two packs of cigarettes in one day.
One detrimental effect of all this is the fact that such large amounts of cholinergic receptors are now available and starved for nicotine. Therefore, they can stimulate dopamine to please the cigarette smoker. This is why cigarette smokers have a hard time quitting. Therefore, the best approach a cigarette smoker can use to quit smoking is to gradually reduce the number of cigarettes smoked in a given time interval.
In addition to the dopamine-inducing effect of nicotine, nicotine speeds up your heart rate every time you smoke a cigarette. From a medical perspective, having a constant artificial increase in heart rate isn’t a great idea either. For one thing, a steady increase in heart rate from medications like nicotine can cause heart disease, (WHO). According to the World Health Organization, tobacco use causes diseases that affect the heart and lungs, such as heart attacks, strokes, chronic obstructive pulmonary disease (COPD), emphysema, and cancer. Most cigarette-induced cancers are lung cancer, cancers of the larynx, mouth, and pancreas. Cigarette smoke also causes heart attacks, peripheral vascular disease, and hypertension. The World Health Organization estimates that tobacco is responsible for around 5.4 million deaths in 2004 and around 100 million deaths during the 20th century.
In addition to its addictive effects on the central nervous system, cigarette smoke contains a multitude of carcinogens. They work by binding to DNA causing many genetic mutations. Nicotine could be the main culprit for DNA binding that causes genetic mutations, leading to cancer. Nicotine is said to disrupt the natural processes of apoptosis (programmed cell death) by binding to DNA in cells (National Institute of Health (NIH)). Defective cells consist of junk DNA and other waste materials. When apoptosis is inhibited,