Nicotine Research Paper

Introduction

Nicotine

Nicotine illustrates one of the most popular addictive substances in the world. Since the early colonization of the united states, nicotine has increased in popularity with the first source originating from tobacco. Unfortunately, undesired health effects are present with tobacco use as a result of additives present in the smoke such as cyanide, benzene, formaldehyde, methanol, acetylene, and ammonia. The health effects of tobacco were publicized in the 1960s with large campaigns launching to spread awareness over the risks associated with its use; however, this attempt did not prove incredibly successful as a result of the nicotine dependence that developed with continued cigarette use.

In recent years, popularity of tobacco has increased with the use of waterpipes, more commonly known as hookah. The health risks associated with this form of smoking are similar to cigarettes as hookah pipes are linked to lung cancer and various other respiratory and heart diseases. The hookah apparatus heats charcoal, which indirectly heats the tobacco. The smoke filters through water at the bottom of the hookah pipe and draws up through a hose to the mouthpiece. Flavors are now added

to the tobacco leaves, such as chocolate, coffee, cola, and lemon in an attempt to provide a more pleasurable experience for the user. A previous analysis reveals significant amounts of nicotine, tar, and heavy metals in the smoke from the waterpipe. The hookah may increase the exposure of a smoker to harmful substances because one session of hookah generally lasts approximately 40 minutes, unlike the cigarette, which only provides a session lasting between 5 and 10 minutes. This method is gaining popularity particularly in the younger generation with hookah bars and cafes rising in prevalence.
Electronic cigarettes and hookahs are two options now available to smokers that provide nicotine without the smoke. A battery works to power the heating element that activates the cartridge holding nicotine and other flavorings and liquids. The use of e-cigarettes still provides the user with nicotine dependence and, therefore, withdrawal symptoms such as irritability, depression, and anxiety. Even though e-cigarettes are considered less harmful, long-term risks and secondhand exposure effects are still largely unknown.
When nicotine is inhaled, it passes through the lungs and into the bloodstream. Once in the bloodstream, it moves through the body and brain where cholinergic receptors are activated. Cholinergic receptors are located in the muscles, heart, and adrenal glands and are generally activated by the neurotransmitter acetylcholine. Nicotine has a similar chemical structure to acetylcholine and as a result, works as an agonist to activate the cholinergic receptors. Continuous use of nicotine changes the number of these receptors and the sensitivity of the receptors to both structures. This causes a tolerance to be built which gives the user feelings of withdrawal, which often leads the user to increase the amount of nicotine they ingest. Nicotine works in a similar way to other drugs such as cocaine or heroin by increasing the dopamine levels in the brain (stimulates the release of dopamine). This mechanism gives the euphoric feelings users associate with the drug. As a result of nicotine dependence, fewer than 10 % of users that attempt to quit smoking are successful.

Cocaine/Drug Substitute

A number of drug substitutes exist that are work similarly to cocaine. Caffeine, not commonly thought of as a drug, works as a stimulant. Its side effects include restlessness, excitability, dizziness, anxiety, irritability, dehydration, increased body temperature, rapid breathing and heart rate, headache, lack of concentration, and stomach pains. Overdosing on caffeine has the ability to cause seizures, panic attacks, and vomiting. While it is rare, people can die from caffeine overdose. Serious long-term effects can also result from continued use such as infertility, osteoporosis, ulcers, depression, and, as with other drugs, dependence. Caffeine taken with other drugs can have cause major cardiovascular and neurological difficulties. Caffeine increases glucose utilization in the nucleus accumbens which is the structure correlating to reward, motivation, and addiction). It also releases dopamine in the prefrontal cortex leading to reinforcement.

Epigenetics

Epigenetic inheritance discredits the idea that inheritance only occurs as a result of the passing of DNA from parent to offspring. What a parent does may affect the future generation through epigenetic tags. It can be difficult to prove an epigenetic change as a researcher must disprove the possibility of genetic mutations and also the possibility that direct exposure of a substance may have affected a change in the health of the individual. Evolutionarily, epigenetics have given another consideration to genome changes. Where a change in the genome happens slowly, an epigenomic change can happen rapidly in response to environmental factors.
A study at the Mount Sinai Medical Center found that regulating a single, specific gene in the brain region related to drug addiction can reduce drug and stress responses. This study focused on transcription factors and epigenetic modifications that were altered by exposure to drugs and stress and how these alterations controlled gene expression. Another study by Vassoler et al. found that drug availability and environmental factors are major aspects of addiction. It was found that cocaine self-administration followed by forced withdrawal increases mRNA and protein levels in the rat prefrontal cortex. In addition, they observed increased acetylation of histones associated with BDNF promoters in the sperm of sires that were administered cocaine. This shows an epigenetic mechanism that reveals transmission of cocaine-related transmission from progenitors to descendants. The epigenetic process is largely coordinated through chromatin structure. Changes in chromatin structure mediate heritable epigenetic occurrences and also changes that occur in mature neurons. Modifications of histones include acetylation, phosphorylation, and methylation and these modifications regulate chromatin structure.

Caenorhabditis Elegans

Caenorhabditis Elegans functions as a model organism for research in developmental biology and neurology as it is a small, transparent nematode that can be easily and cheaply housed and cultivated in large numbers. In addition, hermaphrodites (females) are the most prevalent gender which allows for consistency in studies. They can self fertilize as well as reproduce with males. Their short life span of approximately 2 to 3 weeks aids in the reduction of the experimental cycle time and thus facilitates biological study. C. elegans also have a constant 959 cells with an unchanging position and transparency which yields a great tool for study of genes and cell fate. In its life cycle, C. elegans begins as an egg and within eight hours, it enters the L1 stage, followed by the L2, L3, L4, and then adult stages. Instead of going into the L3 stage, the worm may enter a dauer stage if it experiences harsh living factors that prevent development.
The genome of the organism is larger than E. coli and 1/30 the size of the human genome and completely sequenced. Interestingly, the genome is surprisingly similar to to humans (40 % homologous). As a result, C. elegans is an ideal organism in studying human diseases and epigenetics. Due to the simplicity and size of C. elegans and its genomic characteristics, it is a model experimental organism for biological study.

Histone Isolation and Western Blot

Histone proteins are major protein components of chromatin, which the genome is composed of in eukaryotic cells.

Once histones are modified, the identification of these marks on histones is necessary to understand the relationship between environmental factors and epigenetic changes. Different chemical techniques are used for the purification and separation of histone proteins. To quantify the relative change in a histone modification, it is necessary to measure bands from the blot with the antibody of interest and the control proteins. This utilizes the western blot method, which involves separation by size, transfer to a solid support, and marking target proteins using primary and secondary antibodies. The proteins are separated by molecular weight by gel

electrophoresis.