What is nicotine?
Tobacco that basically comes from the plant known as nicotiana tabacum has been utilized for many years. It can be chewed, sniffed, or smoked. The initial depiction of tobacco addiction is contained in a New World report in which Spanish armed forces said that they were unable to quit smoking. Initially, nicotine was being used as an insecticide with its analogs still being used as insecticides currently (Yamamoto & Casida, 1999).
When isolation of nicotine from tobacco leaves was performed in the year 1828, scientists started researching its impacts on the body as well as brain. This research ultimately demonstrated that, even though tobacco comprises of many chemicals, the key ingredient that operates in the brain and gives addiction is nicotine. Another current research has demonstrated that the addiction given by nicotine is very powerful and is at least as strong as other drugs addictions for instance cocaine and heroin. Nicotine is a substance that is a chemical in nature, found in the leaves of tobacco. Nicotine addiction is what makes a person smoke. It is as addictive as cocaine or heroin (Oklahoma Poison Control Center, 2005).
How does nicotine work?
Mechanism of Action
Nicotine readily gets into the body. Once it is smoked, nicotine gets into the bloodstream via the lungs. When it is chewed or sniffed, nicotine goes through the nose or mouth’s mucous membranes to get into the bloodstream. Nicotine can as well get into the bloodstream via the skin. In spite of the way nicotine gets to the bloodstream, the moment it is there, it is distributed during the body as well as the brain where it stimulates specific forms of receptors referred to as cholinergic receptors (Rimrock Foundation, 2013).
Cholinergic receptors are found in a number of structures of the brain, as well as in adrenal glands, the heart, muscles, and other organs of the body. These receptors are usually activated by the neurotransmitter acetylcholine that is made in the brain, as well as by neurons in the peripheral nervous system. Acetylcholine together with its receptors participates in several activities, which include respiration, heart rate maintenance, and alertness, memory, as well as muscle movement (Rimrock Foundation, 2013).
Since the nicotine’s chemical structure is the same as that of acetylcholine, it is also has the ability to trigger cholinergic receptors. But different from acetylcholine, when nicotine gets into the brain and triggers cholinergic receptors, it can interrupt the normal performance of the brain (Rimrock Foundation, 2013). Regular use of nicotine leads to modifications in both the cholinergic receptors’ number and the acetylcholine’s and nicotine’s sensitivity of these receptors. A number of these modifications may be accountable for the tolerance development to nicotine. The moment that tolerance has developed a user of nicotine has to frequently supply the brain with nicotine, so that to preserve normal brain performance. If levels of nicotine go down, the user of nicotine will start feeling uncomfortable withdrawal signs. The inhibition of chromatin-modifying enzymes by nicotine has been shown to cause an increase in the ability of products such as cocaine to cause addiction (Volkow, 2011).
Why is nicotine a problem for health?
The most horrible health problem arising from nicotine is that it is very addictive. The majority of regular smokers would have preference not to smoke, and only keep on due to the fact that they have an addiction to nicotine (NSW Government, 2004). Tobacco smoking is responsible for the largest part of avoidable sickness as well as death in Australia. Immediate nicotine effects on the body include raised heart rate as well as blood pressure, and blood vessels’ constriction. With time, nicotine ingestion from smoking mixes with carbon monoxide to destroy the blood vessels lining and make blood platelets sticky. Together these effects lead to the heart disease development (Winstanley, Woodward, & Walker, 1995).
Even though nicotine is one of the most toxic as well as fast acting among all poisons, the smoking dose is too low to lead to acute poisoning. Nevertheless, there is a severe risk for children who take in cigarettes and care ought to be taken with cigarettes together with extinguished butts, which comprises of high concentration nicotine. Prior to developing a nicotine tolerance, the addict may go through mild nicotine toxicity effects. The nicotine in products of nicotine replacement therapy, such as the patch, lozenge, gum, inhaler or sublingual tablet is safe if utilized based on the directions of the product. The average nicotine dose from nicotine replacement therapy is between one third and one half of that acquired from smoking. Someone who is nicotine dependent is extremely not likely to go through any toxic effect from using nicotine replacement therapy.
How does the body get rid of nicotine?
Majority of nicotine is metabolized in the liver. Nicotine is as well removed in urine and filtered from the blood by the kidneys. When an individual smokes a product of tobacco, they breathe in the smoke that comprises of nicotine, as well as more than 500 chemicals.
Nicotine is the drug present in tobacco that leads to addiction. When a person has nicotine addiction, they feel like they need nicotine so that to function normally. The tobacco smoke also comprises of tar that destroys the throat, mouth, as well as lungs. Nicotine gets to the brain in 10 seconds following intake. Nicotine is a brain and the central nervous system stimulant (Rimrock Foundation, 2013). The biological half-life refers to the time taken for a material to lose half of physiologic, pharmacologic, or radiologic activity. The plasma nicotine’s half-life following cigarette smoking or intravenous infusion averages around 2 h. Nevertheless, when half-life is determined by use of the time course of excretion of nicotine through urine, which is more sensitive in detecting lower nicotine levels in the body the fatal half-life averages 11 h. The longer half-life found at lower nicotine concentrations is most likely due to slow nicotine release from body tissues (Jacob, Yu, Shulgin, & Benowitz, 1999).
Effects of Nicotine
The nicotine has been reported to have both stimulating and relaxing effects (University of British Columbia, 1997). There are various effects that are associated with nicotine consumption. These effects can be divided into immediate effects and long term effects
Immediate Effects
Some of the immediate effects that are caused by nicotine include rising in blood pressure, thickening of the blood, increased rate of heart beat, narrowing of the arteries, reduced temperatures of the skin, increased rate of respiration, vomiting, diarrhea, central nervous system stimulation
(Oklahoma Poison Control Center, 2005).
Long-term Effects
Several long-term effects are associated with the nicotine intake. These effects include high blood pressure (Sabha, et al., 2000), blood vessels blockage, and reduction of vitamin C in the body, reduced effectiveness in the manner in which immune system works, and increased cases of mouth, lungs, and throat cancers. Long-term effects of nicotine also include having upper respiratory tract cancer, cases of emphysema and/or bronchitis, stomach ulcers, loss of weight, skin dryness and presence of wrinkles on the skin, production of sperms that are not normal. There are also cases of the oral cavity cancers and gum damage leading to the loss of teeth. Smokeless tobacco is also known to result to reduction in physical performance. Smoking tobacco has been linked to more than 400 000 people in the united state every year (Oklahoma Poison Control Center, 2005).
Nicotine and Pregnancy
Smoking has resulted to a greater risk of having premature placenta detachment increasing rates of death resulting from perinatal death. This risk increases by about 20% with every half pack of cigarettes that are smoked. Women who smoke have been reported to suffer greatly from the reproductive tract infections, early menopause, menstrual and fertility disorders, as well as problems in the course of the pregnancy. There has been a rise in deaths that are related to the increase in smoking by female. It is thus estimated that more than one million female adults will die from illnesses related to tobacco. Nicotine has been indicated to have an effect on mothers who are pregnant. Smoking mothers are at a risk of low birth weight, having premature births, higher chances of having stillbirths and miscarriage. Children born by a mother who is a smoker are at a risk of having impaired mental development and impaired physical development. There may be cases of sudden infant death syndrome or SIDS with some babies being at an increased risk of being hyperactive.
Effects of Nicotine on the Brain
Research conducted recently has indicated that nicotine causes the stimulation of release of neurotransmitter known as dopamine in the pleasure circuit of the brain. The research was conducted using techniques that enable measurement of minute amounts of neurotransmitters in precise areas of the brain. The findings have shown that nicotine causes a rise in dopamine release, in the nucleus accumbens. The release of dopamine resembles the release that results from other drug of abuse like cocaine, heroin.
The beta (β) subunit of cholinergic receptor is known to have a role in addiction resulting from nicotine. Bioengineering technologies that are highly sophisticated have been employed by scientists to produce a new strain of mice that lacked the β subunit. These knockout mice were not able to self-administer nicotine. These are some of the studies that have demonstrated that β subunit of cholinergic receptor plays a crucial role in arbitrating the enjoyable effects obtained from nicotine.
Nicotine is not the only ingredient which is psychoactive in tobacco (Rimrock Foundation, 2013). Through the use of the advanced technology in brain imaging, it is now possible to see what smoking of tobacco does to the brain of a human being who is awake. Using the positron emission tomography or PET, it has been discovered that smoking of cigarette results to a dramatic decrease in the amount of essential enzymes that are involved in dopamine breakdown especially the monoamine oxidase (MOA).
Decrease in MOA leads to a rise in dopamine levels. This specific effect is not caused by the presence of nicotine but by other additional compound in cigarettes that are not known. Nicotine is, therefore, not responsible in altering levels of MAO, but affects dopamine via other mechanisms. This means that there are multiple routes through which smoking affects neurotransmitter dopamine resulting in the ultimate production of pleasure and reward feelings.
The fact that nicotine has a high level of addiction is noted when it is considered that there are a very big number of people who continue using tobacco products despite the harmful and lethal effects that are documented. There are more than 90% of smokers who have the will to quit but only 10% of those who try are successful. Although nicotine is responsible for the addiction resulting from tobacco, adverse health effects are as a result of the other chemicals in tobacco (Samet, 1992).
Withdrawal Symptoms
There are several symptoms that are associated with withdrawing from tobacco smoking. These include a drop in pulse rate and a drop in blood pressure. Withdraw also causes sleep disturbance and slower reaction. Other symptoms include tension, depression, constipation, irritability, craving for tobacco, and difficulty in concentration. Although withdraw symptoms cause discomfort for a short time, the many benefits associated with quitting smoking outweigh the harmful effects caused by nicotine (Queensland Government, 2011)
Nicotine Toxicology
The LD50 of nicotine has been determined to be 50 mg/kg and 3 mg/kg in rats and mice respectively. Between 0.5 and 1.0 mg/kg are also lethal doses in adult human (Okamoto, Kita, Okuda, Tanaka, & Nakashima, 1994). There are, however, other sources that reported human survival in higher doses (Mayer, 2013). Exposure of high nicotine concentrations onto the skin has been reported to lead to intoxication and in some cases death.
This is because nicotine is able to pass in the blood through the skin after dermal contact (Hughes, 1993). Nicotine has been regarded to be carcinogenic although no standalone study that has been conducted to confirm. Recent studied have, however, reported potential carcinogenic properties in cell culture and animal models (Hecht, 1999).
Extent of Tobacco Use
Tobacco consumption is one of the major health problems facing United States. According to a survey conducted by the National Household Survey, more than 71.2% of the people who were surveyed had used nicotine with 29.4% of them having used nicotine in the past year. About 24.2% of the people surveyed had used nicotine in the last one month. From the research, 75.5% of those ages 12 years and above who used nicotine were white, 57.4% Hispanic and 59.6% were black. Of those surveyed, 45.3%, 61.9% and 8.3% of 8th, 10th and 12th graders had smoked cigarettes.
Nicotine Addiction Treatment
The road to stop smoking is a very hard road and requires determination for one to succeed. Resources such as family members, co-workers and friends may offer the support needed to stop smoking. A smoking cessation program helps in improving the chances to succeed in smoking cessation. The other useful tool is the use of nicotine replacement therapy. This employs various products that provide reduced doses of nicotine but lacks all the other toxins found in smoke. These products include special gum, nasal sprays, and throat lozenges, among others (Dugdale, 2011).
Reference List
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