The Neuropharmacology of Commonly Abused Drugs - Essay Example

The Neuropharmacology of Commonly Abused Drugs The Neuropharmacology of Commonly Abused Drugs Cocaine, ecstasy, heroin, and cannabis are some of the most commonly abused drugs in the world today. However, these drugs have many negative effects on the individuals consuming them, putting their health at risk. Specifically, the drugs interact with the neurochemical mechanisms of an individual’s brain in various ways. Some of the interactions result from reinforcing qualities of the drugs. In other cases, some of the drugs’ interactions with the brain arise from other effects associated with the drugs themselves. Significant amounts of research in neuropharmacology in recent years have helped improve the levels of understanding of the interactions between the abused drugs and neurochemical mechanisms in the brain (Bear, Connors, & Paradiso, 2007). As a result, research has revealed several areas of commonalities among the different drugs of abuse. While it is generally accepted that abused drugs each have specific actions in an individual’s brain, a lot of evidence has also emerged in recent years to show that their reinforcing qualities may arise from a shared ability of the drugs to interact with the reward system of the brain. The actions that to the led overall behavioural effects of a particular drug in an individual. Therefore, there is a strong connection between a drug’s neurochemical action in the brain and its behavioural effects in individuals. This paper aims at comparing and contrasting the neuro-pharmacological basis associated with using some of the commonly abused drugs such as Cocaine, Ecstasy, Heroin, and Cannabis. The paper describes how the drugs affect neurochemical activity in the brain as well as examining the various mechanisms that may underlie the characteristics that determine the potential of a drug such as, neuro-adaptive responses, the reinforcing effects, and emergency if withdrawal symptoms. Cocaine Cocaine is a naturally occurring alkaloid found in the leaves of shrub Erythroxylum coca found in South America. It is the most commonly abused stimulants. As a stimulant, Cocaine has the effect of energizing an individual thereby facilitating an increase in motor or/and psychological activity (Golan & Tashjian, 2012). The cocaine compound is extracted from shrub’s leaves before being processed into either powder, paste or freebase form. Paste is the unrefined and rudimentary form. Cocaine powder, which is the most popular form of the drug, is often consumed through nasal insufflation such as snorting. Raw leaves of the plant can also be chewed while cocaine freebase can be extracted and smoked (Golan & Tashjian, 2012). Other popular forms of cocaine include Crack and cocaine HCI. Cocaine can also be administered through injections using syringes. The impact of cocaine in terms of how it makes an individual high varies depending on the mode of administration or consumption. This also determines the rate at which the drug will get into the brain of an individual. Effects of cocaine can be grouped as psychomotor stimulant effects, autonomic functions, cardiovascular effects, convulsive properties, and local anesthetic effects (Golan & Tashjian, 2012). Psychomotor stimulant effects include euphoria, elevated mood, arousal and decreased fatigue. Autonomic functions include increased blood pressure, bronchodilation, and higher body temperatures. Consumption of cocaine can also lead to cardiovascular effects such as heart attacks. Cocaine mostly affects monoamine neurotransmitters in the brain such as dopamine, serotonin, norepinephrine, and epinephrine (Rapaka & Sadée, 2008). Similarly, cocaine also stimulates an individual’s physiological mechanisms, which are triggered in stressful situations through activation of the sympathetic nervous system. This includes an increase in blood pressure and heart rate of an individual as well as the release of hormones in the body. The euphoric and arousing effects that are associated with stimulant drugs such as cocaine can also be linked to the various behaviors and activities of individuals. Whereas cocaine and other stimulant drugs have many mechanisms of actions, their major impact is to stimulate an individual’s Central Nervous System (CNS) activity. Ecstasy Ecstasy is a synthetic psychoactive drug that shares characteristics of both hallucinogen mescaline and stimulant amphetamine. It is also known as Molly, Mandy, or by its scientific name, MDMA (methylenedioxy-methamphetamine). The drug was first synthesized in 1912 but became a popular street drug in the 1980s across Europe. It was mostly used by youths at night parties and raves due to its ability to enhance energy, sociability, endurance, and sexual arousal. Most users considered it a safe drug until it was made illegal in the US in 1985 (Lowinson, 2005). Ecstasy is often consumed or administered orally in either tablet or capsule forms and some cases an MDMA powder. MDMA or ecstasy has numerous effects on an individual in terms of affecting the individual’s behavior, as well as several neurochemical effects. For instance, consumption of the drug produces strong feelings of euphoria, increased energy, and emotional warmth as well as distorting sensory and time perceptions of an individual (Rapaka & Sadée, 2008). Small doses of ecstasy lead to serenity, relaxation, and emotional closeness in an individual. On the other hand, moderate doses can lead to intensified feelings, memory impairments, and mild hallucinogenic effects (Lowinson, 2005). However, higher doses of ecstasy can lead to hangovers, hyperthermia or heat stroke, and amphetamine-like effects. Acute effects of ecstasy include heightened perceptions, reduced appetite, stimulation and elevated mood. Furthermore, the drug has other neurochemical effects on individuals. For instance, monoamine neurotransmission, which leads to an increase in synaptic DA and 5-HT, blocks 5-HT transporters, causes Calcium-independent release of 5-HT in the neuron (Rapaka & Sadée, 2008). Other neurotoxic effects of MDMA include depletion of forebrain and potent neurotoxin. Ecstasy is also associated with long-term psychiatric problems. Heroin Heroin is another commonly abused drug, also known by various street names including H, brown, smack, horse, and tar. It is an opioid analgesic drug that was first synthesized in 1984 by C.R. Alder Wright (Glennon & Young, 2011). Heroin is mostly administered via injections and is about 2-4 times more potent than other drugs containing morphine. In some instances, Heroin is also consumed in its freebase form through smoking since it has a very low boiling point. Heroin can also be administered through sniffing or snorting. An addicted heroin user can inject themselves for up to four or five times in a day. Just like other opioids, heroin is used both as a recreational drug as well as legally as a medically prescribed drug. It is medicianal and is used as a cough suppressant, an anti-diarrhoea and analgesic drug (Lowinson, 2005). Prolonged use of heroin can lead to addiction, tolerance and physical dependence to the drug. The manner in which heroin is also administered affects its impact on an individual. An intravenous injection has the biggest impact, giving an individual the greatest intensity with a rapid onset of pleasure (usually within eight seconds) (Hollywood, 2002). However, when the drug is sniffed or smoked, the peak effects begin to manifest in about 10-15 minutes. There are two major types of opioids. The first category comprises of naturally occurring substances such as opium and soap extracted from the opium poppy. The other category comprises of semi-synthetics such as Heroin, Hydromorphone, Hydrocodone, and Oxycodone (Higgins, Silverman, & Heil, 2008). Initially, the pharmacological impact of heroin was often thought to be similar to that of the morpheme. However, recent research indicates that heroine is in fact almost ten times more potent than morpheme. As such, it gets into the brain cells faster than any other drug. Heroin has several effects on an individual, including causing increased euphoria or pleasure. The drug enhances positive feelings, reduces anxiety, and produces a sense of well-being. It also leads to analgesia by relieving pain despite the absence of impairments in other sensory modalities. Other common effects of heroin include nausea and vomiting, miosis, respiratory depression, motor effects, and cough suppression (Jenkins, 2005). Cannabis Cannabis is a psychoactive drug derived from parts of the Cannabis Sativa plant, or its subspecies cannabis indica and ruderalis. It is also commonly referred to as ganja or marijuana while in its herbal form, but known as hashish in its resinous form (Clarke & Merlin, 2013). The herbal forms of the drug are primarily derived from flowers of the female plant. Hashish is a psychoactive concentrated resin extracted from compressed buds gathered from the flowers and leaves of a mature female plant. The major chemical compound found in cannabis is Tetrahydro-Cannobinol (THC), which also has medicinal effects when consumed through ingestion or smoking. Cannabis is one of the oldest drugs in the history of man (Decorte, Potter, & Bouchard, 2011). Today, statistics indicate that about 4% of the people in the world consume cannabis in one form or another. Nevertheless, the drug is illegal in most parts of the world. The absorption rates of the drug also depend on the mode of administration. When consumed orally, the absorption rate is very slow. However, when smoked, the rate of absorption is slightly higher (von Sydow, Lieb, Pfister, Hofler, & Wittchen, 2002). While in the body, cannabis slows down the rate of metabolism in the liver. When consumed in small or moderate doses, cannabis causes relaxation, drowsiness, and memory impairment, loss of balance, reduced muscle strength, and poor coordination of motor skills such as driving (Kalant, 2001). On the other hand, if consumed in higher doses, the drug causes impaired judgment, motor impairment, paranoia, agitation, and disorganized thoughts. Comparison between the Neuropharmacology of the Drugs The commonly abused drugs such as cocaine, ecstasy, heroin, and cannabis have different effects on individuals in the emchanism they interact with the neurochemical mechanisms of their brains. For instance, cocaine mostly affects monoamine neurotransmitters in the brain such as dopamine, serotonin, norepinephrine, and epinephrine. It also stimulates an individual’s physiological mechanisms, which are triggered in stressful situations through activation of the sympathetic nervous system. On the other hand, ecstasy has different neurochemical effects in one’s brain, including monoamine neurotransmission, which leads to an increase in synaptic DA and 5-HT, blocks 5-HT transporters, causes Calcium-independent release of 5-HT in the neuron. In addition, heroin is also known for its impact in one’s brain as it gets into the brain faster than any other drug. Its main impact on the brain is causing increased euphoria or pleasure. Heroin also enhances positive feelings, reduces anxiety, and produces a sense of well-being. Conversely, Cannabis slows down the rate of metabolism in the liver. References Bear, M. F., Connors, B. W., & Paradiso, M. A. (2007). 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