Means affecting the central nervous system table. Drugs affecting the central nervous system. Means for relieving alcohol withdrawal

Central nervous system, its structure and functions. Control of body functions, ensuring its interaction with the environment. Neurons and their role in receiving and transmitting information, maintaining the vital functions of our body. Diseases of the central nervous system as disturbances in the processes of receiving and transmitting information within it. Medicines used in the treatment of various diseases of the central nervous system.

The nervous system coordinates the activities of the cells, tissues and organs of our body. It regulates the functions of the body and its interaction with the environment, provides opportunities for the implementation of mental processes that underlie the mechanisms of perception and thinking, memorization and learning.

The nervous system is a complex complex of highly specialized cells that transmit impulses from one part of the body to another, as a result the body is able to respond as a whole to changes in external or internal environmental factors.

Anatomically, the central and peripheral nervous systems are distinguished.

The central nervous system is represented by the brain and spinal cord.

The brain, consisting of the cortex with its numerous convolutions and the subcortex, is located in the cranial cavity. Brain mass in adults ranges on average from 1100 to 2000. From 20 to 60 years of age, brain mass and volume remain constant for each individual. If you straighten the convolutions of the cortex, it will occupy an area of approximately 20 m2.

The spinal cord is an oblong, cylindrical cord located in the spinal column. Its upper border is located at the base of the skull, and its lower border is located at the I-II lumbar vertebrae. The upper parts of the spinal cord pass into the brain, the lower parts end with the conus medullaris. The length of the spinal cord in an adult is on average 50 cm, the diameter is about 1 cm and the weight is about 34-38 g.

The peripheral nervous system includes nerve fibers and nodes located outside the central nervous system.

The main structural and functional element of the nervous system are nerve cells - neurons . The combination of neurons and the cellular elements surrounding them forms nervous tissue, the structure of which you became familiar with in.

Neurons are distinguished from other types of specialized cells by the presence of several processes that ensure the conduction of nerve impulses throughout the human body. One of the shoots - axon , as a rule, longer than the others. Axons can reach a length of 1-1.5 m. These are, for example, the axons that form the nerves of the limbs. However, they are only part of a single cell. The axons end in several thin branches - nerve endings. These endings, according to their functional significance, can be sensitive, executive, and provide interneuron contacts.

Nerve cells differ in structure, but all their types are united by a main feature: the ability to perceive irritation, enter a state of excitation, produce an impulse and transmit it further. Some neurons respond to influences from the external or internal environment and transmit impulses to the central parts of the nervous system. Such neurons are called sensitive. They, like sensors, permeate our entire body. They constantly measure temperature, pressure, composition and concentration of environmental components and other indicators. If these indicators differ from the standard ones, sensitive neurons send impulses to the corresponding part of the nervous system. The nervous system responds to these impulses and sends signals through executive neurons to tissues and organs, prompting them to act. This action becomes a corresponding decrease or increase in the production of biologically active substances by cells ( secret ), dilation or contraction of blood vessels, contraction or relaxation of muscles.

The nervous system provides reflexive, unconscious reactions of the body to environmental influences. In we gave a description of the simplest reflex arc (see), in which there is a direct connection between sensitive and executive neurons. Such a connection underlies any reflex reaction that occurs without the participation of consciousness. Indeed, we have no time to think when we touch a hot stove. If we start thinking: “My finger is on a hot stove, it’s burned, it hurts, I should remove my finger from the stove,” then the burn will occur much earlier than we take any action. We simply pull our hand away without thinking and without having time to realize what happened. This is an unconditioned reflex and for such a response, the connection of the sensory and executive nerves at the level of the spinal cord is sufficient. We encounter similar situations thousands of times and simply don’t think about it.

Other reflex responses are very complex and involve many sensory and executive neurons.

Reflexes that are carried out with the participation of the brain and are formed on the basis of our experience are called conditioned reflexes. We act according to the principle of a conditioned reflex when we drive a car or perform various mechanical movements. Conditioned reflexes make up a significant part of our daily activities.

Regardless of the type of neurons, the transmission of a nerve impulse along their chain occurs chemically in places where the nerve endings of one neuron approach others. These interaction points are called synapses (Look ). The presynaptic part of the interneuron contact contains vesicles with an intermediary ( mediator ), which release this chemical agent in synaptic cleft when a pulse passes. Next, the transmitter interacts with specific receptors on the postsynaptic membrane, as a result of which the next nerve cell enters a state of excitation, which is transmitted even further along the chain. This is how nerve impulses are transmitted in the nervous system. You can learn more about the operation of the synapse in the next chapter. The role of mediator is performed by various biologically active substances: acetylcholine , norepinephrine , dopamine , glycine , gamma-aminobutyric acid (GABA) , glutamate , serotonin and others. Mediators of the central nervous system are also called neurotransmitters .

What we call a nerve is a collection of nerve fibers surrounded on the outside by a common connective tissue sheath. Each fiber, in turn, is composed of many sensory and motor nerve processes, also surrounded by a single connective tissue sheath. Nerves conduct impulses along a chain of neurons and from them to cells of other tissues. The cell bodies of neurons themselves can be located in the central nervous system or in peripheral nodes.

Drugs that affect the central nervous system were apparently discovered by primitive people. They are used both for medicinal purposes and to maintain vitality or create a subjective feeling of inner comfort. Everyone knows the effects of caffeine, alcohol and nicotine. Often we have to resort to painkillers and sleeping pills. Everyone knows about the properties of narcotic substances - opium, hashish, cocaine, marijuana and others. All these substances act mainly on the central nervous system, or through it and with its help on other organs.

However, excessive or prolonged consumption of substances that affect the functions of the central nervous system leads to the development of addiction, mental and physical dependence of a person on such drugs. And what was useful and helped yesterday becomes poison that destroys our body. A person can no longer do without another, each time higher dose (this especially applies to drugs and alcohol). But after temporary relief, a difficult period begins again, so difficult that in order to receive a new dose, a person ceases to control his actions and coordinate them with moral standards, he degrades. Damage is gradually caused to other organs and systems (cardiovascular system, digestive system, and so on). The person becomes disabled and dies. A drug addict is no longer able to change his life on his own; only the help of doctors can save him from inevitable death.

This group of drugs includes substances that change the functions of the central nervous system, having a direct effect on its various parts - the brain, medulla oblongata or spinal cord.

According to the morphological structure, the central nervous system can be considered as a collection of many individual neurons (a neuron is a nerve cell with all its processes), the number of which in humans reaches 14 billion. Communication between neurons is ensured by contact of their processes with each other or with the bodies of nerve cells. Such interneuron contacts are called synapses (sinapsis - connection, connection). The transmission of nerve impulses in the synapses of the central nervous system, as well as in the synapses of the peripheral nervous system, is carried out using chemical excitation transmitters - mediators. The role of mediators in the synapses of the central nervous system is played by acetylcholine, norepinephrine, dopamine and other substances.

Drugs that affect the central nervous system are usually classified according to their main effects. For example, substances that cause anesthesia are combined into the group of anesthetics, sleep-inducing substances into the group of sleeping pills, etc.

Medicines affecting the central nervous system

Anesthesia;

Anesthesia (narcosis - numbness, stunning) means a reversible inhibition of the functions of the central nervous system, which is accompanied by loss of consciousness, loss of sensitivity, decreased reflex excitability and muscle tone. In this regard, during anesthesia, favorable conditions are created for surgical operations.

The official date of the discovery of anesthesia is considered to be October 16, 1846, when the first surgical operation was performed using diethyl ether anesthesia, proposed for this purpose by W. Morton. In 1847, chloroform was first used for anesthesia in obstetric practice (D. Simpson).

In the development of ideas of general anesthesia and in the introduction of anesthesia into surgical practice, the work of the outstanding Russian surgeon N. I. Pirogov was important. Since 1847, he was the first among surgeons to widely use diethyl ether for anesthesia. In addition, together with A. M. Filomafitsky, N. I. Pirogov conducted an experimental study of the effect of ether and chloroform on the animal body.

Anesthetics have an inhibitory effect on the transmission of nerve impulses at synapses in the central nervous system. The sensitivity of synapses in different parts of the central nervous system to narcotic substances is not the same. For example, synapses of the cerebral cortex and reticular formation are most sensitive to ether for anesthesia. The synapses of vital centers (respiratory and vasomotor) located in the medulla oblongata show the least sensitivity to this drug and other anesthetics.

Classification of anesthetic drugs. Depending on the route of administration of the inhalation anesthetic agent into the body;

means for non-inhalation anesthesia (Table 6).

When comparatively assessing the properties of anesthesia agents, certain criteria are used, among which the most important are the following. Each such tool must:

have pronounced narcotic activity;

cause well-controlled anesthesia, that is, allow the depth of anesthesia to quickly change when the concentration of the drug changes;

have a sufficient narcotic breadth, i.e. a sufficiently large range between the doses (concentrations) that cause surgical anesthesia and the doses in which the substances depress respiration;

do not have any significant side effects on the body.

Ethyl alcohol;

Ethyl alcohol (C2H5OH). Based on the nature of its resorptive effect on the central nervous system, it can be classified as a narcotic-type substance. There are three stages in its action on the central nervous system: excitation, anesthesia and agonal stage.

However, ethyl alcohol is of little use as a means of anesthesia, since it causes a long stage of excitation and has an extremely small breadth of narcotic action (the anesthesia stage is very quickly replaced by the agonal stage). Research by I.P. Pavlov’s collaborators has shown that even small amounts of ethyl alcohol suppress inhibition processes in the cerebral cortex, resulting in a stage of excitation (intoxication). This stage is characterized by emotional arousal, a decrease in critical attitude towards one’s own actions, and disorders of thinking and memory.

Like other narcotic substances, ethyl alcohol has analgesic activity (reduces pain sensitivity).

With an increase in the dose of ethyl alcohol, the stage of excitation is replaced by phenomena of central nervous system depression, impaired coordination of movements, confusion, and then complete loss of consciousness. Signs of depression of the respiratory and vasomotor centers of the medulla oblongata appear: weakening of breathing and a drop in blood pressure. Severe poisoning with ethyl alcohol can lead to death due to paralysis of these centers.

Ethyl alcohol has a pronounced effect on thermoregulation processes. Due to the expansion of the blood vessels of the skin during intoxication, heat transfer increases (subjectively this is perceived as a feeling of warmth) and body temperature decreases. The increase in heat transfer, in particular, explains the fact that in conditions of low temperature, people who are intoxicated freeze faster than those who are sober.

When applied locally, ethyl alcohol, depending on the concentration, causes an irritating or astringent effect. Irritating properties are most pronounced in 40% alcohol, astringent - in 95%. In addition, ethyl alcohol has an antimicrobial effect, and therefore is widely used externally as an antiseptic. For this purpose, 70%, 90% or 95% alcohol is used.

The astringent and antimicrobial properties of ethyl alcohol are associated with its ability to denature proteins (cause their coagulation). This ability increases with increasing concentration of ethyl alcohol.

Due to its irritating effect, ethyl alcohol, when taken orally, has a pronounced effect on the functions of the gastrointestinal tract. In a small concentration (up to 20%), ethyl alcohol increases appetite and enhances the secretion of the digestive glands (in particular, the stomach glands). In high concentrations, ethyl alcohol destroys digestive enzymes, which leads to digestive disorders. Ethyl alcohol improves the absorption of various substances (including medications) in the gastrointestinal tract.

In the body, most (90-98%) of ethyl alcohol is oxidized to carbon dioxide and water, releasing a significant amount of energy. When 1 g of alcohol is oxidized, about 29.28 kJ (7 kcal) of heat is released. In this respect, it is superior to carbohydrates: 1 g of carbohydrates forms 17.15 kJ (4.1 kcal) and is only slightly inferior to fats; 1 g of fat forms 38.9 kJ (9.3 kcal). Despite this, ethyl alcohol, unlike fats and carbohydrates, cannot be recommended as an energy product. Firstly, unlike carbohydrates and fats, alcohol is not deposited in the body and does not participate in the construction of tissues; secondly, its systematic use is accompanied by the development of chronic poisoning.

Ethyl alcohol finds practical use due to its antimicrobial, astringent, irritant and analgesic properties. Most often in practical medicine, ethyl alcohol is used as an antiseptic for the disinfection of medical instruments, the surgical field, and the surgeon’s hands. The antimicrobial effect of ethyl alcohol is due to its ability to cause denaturation (coagulation) of microorganism proteins and increases with increasing concentration. Thus, 95% ethyl alcohol has the greatest antimicrobial activity. In this concentration, the drug is used to treat surgical instruments, needles, catheters, etc. However, 70% alcohol is more often used to treat the surgeon’s hands and the surgical field. This is due to the fact that alcohol of a higher concentration intensively coagulates protein substances, poorly penetrates into the deep layers of the skin and disinfects only its superficial layer.

The ability of ethyl alcohol in high concentrations to cause protein coagulation, i.e. its astringent effect is used in the treatment of burns. For this purpose, 95% alcohol is used. Low concentrations of alcohol (40%) should not be used to treat burns, since, as already indicated, ethyl alcohol only has pronounced irritating properties and does not have a noticeable astringent and antimicrobial effect.

The irritating effect of 40% ethyl alcohol is used in practical medicine when using alcohol compresses in cases of inflammatory diseases of internal organs, muscles, nerve trunks, and joints. As an irritant, ethyl alcohol has a “distracting” effect, that is, it reduces pain and improves the functional state of the affected organ.

The analgesic effect of ethyl alcohol can be used to prevent pain shock in injuries and wounds. In these cases, alcohol is administered intravenously as part of anti-shock fluids.

Sleeping pills;

Sleeping pills are medicinal substances that induce in a person a state close to natural (physiological) sleep. The practical value of sleeping pills lies in the fact that in case of insomnia, they can speed up the onset of sleep, increase its duration and depth. In small doses, sleeping pills have a sedative effect.

Among hypnotics, a distinction is made between barbituric acid derivatives (phenobarbital, etaminal sodium, barbamyl, etc.), benzodiazepine derivatives (nitrazepam) and drugs of other chemical structures (bromisal, chloral hydrate, etc.).

Sleeping pills from the group of barbituric acid derivatives (barbiturates)

Hypnotics from the group of barbituric acid derivatives (barbiturates) are close to anesthetics in terms of their effect on the central nervous system. Depending on the dose, three stages can be observed in the action of barbiturates: sleep, anesthesia and the atonal stage. The difference between the main pharmacological effects of these substances is associated only with different degrees of inhibition of central nervous system functions, which depends on the activity and dose of the drugs, as well as the route of administration.

Sleeping pills from the group of benzodiazepine derivatives

Hypnotics from the group of benzodiazepine derivatives include nitrazepam (neozepam, eunoctin, radedorm). The chemical structure and properties of this drug are similar to sibazone and other tranquilizers of the group of benzodiazepine derivatives. Like these drugs, nitrazepam has a tranquilizing effect, but differs from them in a more pronounced hypnotic effect.

Acute poisoning with hypnotics

Acute poisoning with sleeping pills usually occurs as a result of their careless use or during attempts to commit suicide. In the initial stages of poisoning, victims complain of weakness, drowsiness, fatigue, headache, and a feeling of heaviness in the head. Subsequently, signs of deep depression of the central nervous system develop: loss of consciousness, lack of response to painful stimuli, weakening of reflexes, respiratory depression, decreased body temperature, relaxation of skeletal muscles, and a drop in blood pressure.

Antiepileptic drugs;

Medicines that selectively prevent the onset of seizures in epilepsy are called antiepileptics.

Epilepsy (epilepsia - seizure) is a chronic disease of the central nervous system, manifested by periodically occurring seizures.

The following main types of epileptic seizures are distinguished:

grand mal seizures are characterized by generalized (i.e., covering the entire body) clonic and tonic convulsions occurring against the background of loss of consciousness; after a grand mal seizure there is usually a long sleep;

minor seizures occur in the form of a short-term (for a second or several seconds) loss of consciousness, but, as a rule, without noticeable convulsions;

psychomotor seizures (mental equivalents) are manifested by disturbances of consciousness, motor and mental restlessness and are often accompanied by unmotivated and reckless actions (purposeless destruction, attack, etc.).

In each specific case, epilepsy occurs with a predominance of certain forms of seizures. It is also possible to develop mental disorders, specific character changes (pettiness, suspicion, pedantry, malice, etc.) and dementia. A very severe manifestation of the disease is status epilepticus - a condition in which major seizures follow each other so often that the patient does not regain consciousness, and death may occur due to respiratory failure.

Antiepileptic drugs

One of the first effective antiepileptic drugs was phenobarbital. It has the most pronounced anticonvulsant effect during major seizures of epilepsy. However, the anticonvulsant properties of phenobarbital are combined with a hypnotic effect.

Antiparkinsonian drugs;

Parkinson's disease (shaking palsy)

Parkinson's disease (shaking paralysis) and similar conditions, designated by the term "parkinsonism", are characterized by such symptoms as sharply increased skeletal muscle tone, difficulty moving, hand tremors, mask-like face, characteristic mincing gait, etc. The disease is associated with damage to one of the subcortical formations - substantia nigra.

Normally, neurons of the substantia nigra, with the help of the transmitter dopamine, have an inhibitory effect on some subcortical formations (in particular, the caudate nucleus). In Parkinson's disease and parkinsonism, the inhibitory dopaminergic influence of the substantia nigra decreases and the excitatory influence of cholinergic neurons (in particular, cholinergic neurons of the caudate nucleus) begins to predominate, which leads to the occurrence of the above symptoms. Thus, for the treatment of Parkinson's disease and parkinsonism, it is necessary to either enhance dopaminergic influences or block the influence of cholinergic neurons.

To enhance dopaminergic effects, a dopamine precursor is used - DOPA, which is converted into dopamine in the body (Dopamine itself cannot be used for this purpose, since this compound does not penetrate the blood-brain barrier well and does not enter the central nervous system through conventional routes of administration). The levorotatory isomer of DOPA, levodopa (L-DOPA), is one of the most effective drugs for the treatment of parkinsonism. The drug is prescribed orally.

Currently, combination drugs containing levodopa and carbidopa are also used (Carbidopa prevents the conversion of levodopa to dopamine in peripheral tissues, and therefore levodopa penetrates into the brain in large quantities). Such drugs include, for example, Nakom and the similar drug Sinemet. They differ from levodopa in higher efficiency and less pronounced side effects.

Midantan (amantadine hydrochloride) has proven effective in treating parkinsonism (Midantan is also used as an antiviral agent and glutantan, whose antiparkinsonian activity is associated with the ability to enhance the release of dopamine by neurons of the substantia nigra.

The influence of cholinergic neurons can be blocked using anticholinergic drugs. For the treatment of parkinsonism, central anticholinergic blockers are used - cyclodol, norakin, etc.

Analgesics;

Analgesics (analgesics) are drugs that selectively weaken or eliminate the feeling of pain.

Pain can also be eliminated with the help of anesthesia. However, there is a significant difference between the effects of anesthetics and analgesics. Anesthesia eliminates pain while turning off consciousness and other types of sensitivity, while analgesics in therapeutic doses do not suppress any type of sensitivity other than pain and do not impair consciousness. Thus, as painkillers, analgesics are more selective in action compared to anesthetics.

Based on a number of characteristics, analgesics are divided into narcotic and non-narcotic. The main differences between them are given in table. 8.

Drugs that act on the central nervous system, depending on their overall effect, are classified into one of two classes: depressants or stimulants. One might assume that the inhibitory effect on the central nervous system is achieved by the action of antagonists, and the stimulating effect by the action of agonists, but this is not always the case.

For example, strychnine, which acts as an antagonist in inhibitory neurons, is a powerful convulsant. Morphine is an enkephalin receptor agonist and is used clinically as a strong depressant.

It is advisable to divide substances that depress the central nervous system into the following classes:

1, General anesthetics administered either by inhalation (ether, halothane) or intravenously (eg thiopental) (section 15.0). These substances depress the higher parts of the brain, and when the dose increases, they block the centers of the medulla oblongata and stop breathing. After muscle relaxants were introduced into practice in the 40s, the need for deep anesthesia during operations disappeared.

2. Hypnotics, such as chloral hydrate and barbiturates, which are much milder than general anesthetics and are administered orally. Often these drugs also have an analgesic effect. The effect of ethanol is more complex: in some people, there is predominantly depression of the sensory rather than the motor elements of the nervous system, which causes a state of anxiety -

3. Tranquilizers (anxiolytics) have a strong hypnotic effect, but act only on certain structures of the brain. They are represented by substances of the benzodiazepine class, for example diazepam (section 12.7).

4, Analgesics. Strong painkillers, such as morphine (section 12.8) and weak ones such as paracetamol, act on different nerve centers. Morphine also has a local anesthetic effect, especially on the intestines. Acetylsalicylic acid is both a mild analgesic and a widely used antirheumatic drug.

5. Anticonvulsants, do not possess - 1

SHIE has a hypnotic effect------- For example, difenin, IS-!

used for epilepsy. Phenobarbital is both an anticonvulsant and a hypnotic. >

6. Antitussives. These include; dextromethorphan, which does not have an analgesic effect,1 and codeine, which has both antitussive and analgesic activity. Coughs are softened by medicinal substances that act on peripheral nerve endings or muscles.

7. Drugs that suppress appetite are usually sympatholytic drugs, most of which stimulate the central nervous system (for example, dextramphetamine). Only fenfluramine does not have this unwanted side effect.

8. Drugs used for parkinsonism. These drugs affect areas of the brain that lack dopamine. The most commonly used is levodopa (3.43, b).

9. Neuroleptics, sometimes called “major tranquilizers” or psychotropic drugs. Examples of such drugs are aminazine (12.110) and haloperidol (12.112). Drugs of this class have antipsychotic activity and are able to suppress delusions, hallucinations and other psychopathological syndromes in patients with schizophrenia by blocking dopamine receptors in the striatum of the brain (section.

10. Hallucinogens (psychodysleptics) are currently rarely used in medical practice. Examples of such drugs: lysergic acid diethylamide (LSD) and tetrahydrocannabinol, the active principle of Cannabis indica (marijuana).

CNS stimulants (psychostimulants) are used less frequently in medicine than depressants. They are divided as follows:

1. Psychomotor stimulants, causing euphoria, a feeling of physical and mental well-being and activating the mental and physical activity of the body as a result of mobilizing the mental and physical reserves of the body. The oncoming feeling of fatigue is relieved by the next dose of the drug, and so on. Small daily portions of tea or coffee are a mild form of dependence on drugs of this type. Refusal to use almost always causes long-term consequences, the main symptom of which is a severe headache. The stimulant effect of caffeine appears to be due to its antagonistic effect on adenosine receptors in the brain. Caffeine (7.52, a) is a constant component of medications for headaches. Ephedrine (12.12) is a stronger psychomotor stimulant, but its abuse may lead to the need to increase doses due to tachyphylaxis. It often suppresses urination. A more dangerous psychomotor drug is phenamine (9.44), the mechanism of action of which is to displace norepinephrine and dopamine from the depot. The effect of phenamine can be removed by blocking the synthesis of these mediators with a small dose of CC-methyltyrosine. Apparently, both of these neurotransmitters act as true drugs in much higher concentrations than normally exist in the body. The dextrorotatory stereoisomer of phenamine (dextramphetamine) has a greater effect on the central nervous system than on the peripheral nervous system and is used for narcolepsy (“drowsiness attacks”). The use of phenamine to overcome fatigue and improve performance or achieve a narcotic effect leads to many physical and mental disorders. Disturbances in sleep patterns caused by psychomotor stimulants, even caffeine, are necessary only in some cases (for example, drivers on long trips). Theophylline (7.52.6) is almost as strong a CNS stimulant as caffeine and is used primarily to relax bronchial smooth muscle in asthma and difficulty breathing.

2. Antidepressants used for psychosis, MAO inhibitors, such as transamine (section 9.4), contribute to the achievement of unusually high concentrations of norepinephrine and 5-hydroxytryptamine in the corresponding areas of the brain. Tricyclic antidepressants, such as imizine (12.114), appear to control the levels of these mediators, but in a different way (section 12.9). Lithium carbonate, used to reduce the manic component of manic-depressive psychoses, may help in both phases. Electroconvulsive therapy likely results in the release of dopamine in the brain.

3. Antidotes for drug-induced CNS depression. These substances are currently practically not used. For example, in case of barbiturate poisoning, patients are detoxified by gastric and intestinal lavage. A typical representative of this class of analeptics (stimulants), which in large doses cause convulsions, is strychnine, which blocks the inhibitory effect of glycine in the spinal cord, and bicuculline, which, like picrotoxin, blocks the inhibitory effect of GABA.

4. Drugs that lower blood pressure by acting on the central nervous system, such as clonidine and methyldopa (section 9.4.2), appear to be selective stimulators of catecholamine metabolism in the central nervous system.

a) Caffeine (R=Me) Hemicholy cation

b) Theophyllia (R=H)

More on the topic Drugs acting on the central nervous system:

SECTION IV. FEATURES OF TECHNOLOGY OF SOME DRUGS. Chapter 23. MEDICINES MANUFACTURED BY PHARMACIES FOR INFANTS AND CHILDREN UNDER ONE YEAR OF AGE
Chapter 4 STATE REGULATION OF PRODUCTION OF MEDICINES AND CONTROL OF THEIR QUALITY. Regulatory documents. Regulation of the right to pharmaceutical activities and drug compositions

Of the large number of substances that depress the central nervous system, the following are used: narcotic, hypnotic, neuroleptic, tranquilizing, sedative, analgesic and antipyretic.

This group of drugs includes substances that change the functions of the central nervous system, having a direct effect on its various parts - the brain, medulla oblongata or spinal cord.

According to the morphological structure, the central nervous system can be considered as a collection of many individual neurons, the number of which in humans reaches 14 billion. Communication between neurons is ensured by contact of their processes with each other or with the bodies of nerve cells. Such interneuron contacts are called synapses (sinapsis - connection, connection).

The transmission of nerve impulses in the synapses of the central nervous system, as well as in the synapses of the peripheral nervous system, is carried out using chemical excitation transmitters - mediators. The role of mediators in the synapses of the central nervous system is played by acetylcholine, norepinephrine, dopamine and other substances.

Drugs that affect the central nervous system change (stimulate or inhibit) the transmission of nerve impulses at synapses. The mechanisms of action of substances on CNS synapses are different.

Thus, some substances can excite or block receptors in synapses with which certain mediators interact (6, p. 45).

For example, narcotic analgesics stimulate the so-called opiate receptors, and antipsychotics block dopamine and adrenergic receptors. There are also substances that change the synaptic transmission of nerve impulses by influencing the release of certain mediators.

For example, the antiparkinsonian drug midantan increases the release of the neurotransmitter dopamine. Certain substances alter the synaptic transmission of nerve impulses by influencing the inactivation of certain transmitters. Thus, antidepressants from the group of monoamine oxidase (MAO) enzyme inhibitors prevent the inactivation of norepinephrine under the influence of this enzyme.

For example, substances that cause anesthesia are grouped into the group of anesthetics, sleep-inducing substances are grouped into the group of sleeping pills, etc.

Below is a general classification of drugs that affect the central nervous system.

1. Anesthesia.

2. Ethyl alcohol.

3. Sleeping pills.

4. Antiepileptic drugs.

5. Antiparkinsonian drugs.

6. Analgesics.

7. Analeptics.

8. Psychotropic drugs:

neuroleptics;

tranquilizers;

sedatives;

lithium salts;

antidepressants;

psychostimulants;

g) nootropic drugs.

Among the listed substances there are drugs that have a depressing effect on most functions of the central nervous system. Such substances include anesthetics, ethyl alcohol, and sleeping pills. Along with this, many substances (antiepileptic drugs, neuroleptics, tranquilizers, sedatives) have a more selective inhibitory effect on the functions of the central nervous system.

In contrast to these substances, some drugs act on the central nervous system in a stimulating manner (for example, analeptics, psychostimulants).

There are also substances that can have a depressing effect on some nerve centers and a stimulating effect on others. For example, narcotic analgesics inhibit the perception of pain, the respiratory center, and the cough center, but stimulate the vagus and oculomotor centers.

I would like to give another classification of drugs that affect the central nervous system

Drugs of the strychnine group (medicines that primarily stimulate the functions of the spinal cord)

Drugs for the treatment of mental illnesses and neuroses (psychotropic drugs)

Anesthetics

Means for non-inhalation anesthesia

Central nervous system stimulants, analeptic drugs

Drugs that have a “tonic” effect on the central nervous system

Drugs used to treat parkinsonism

Means that improve intellectual activity of the brain/attention, memory, learning, etc. / nootropic and gamkergic drugs)

Tricyclic antidepressants

Points of action of drugs affecting the central nervous system

1 - impulse in the presynaptic fiber;

2 - synthesis of mediator;

3 - mediator storage;

4 - metabolism in the presynaptic terminal (metabolism);

5 - release of the mediator;

6 - reverse capture of the mediator;

7 - destruction of the mediator (degradation);

8 - receptor;

9 - increase or decrease in ionic conductivity

Conclusion

Thus, substances affecting the autonomic nervous system can be classified as follows:

Adrenergic agents

Antiadrenergic agents

Cholinergics

Anticholinergic drugs

However, excessive or prolonged use of substances that affect the functions of the central nervous system leads to the development of addiction, mental and physical dependence of a person on such drugs. And what was useful and helped yesterday becomes poison that destroys our body. A person can no longer do without another, each time higher dose (this especially applies to drugs and alcohol). But after temporary relief, a difficult period begins again, so difficult that in order to receive a new dose, a person ceases to control his actions and coordinate them with moral standards, he degrades. Damage is gradually caused to other organs and systems (cardiovascular system, digestive system, and so on). The person becomes disabled and dies. A drug addict is no longer able to change his life on his own; only the help of doctors can save him from inevitable death.

References

1. Vein A.M., Solovyova A.D. and Kolosova O.A. Vegetovascular dystonia, M., 1981;

2. Gusev E.I., Grechko V.E. and Burd G.S. Nervous diseases, p. 199, 547, M., 1988;

3. Lobko P.I. and others. Autonomic nervous system. Atlas, Minsk, 1988;

4. Nozdrachev A.D. Physiology of the autonomic nervous system, L., 1983, bibliogr.;

5. Pathological and anatomical diagnosis of human tumors, ed. N.A. Kraevsky et al., p. 86, M., 1982;

6. Paches A.I. Tumors of the head and neck, p. 90, M., 1983;

This group of drugs includes substances that change the functions of the central nervous system, having a direct effect on its various parts - the brain, medulla oblongata or spinal cord.

According to the morphological structure, the central nervous system can be considered as a collection of many individual neurons *, the number of which in humans reaches 14 billion. Communication between neurons is ensured by contact of their processes with each other or with the bodies of nerve cells. Such interneuron contacts are called synapses (sinapsis - connection, connection).

* (Neuron is a nerve cell with all its processes.)

Drugs that affect the central nervous system change (stimulate or inhibit) the transmission of nerve impulses at synapses. The mechanisms of action of substances on CNS synapses are different. Thus, some substances can excite or block receptors in synapses with which certain mediators interact. For example, narcotic analgesics stimulate the so-called opiate receptors, and antipsychotics block dopamine and adrenergic receptors. There are also substances that change the synaptic transmission of nerve impulses by influencing the release of certain mediators. For example, the antiparkinsonian drug midantan increases the release of the neurotransmitter dopamine. Certain substances alter the synaptic transmission of nerve impulses by influencing the inactivation of certain transmitters. Thus, antidepressants from the group of monoamine oxidase (MAO) enzyme inhibitors prevent the inactivation of norepinephrine under the influence of this enzyme.

By influencing the synaptic transmission of nerve impulses, drugs change the functions of the central nervous system and, as a result, cause various pharmacological effects. Drugs that affect the central nervous system are usually classified according to their main effects. For example, substances that cause anesthesia are grouped into the group of anesthetics, sleep-inducing substances are grouped into the group of sleeping pills, etc.

Below is a general classification of drugs that affect the central nervous system.

Medicines affecting the central nervous system

1. Anesthesia. 2. Ethyl alcohol. 3. Sleeping pills. 4. Antiepileptic drugs. 5. Antiparkinsonian drugs. 6. Analgesics. 7. Analeptics. 8. Psychotropic drugs: a) neuroleptics; b) tranquilizers; c) sedatives; d) lithium salts; e) antidepressants; f) psychostimulants; g) nootropic drugs.