Cognitive enhancers

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Dopaminergics
Dopaminergics are substances that affect the neurotransmitter dopamine or the components of the nervous system that use dopamine. Dopamine is produced in the synthesis of all catecholamine neurotransmitters, and is the rate limiting step for this synthesis. Dopaminergic nootropics include dopamine precursors and cofactors (vitamin C and vitamin B6), and dopamine reuptake inhibitors:

* Mucuna pruriens - Seed powder which contains high concentrations of levodopa (L-dopa),[28] a direct precursor of the neurotransmitter dopamine.
* Tyrosine (requires Vitamin B6 and Vitamin C) - Amino acid. Precursor to dopamine, anti-depressant, sleep reducer.
* Lazabemide - a MAO-B inhibitor and has potent membrane lipid antioxidant activity. The antioxidant effects of lazabemide are attributed to its chemical structure and direct physicochemical interactions with the membrane lipid bilayer. It is a potent antioxidant, even more powerful than selegiline (deprenyl) or vitamin E, and is used to treat Alzheimer’s disease.[29]
* L-dopa - Prescription drug and dietary supplement. Precursor to the neurotransmitter dopamine, anti-depressant.
* Phenylalanine (requires Vitamin B6 and Vitamin C) - Essential amino acid. Precursor to dopamine, anti-depressant, sleep reducer.
* Selegiline - L-deprenyl is an irreversible MAO-B inhibitor, an enzyme that breaks down dopamine. Thus, it is used to treat Parkinson's disease, and has been tested as a treatment for Alzheimer's disease.[30] It protects against the genotoxin AraC, provides neuroprotection against growth factor withdrawal in PC12 cells, protects against oxidative stress in mesencephalatic neurons, and delays neuronal cell death in the hippocampus after global ischemia.[31]
* Tolcapone - Inhibits COMT (an enzyme that breaks down the neurotransmitters dopamine, epinephrine, and norepinephrine) and increases performance in tasks depending on working memory in individuals with the val/val and val/met genotype of the val158Met polymorphism of the catechol-O-methyltransferase gene, while decreasing it in presence of the met/met version. Tolcapone presents the risk of deadly side effects.
* Yohimbe - Bark. Aphrodisiac. Boosts dopamine levels,[citation needed] though how it does this is not yet understood. Supplements are likely to have no yohimbe in them.[32] Yohimbe poses some health risks through its side-effects: it is a neuro-paralytic which slows down breathing and induces acidosis, some symptoms of which are malaise, nausea, and vomiting. Contraindicated for users of megadoses of acidic vitamins or nutrients.
* Theanine - Found in tea. Increases serotonin and dopamine levels in the brain. Increases alpha-wave based alert relaxation.
Publicat de health victorro la 04:23 0 comentarii
Etichete: Dopaminergics
Cholinergics
Cholinergics are substances that affect the neurotransmitter acetylcholine or the components of the nervous system that use acetylcholine. Acetylcholine facilitates memory, concentration, focus, and high-order thought processes (abstract thought, calculation, innovation, etc.).[citation needed] Increasing the availability of this neurotransmitter in the brain may improve these functions and increase the duration in which they may be engaged without slowing down or stopping. Oversupplying the brain with acetylcholine may have the opposite effect, temporarily reducing rather than improving mental performance.[citation needed] Cholinergic nootropics include acetylcholine precursors and cofactors, and acetylcholinesterase inhibitors:

Piracetam

Main article: Piracetam

Piracetam (Nootropil) is the original[15] and most commonly taken[16][15] nootropic supplement. It is a cholinergic agent synergistic with DMAE, Centrophenoxine, choline, Alpha-GPC and Hydergine. It increases brain cell metabolism and energy levels,[17][15] and speeds up interhemispheric flow of information (left-right brain hemisphere communication). It increases alertness,[12] improves concentration, and enhances memory. Protects neurons from hypoxia,[15] and stimulates growth of acetylcholine receptors.[citation needed] It may also cause nerves to regenerate.[citation needed] Piracetam markedly decreases the formation of neuronal lipofuscin.[18] It improves posture in elderly people.[19] It is not regulated in the US.[citation needed] It is a pyrrolidone derivative.

Aniracetam

Main article: Aniracetam

Aniracetam is a pyrrolidone derivative drug, analogous of piracetam, and considered more potent[citation needed]. Like piracetam, aniracetam protects against some memory impairing chemicals, such as diethyldithiocarbamate and clonidine.[20] Also like piracetam, aniracetam may enhance memory in aging adults by increasing levels of brain biogenic monoamines, which are beneficial to learning and memory.[13] Both racetams have possible therapeutic use in treating fetal alcohol syndrome.[21] Aniracetam increases vigilance.[12] Aniracetam has shown to positively potentiate AMPA receptors.

Other cholinergics
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* Acetyl-L-carnitine (ALCAR) - Amino acid. Precursor of acetylcholine (donating the acetyl portion to the acetylcholine molecule). It is synergistic with lipoic acid.[22] Inhibits lipofuscin formation.
* Choline - precursor to acetylcholine (an essential component of the acetylcholine molecule).
o Alpha-GPC (L-alpha glycerylphosphorylcholine, Choline alfoscerate) - most effective choline precursor, readily crosses the blood-brain barrier.
o Citicoline - less expensive and similar in effect to Alpha GPC. Appears effective in rats.[23][24]
o Choline bitartrate - precursor of acetylcholine, anti-depressant.
o Choline citrate - precursor of the neurotransmitter acetylcholine, anti-depressant.[citation needed]
* DMAE - approved treatment for ADD/ADHD[citation needed], precursor of acetylcholine, cholinergic agent, removes lipofuscin from the brain, anti-depressant.
* Galantamine - acetylcholinesterase inhibitor made from chemical synthesis or extract from plants such as Red Spider Lily (Lycoris radiata).
* Huperzine A - potent acetylcholinesterase inhibitor derived from Chinese club-moss. Recent Cochrane review concluded that it appears to have beneficial cognitive effects with limited side-effects, but more evidence is needed.[25]
* Ispronicline - recently developed selective α4β2 partial agonist
* Lecithin - contains phosphatidylcholine, precursor of acetylcholine.
* Other pyrrolidone derivatives:
o Etiracetam - It increases vigilance.[12]
o Nefiracetam - Drug. Analog of piracetam, and facilitates hippocampal neurotransmission.[26]
o Oxiracetam - Drug. Analog of piracetam, and 2 to 4 times stronger. Improves memory, concentration, and vigilance. When fed to pregnant rats, the offspring of those rats were more intelligent than the offspring of rats fed a saline solution placebo.
o Pramiracetam - Drug. Analog of piracetam.
o In animal studies, nootropics such as piracetam, oxiracetam and aniracetam are known to facilitate the formation of long term memory traces and to restore object recognition in aging rats.[27] There is evidence that the beneficial effect of racetams may result from an interaction with the central glutamatergic receptor function. [27]
* Vitamin B5 - cofactor in the conversion of choline into acetylcholine, cholinergic agent, increases stamina (including mental stamina).[citation needed]

Excess acetylcholine is considered by many to be potentially harmful; see acetylcholinesterase inhibitor.

Acetylcholinesterase inhibitors

Acetylcholinesterase inhibitors function by inhibiting the cholinesterase enzyme which breaks down the neurotransmitter acetylcholine. They exist in the form of poisons and have been used as weapons, but they are also used to treat Alzheimer's patients. Donepezil, galantamine, and Huperzine A are notable among these.
Publicat de health victorro la 04:21 0 comentarii
Etichete: Cholinergics
Replenishing and increasing neurotransmitters
As the brain ages, its ability to produce and maintain youthful levels of neurotransmitters declines.[13] There are various reasons for such an insufficiency. For instance, there might be a lack of enzymes involved in the neurotransmitter synthesis. Nevertheless, in many cases, providing the brain with ample raw materials necessary to make neurotransmitters can restore them to more youthful levels and thus help maintain cognitive function at vigorous youthful levels.[citation needed] Furthermore, there are declines in immune and endocrine functioning.[14] Certain nootropics enhance immune and endocrine functioning.
Publicat de health victorro la 04:21 0 comentarii
Etichete: neurotransmitters
Stimulants
Stimulants are often seen as smart drugs. Their effects are non-specific with similar results seen in children and adults with and without ADHD. One finds improved concentration and behavior in all.[6][7][8][9] Due to their non-specific activity, stimulants have been used by writers to increase productivity,[10] as well as by the United States Air Force to improve effectiveness in combat.[11] Some scientists recommend wide spread use (of Ritalin and Adderall) by the general population to increase brain power.[4]
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Please help improve this article by adding reliable references. Unsourced material may be challenged and removed. (January 2008)

* Adrafinil (Olmifon) - Drug.
* Caffeine - Drug. Improves concentration, idea production, but hinders memory encoding. Large amounts produce the jitters. Caffeine is the most widely used psychoactive substance in the world, and may be susceptible to strong levels of tolerance.
* Coffee - Bean. Contains caffeine; brewed coffee is high in antioxidants.
* Nicergoline - Drug. Nicergoline is an ergoloid mesylate derivative used to treat senile dementia. It has also been found to increase mental agility and enhance clarity and perception. It increases vigilance.[12] Increases arterial flow and use of oxygen and glucose in the brain.
* Nicotine - stimulus barrier (aids in concentration). Stimulus barrier rebound effect (an unpleasant side effect).
* Cocaine - Drug. Schedule II. Increase extracellular dopamine and serotonin levels resulting in increased alertness and arousal.
* Methylphenidate (Ritalin) - aids in concentration, focus and stamina. Prescribed for ADHD.
* Dextroamphetamine - (Adderall, Dexedrine) - aids in concentration, focus and stamina. Prescribed for ADHD.
* Modafinil - (Provigil) - Drug.
* Phenibut -
* Theophylline -
* Amphetamines - aids in concentration, focus and stamina. Prescribed for ADHD.
* Carphedon (Phenotropil) -
Publicat de health victorro la 04:19 0 comentarii
Etichete: cognitive, enhancers, Stimulants
Availability
Currently there are several drugs on the market that improve memory, concentration, planning and reduce impulsive behavior. Many more are in different stages of development.[3] The most commonly used class of drug are the stimulants.[4]

These drugs are used primarily to treat people with cognitive difficulties: Alzheimer's disease, Parkinson's disease, ADHD. However, more widespread use is being recommended by some researchers.[5] These drugs have a variety of human enhancement applications as well and are marketed heavily on the World Wide Web. Nevertheless, intense marketing may not correlate with efficacy; while scientific studies support some of the claimed benefits, it is worth noting that many of the claims attributed to most nootropics have not been formally tested.

• Added on: Mar 13th, 2009
• Country: Romania
• Language: English

• Author: rorac2009
• Listed in: Health Medicine
• Tags: dopaminergics cholinergics