Cocaine: history, use, abuse.

 

cocaine articles

Sep 02,  · Aug. 20, — Spending on cannabis, cocaine, heroin and methamphetamine fluctuated between $ billion and $ billion each year from to , rivaling what Americans spend each year on. Jan 15,  · Cocaine is a white powder. It can be snorted up the nose or mixed with water and injected with a needle. Cocaine can also be made into small white rocks, called crack. Crack is smoked in a small glass pipe. Cocaine speeds up your whole body. You may feel full of energy, happy, and excited. But then your mood can change. Aug 27,  · Cocaine is a highly addictive drug that ups your levels of alertness, attention, and energy. You may hear it called a stimulant. It’s made from the coca plant, which is native to South America.


Cocaine and Crack Cocaine - The New York Times


An initial, short-term effect—a buildup of the neurochemical dopamine—gives rise to euphoria and a desire to take the drug again. Further pursuit of this and similar leads are first steps toward a complete understanding of the transition from cocaine abuse to addiction—and, ultimately, more effective treatments for those who are addicted. Some 20 years ago, scientists identified the specific brain mechanisms that underlie the cocaine high.

Since then, neurobiologists have focused on the followup questions: What does chronic cocaine abuse do cocaine articles the brain to cause addiction? In clinical terms, how does repeated cocaine exposure make individuals compulsively continue to take the drug even when they know it may cost them their jobs, possessions, loved ones, freedom, cocaine articles, and even their lives? Why do people with every reason and intention to quit for cocaine articles find it so hard to get away from the drug, cocaine articles, and why do they remain vulnerable to relapse after years of abstinence?

We do not yet have complete cocaine articles to these questions, but we have learned a great deal. We now know that cocaine affects brain cells in a variety of ways.

Some of its effects revert quickly to normal. Others cocaine articles for weeks after the drug leaves the brain. With repeated exposure to cocaine, these short- and intermediate-term effects cumulatively give rise to further effects that last for months or years and may be irreversible.

This article presents in broad outline the emerging picture of the neurobiology of cocaine addiction, cocaine articles. Finally, the article discusses how investigations into the neurobiology of cocaine abuse are providing clues to cocaine vulnerability and the clinical implications of that research, cocaine articles. Snorted, smoked, or injected, cocaine rapidly enters the bloodstream and penetrates the brain.

The drug achieves its main immediate psychological effect—the high—by causing a buildup of the neurochemical dopamine. Dopamine acts as a pacesetter for many nerve cells throughout the brain. At every moment of our lives, dopamine is responsible for keeping those cells operating at the appropriate levels of activity to accomplish our needs and aims. Whenever we need to mobilize our muscles or mind to work harder or faster, dopamine drives some of the involved brain cells to step up to the challenge.

Dopamine originates in a set of brain cells, cocaine articles, called dopaminergic dopamine-making cells, that manufacture dopamine molecules and launch them into their surroundings. Some of the free-floating dopamine molecules latch onto receptor proteins on neighboring receiving cells.

The more dopamine molecules come into contact with receptors, the more the electrical properties of the receiving cells are altered. To keep the receiving cells in each brain region functioning at appropriate intensities for current demands—neither too high nor too low—the dopaminergic cells continually increase and decrease the number of dopamine molecules they launch. They further regulate the amount of dopamine available to stimulate the receptors by pulling some previously released dopamine molecules back into themselves.

Cocaine interferes with this latter cocaine articles mechanism: It ties up the dopamine transporter, a protein cocaine articles the dopaminergic cells use to retrieve dopamine molecules from their surroundings. As a result, with cocaine on board, dopamine molecules that otherwise would be cocaine articles up remain in action, cocaine articles. Dopamine builds up and overactivates the receiving cells.

Although cocaine also inhibits the transporters for other neurotransmitter chemicals norepinephrine and serotoninits actions on the dopamine system are generally thought to be most important. Early rudiments are found in worms and flies, which take us back 2 billion years in evolution. Thus, cocaine articles, cocaine alters a neural circuit in the brain that is of fundamental importance to survival.

Such alterations affect the individual in profound ways that scientists are still trying to understand, cocaine articles. Cocaine produces dopamine buildup wherever the brain has dopamine transporters. However, its ability to produce pleasure and euphoria, loss of control, and compulsive responses to cocaine articles cues cocaine articles all be traced to its impact on the set of interconnected regions in the front part of the brain that make up the limbic system Hyman and Malenka, ; Kalivas and McFarland, ; Koob, Sanna, and Bloom, ; Nestler, Dopamine-responsive cells are highly concentrated in this system, which controls emotional responses and links them with memories.

One particular part of the limbic system, the nucleus accumbens NAcseems to be the cocaine articles important site of the cocaine high. Cocaine articles stimulated by dopamine, cells in the NAc produce feelings of pleasure and satisfaction. The natural function of this response is to help keep us focused on activities that promote the basic biological goals of survival and reproduction.

When a thirsty person drinks or someone has an orgasm, for example, dopaminergic cells flood the NAc with dopamine molecules. By artificially causing a buildup of cocaine articles in the NAc, as described above, cocaine yields enormously powerful feelings cocaine articles pleasure.

The amount of dopamine connecting to receptors in the NAc after a dose of cocaine can exceed the amounts cocaine articles with natural activities, cocaine articles, producing pleasure greater than that which follows thirst-quenching or sex. In fact, cocaine articles, some laboratory animals, if given a choice, will ignore food and keep taking cocaine until they starve.

The limbic system also includes important memory centers, located in regions called cocaine articles hippocampus and amygdala. These memory centers help us remember what we did that led to the pleasures associated with dopamine release in the NAc—for example, where we found water and how we attracted a mate. When someone experiences a cocaine high, these regions imprint memories of the intense pleasure as well as the people, places, and things associated with the drug, cocaine articles.

From then on, cocaine articles, returning to a place where one has taken cocaine or merely seeing images of cocaine-related paraphernalia triggers emotionally loaded memories and desire to repeat the experience. Scientists believe that repeated cocaine exposure, with its associated dopamine jolts, alters these cells in ways that eventually convert conscious memory and desire into a near-compulsion to respond to cues by seeking and taking the drug.

A third limbic region, the frontal cortex, cocaine articles where the brain cocaine articles information and weighs different courses of action. The frontal cortex acts as a brake on the other regions of the limbic system when we decide to forgo a pleasure in order to avoid its negative consequences. Activity here can help a nonaddicted person heed the disastrous prognosis of continued cocaine abuse and suppress drug-taking urges emanating from the NAc, hippocampus, and amygdala.

Once someone becomes addicted, however, the frontal cortex becomes cocaine articles and less likely to prevail over the urges Nestler and Malenka, cocaine articles, ; Volkow, cocaine articles, Fowler, and Wang, Cocaine causes many types of intermediate-term alterations in cocaine articles cell functioning.

Cocaine articles example, exposure to the drug can alter the amounts of dopamine transporters or dopamine receptors present on the surface of nerve cells, cocaine articles. The changes involving genes, however, are particularly intriguing, cocaine articles.

They occur in the limbic system, the primary site for cocaine effects, and are sufficiently fundamental and long-lasting to contribute significantly cocaine articles the transition from drug abuse to addiction. Genes determine the shape and function of every cell, cocaine articles. Every individual is born with a unique combination of roughly 30, genes.

Every cell in the body contains all 30, One cell differs from another—a liver cell looks and acts differently from a brain cell, for example—because, in each, certain genes are turned on, while others are turned off, cocaine articles. The popular notion that our genes never change is incorrect. It is true that the fundamental pattern of gene activation that gives each of our cells its essential properties is fixed once and for all during development.

For example, once a cell develops into a liver cell, it remains a liver cell for life and cannot be converted into a brain cell, cocaine articles. However, every cell retains the capacity to change the level of activity expression of a portion of its genes in response to the demands we place upon it. An example is weightlifting: Muscle cells respond to repeated exercise by increasing the expression of certain genes, leading to growth and strengthening of the individual cells and, cocaine articles, collectively, of the cocaine articles muscle.

So it is with brain cells: As we use them, they respond with changes in gene expression that, overall, increase their capacity to meet the demands we make upon them.

For example, our brains register and store memories by altering gene expression in cells in the hippocampus and amygdala, cocaine articles. Chemicals that act this way are called genetic transcription factors, cocaine articles. Main panel Cocaine causes the neurotransmitter dopamine to build up at the interface between VTA cocaine articles and NAc cells, cocaine articles, triggering pleasurable feelings and NAc cellular activities that sensitize the brain to future exposures to the drug.

Molecular biology gave us the tools to accomplish this. The extreme persistence of those features of addiction indicates that cocaine must cause some equally long-lasting neuro-biological effects. Scientists have identified one potentially key type of cocaine-related change that appears to last for many months after the last cocaine exposure, and perhaps longer: an alteration in the physical structure of nerve cells in the NAc.

Chronic cocaine exposure causes these cells to extend and sprout new offshoots on their dendrites Nestler, ; Robinson and Berridge, cocaine articles, Dendrites are the branch-like fibers that grow out from nerve cell bodies and collect incoming signals from other nerve cells.

Just as a bigger antenna picks up more radio waves, more dendrite branches in the NAc theoretically will collect a greater volume of nerve signals coming from other regions—for example, the hippocampus, amygdala, and frontal cortex. This will give those other cocaine articles an enhanced influence over the NAc, which could drive some of the very long-lived behavioral changes associated with addiction. For example, enhanced inputs from the hippocampus and amygdala could be responsible for the intense craving that occurs when drug-associated memories cocaine articles stimulated e.

When laboratory animals are treated with a compound that cocaine articles CDK5 in the NAc and then are given cocaine, the nerve cell growth normally associated with exposure to the drug does not cocaine articles. What makes certain individuals particularly vulnerable to addiction and others relatively resistant? This degree of heritability exceeds that of many other conditions that are considered highly heritable, such as type 2 non-insulin-dependent diabetes, hypertension, and breast cancer.

The specific genes that confer risk for cocaine addiction remain unknown. One possibility is that at least some of them are the same genes that are affected by cocaine exposure.

It is also possible that other genes—genes not affected by cocaine exposure—are responsible. Work is now under way to examine these alternatives. Finding addiction vulnerability genes will enable us to identify individuals cocaine articles are at particular risk for an addictive disorder and target them for educational and other preventive measures.

It will also help us understand how factors other than genetics contribute to the development of addiction. The identification of underlying biological mechanisms has been crucial for all major advances in treatment of other medical cocaine articles, and there is no reason to think addiction will be any different.

NAc nerve cells make five types of dopamine receptors; drugs that affect the functioning of one or more of them could, in theory, produce a palliative effect on cocaine addiction. Efforts are under way in each of these areas, including clinical trials, but so far no clear breakthrough has been reported.

A medication aimed at preventing or reversing such changes might be an effective approach for treating cocaine addiction. There are literally hundreds of proteins that could be targeted in development of such a medication. The same is true for numerous additional molecular changes that have been implicated in cocaine addiction. Effective medications for treating cocaine addiction will eventually be developed, and the best strategy for progress in this area is to target neurobio-logical mechanisms, such as those described cocaine articles. Although the process takes a very long time—it can take 10 to 20 years to advance from identification of a disease mechanism to development of a new treatment—this work is in progress and represents the best hope for those who are addicted.

People often ask: Is it possible to treat a drug addiction with another drug? Even though psychological and social factors predominate in the presentation and diagnosis of addiction, the disease is at its core biological: changes that a physical substance drug causes in vulnerable body tissue brain, cocaine articles. He or she must then work against powerful biological forces to recover from addiction; those cocaine articles succeed often do so only after many attempts, and many do not succeed.

Presumably, cocaine articles, effective psychosocial treatments for addiction work by causing changes in the brain, perhaps even some of the same changes that will be produced by effective medications.

While very little information is currently available on the neurobiological mechanisms underlying psychosocial treatments, this is a topic of great interest. The most important goal for the next decade is to translate the knowledge we have already gained, along with any future advances we cocaine articles, into better treatments for addiction. National Center for Biotechnology InformationU. Journal List Sci Pract Perspect v.

 

The Neurobiology of Cocaine Addiction

 

cocaine articles

 

Sep 02,  · Aug. 20, — Spending on cannabis, cocaine, heroin and methamphetamine fluctuated between $ billion and $ billion each year from to , rivaling what Americans spend each year on. Cocaine is a powerfully addictive stimulant drug made from the leaves of the coca plant native to South America. Although health care providers can use it for valid medical purposes, such as local anesthesia for some surgeries, recreational cocaine use is illegal. Cocaine interferes with this latter control mechanism: It ties up the dopamine transporter, a protein that the dopaminergic cells use to retrieve dopamine molecules from their surroundings. As a result, with cocaine on board, dopamine molecules that otherwise would be picked up remain in redirixss.tk by: