The term “nootropics” was first proposed in 1972 by the author of the drug piracetam (K. Giurdja) to refer to means that have a specific activating effect on the integrative functions of the brain, stimulate learning, improve memory and mental activity, increase the resistance of the brain to aggressive effects, reinforcing cortico-subcortical bonds. Recently, a slightly different content of this term has been proposed, providing that nootropic should be considered as substances activating the higher integrative activity of the brain, restoring impaired mnemic (ie, memory-related) and mental functions that reduce neurological deficits and increase the body's resistance to extreme influences. .
Funds that fully meet these requirements currently do not exist, and one can hardly expect that drugs can be created that have such a multifaceted, complex positive effect on the most complex functions of the body. Nevertheless, the term “nootropics” entered into medical use, and drugs that possess the properties listed above to one degree or another were incorporated into the group of nootropic drugs.
The main drugs of this group are piracetam and a number of its analogues and homologues (etiracetam, oxyracetam, amiracetam, dipracetam, etc.), pyriditol, acephene, and a number of drugs that are structurally related to aminobutyric acid (aminolone, sodium oxybutyrate, pantogam, phenibut, picamilon et al.) and some others.
In terms of pharmacological properties, nootropics are different from other psychotropic drugs. They do not have a pronounced psychostimulating or sedative effect, they do not cause specific changes in the bioelectric activity of the brain. At the same time, they in varying degrees stimulate the transmission of excitation in central neurons, facilitate the transfer of information between the hemispheres of the brain, improve energy processes and blood supply to the brain, and increase its resistance to hypoxia. The most important manifestation of their action is the activation of intellectual and mnestic functions, antihypoxic activity. In an animal experiment, their positive effect on learning and memory is particularly characteristic. The ability to improve cognitive (cognitive) functions gave grounds to designate nootropil preparations as “cognitive stimulants” (<
A characteristic feature of nootropics is their antihypoxic effect. The ability to reduce the need of tissues for oxygen and increase the body's resistance to hypoxia is characteristic in varying degrees for all nootropic drugs. Sodium oxybutyrate has a particularly pronounced antihypoxic effect (see).
Nootropics are characterized by relatively low toxicity, do not cause circulatory disorders.
The mechanism of action of nootropic drugs is not well understood.
Piracetam (see formulas) is similar in chemical structure to
- aminobutyric acid (GABA) and can be considered as a synthetic analogue of this amino acid, which is the main central inhibitory neurotransmitter (see Aminolone). However, in the body piracetam does not turn into GABA and the content of GABA in the brain does not increase after the use of piracetam. However, the influence of nootropic drugs on other neurotransmitter systems of the brain, including amino acid (glutamatergic, etc.) and monoaminergic, is not excluded. It is known that piracetam enhances dopamine synthesis, increases the level of norepinephrine in the brain. Under the influence of piracetam and acephen, the content of acetylcholine at the level of synapses and the density of cholinergic receptors increase. Some nootropics increase serotonin in the brain.
Especially important in the mechanism of action of nootropes is the effect on the metabolic and bioenergetic processes in the nerve cell: activation of protein and RNA synthesis, improvement of glucose utilization, enhancement of adenosine triphosphate synthesis, antihypoxic and membrane stabilizing effect, etc.
In connection with the influence on the metabolic processes in the brain, drugs belonging to the group of nootropics have also been referred to as “neurometabolic” drugs.
Due to its properties, nootropic drugs in recent years have become widely used in various fields of medicine, including in geriatric and pediatric practice.
Subgroup Psychotropic drugs include drugs: