The term "nootropics" was first proposed in 1972 by the author of the drug piracetam (K. Giurgea) to refer to agents 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 influences, strengthening cortico-subcortical connections. Recently, a slightly different content of this term has been proposed, providing that substances that activate higher integrative brain activity, restore impaired mental (i.e., memory) and mental functions, reduce neurological deficits and increase the body's resistance to extreme effects should be considered nootropic. .
Means that fully meet these requirements currently do not exist, and it can hardly be expected that drugs can be created that have such a multifaceted, complex positive effect on the complex functions of the body. Nevertheless, the term << nootropics >> came into medical use, and drugs that possess the properties listed above to one degree or another began to unify the group of nootropic drugs.
The main drugs of this group are piracetam and a number of its analogues and homologs (etiracetam, oxyracetam, amiracetam, dipracetam, etc.), pyriditol, acefen, as well as a number of drugs structurally related to - aminobutyric acid (aminolone, sodium hydroxybutyrate, pantogam, phenibut, picamilon, etc.) and some others.
According to the pharmacological properties, nootropics differ from other psychotropic drugs. They do not have a pronounced psychostimulating or sedative effect, do not cause specific changes in the bioelectrical activity of the brain. At the same time, they to one degree or another 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. Under the conditions of the experiment on animals, their positive influence on the learning and memory processes is especially characteristic. The ability to improve cognitive (cognitive) functions gave reason to designate nootropil drugs as << cognitive stimulants >> (<
A characteristic property of nootropics is their antihypoxic effect. The ability to reduce tissue oxygen demand and increase the body's resistance to hypoxia is characteristic to one degree or another for all nootropic drugs. Sodium hydroxybutyrate possesses 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 using piracetam. However, the effect of nootropic drugs on other neurotransmitter systems of the brain, including amino acid (glutamatergic, etc.) and monoaminergic ones, is not ruled out. It is known that piracetam enhances the synthesis of dopamine, increases the level of norepinephrine in the brain. Under the influence of piracetam and acefen, the content of acetylcholine at the level of synapses and the density of cholinergic receptors increase. Some nootropics increase the content of serotonin in the brain.
Of particular importance in the mechanism of action of nootropics is the effect on metabolic and bioenergetic processes in the nerve cell: activation of protein and RNA synthesis, improved glucose utilization, increased synthesis of adenosine triphosphate, antihypoxic and membrane stabilizing effects, etc.
In connection with the effect on the metabolic processes in the brain, drugs belonging to the group of nootropics were also designated as "neurometabolic" means.
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: