26 May 2008

Pills for the mind


For thousands of years, people have been trying to find substances that they hoped would increase their mental abilities and endurance. Trying to increase their intelligence, people chewed, boiled or smoked special leaves, roots and fruits. These searches continue today – the only difference is that now shamans work not in forests, but in pharmaceutical laboratories. If you ask what motivates them, shamans will answer that they are trying to invent medicines for the effects of Alzheimer's disease, distracted attention syndrome, strokes, dementia provoked by Parkinson's disease and schizophrenia. Actually, it's true. But by creating drugs that help the sick, scientists at the same time offer means to smarten up healthy people.

These drugs are commonly called "cognition enhancers" – means that stimulate cognitive abilities. They affect – usually by changing the ratio of neurotransmitter chemicals - the activity of the nervous system, which is behind such mental operations and processes as concentration, perception, learning, memorization, language proficiency, planning and decision-making. This week, a report was published by the British scientific society "Academy of Medical Sciences" ("Brain science, addiction and drugs". The Academy of Medical Sciences, 10 Carlton House Terrace, London SW1Y 5AH), which states that in the next few decades, a large number of similar drugs affecting the brain will surely appear. Sir Gabriel Horn, a scientist at the University of Cambridge who led the team of researchers who prepared the report, estimated that scientists are developing more than 600 drugs for nervous system disorders.

As history teaches, most of these funds will not pass through the registration cordons, but, given their large number, a significant proportion will certainly be approved by the relevant authorities. And, although none of the companies working on cognitive stimulants, which are intended for the treatment of diseases, does not intend to license them for use by a wider range of people, in fact, the masses will certainly use them. At least, this can be assumed by observing the growth of the "unauthorized" use of existing drugs – for example, "Ritalin" (methylphenidate) and "Providzhil" (modafinil) by people who just want to cheer up their brain.

"Providzhil" and "Ritalin" really increase cognitive abilities in healthy people. For example, thanks to Providzhil, a person can keep one more number or element in his short-term memory (most people can keep seven arbitrary numbers in memory, but he remembers the eighth with difficulty). People taking this drug also show better results when tested for their ability to make plans. The report says: thanks to such a positive effect on normal people, these funds are increasingly being used to combat fatigue, help those who work shifts, increase mental activity in exams and relieve the effects of long-term air travel.

Earlier this year, Nature, one of the world's leading scientific journals, conducted an informal survey of its readers, among whom scientists predominate. Every 5th respondent (there were 1400 of them in total) reported that he took Ritalin, Providzhil or beta-blockers (drugs that can suppress anxiety) for reasons unrelated to medical indications. Respondents used these medications to stimulate concentration, concentration or memory. 62% of this fifth of respondents took Ritalin, and 44% – Providzhil. Most of them bought these medicines by prescription or on the Internet.

Given such survey results, as well as the likely emergence of many new drugs of this kind, many, including the authors of the report, believe that the use of cognitive stimulants will significantly expand.

There are several approaches to stimulating cognitive abilities. One of them, as explained by Trevor Robbins, a colleague of Sir Gabriel at Cambridge and the working group, is to "flip the switches" of the brain. Roughly speaking, the networks of neurons in the brain can be likened to electrical wires. Neurotransmitters push switches, turning on or off the current.

Thank you for remembering

One of these neurotransmitters is glutamic acid. It turns on the "current" in the networks responsible for the formation of memories. Substances from the newly discovered category of pharmaceuticals – ampakins – enhance the effect of glutamic acid and thereby facilitate memorization.

Ampakin-based drugs are developed, for example, by Cortex Pharmaceuticals from Irvine, California. One of the drugs she created, called the code designation CX717, in order to hide its exact composition, is now undergoing clinical trials as a cure for Alzheimer's disease in the elderly. The first experiments have already shown that the drug can increase the reaction rate in humans. Unlike caffeine, amphetamines and other stimulants, CX717 does not increase blood pressure or pulse rate. It does not cause any "ecstasy", which means it is unlikely to be the cause of drug addiction.

Paradoxically, another glutamic acid booster, D–cycloserine, is now being tested for the ability not to stimulate memorization, but to erase memories. The answer is that the process of forgetting what has been learned ("extinction", as neurophysiologists put it in their professional jargon) is similar in its mechanisms to learning.

Reacting with certain glutamic acid receptors, D-cycloserine selectively stimulates forgetting, suppressing the consequences of established chains of associations – for example, anxiety, drug addiction and phobias. According to Dr. Robbins, experiments have shown that if, simultaneously with a dose of D-cycloserine, a rat is shown an irritant that was previously associated with fear, a bad memory can be erased. This may help not only to get rid of unpleasant memories – for example, causing post–traumatic stress syndrome - but also to return the brain of a chemically dependent person to its original state. For example, it will be possible to remove triggers from the brain that encourage a person to smoke.

According to Dr. Robbins, another approach to stimulating cognitive abilities involves the use of a mediator called acetylcholine. Synapses reacting to this molecule are called "cholinergic". They manage concentration of attention, concentration on a certain thought and higher thought processes, as well as memory. In Alzheimer's disease, it is the cholinergic system that is destroyed.

In this regard, scientists are interested in drugs that inhibit the breakdown of acetycholine, as well as nicotine, which has the same effect. According to Dr. Robbins, cholinergic drugs may slightly increase the reaction rate and other secondary cognitive abilities, and similar drugs "may potentially be useful to healthy people."

Thus, cheering up the mind may soon become a major area of business. Although drugs are being developed to treat diseases, it will be difficult to prevent their use by healthy people. Actually, there is no special need for this, if the drugs do not have negative side effects. If so, they will have a very positive side effect on the incomes of their producers.

Portal "Eternal youth" www.vechnayamolodost.ru26.05.2008

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