As you know, there are many synapses in the nervous system. They are necessary for the transmission of impulses. Several types of mediators are involved in this process. Among them are acetylcholine, norepinephrine, GABA, serotonin, etc. Mediators (transmitters) are necessary for signaling between neurons. In addition, thanks to them, excitation or inhibition of the muscles is carried out. With various pathologies of the nervous system, the work of neurotransmitters can be disrupted. This happens due to atrophic and degenerative processes in the brain. In these cases, drugs are used that are necessary to enhance or attenuate signaling. A similar pharmacological group includes cholinesterase inhibitors. They are used for myasthenia gravis, neuritis, amyotrophic sclerosis, Alzheimer's disease, mental pathologies.
The action of cholinesterase inhibitors
Cholinesterase inhibitors are medications that are widely used in neurology and psychiatry. They are divided into severalgroups, each of which is used in a particular case. The action of these medicines is based on blocking cholinesterase. This enzyme is present both in he althy people and in those suffering from various diseases. It is necessary for the breakdown of the neurotransmitter acetylcholine. As a result of its action, the transmitter is destroyed to choline and acetic acid. With various pathologies of the brain, gradual atrophy of the cortex occurs. As a result, some structures can be completely destroyed, including the cholinergic system. In addition to brain atrophy, degenerative processes of an autoimmune, infectious, viral nature lead to this. Due to the destruction of the nuclei of the forebrain, there is a pronounced lack of a neurotransmitter - acetylcholine. In order to avoid a deficiency of this substance as long as possible, it is necessary to act on the enzyme that destroys it. For this purpose, cholinesterase inhibitors are used. Thanks to them, the activity of the neurotransmitter can be maintained for several years.
Cholinesterase inhibitors: classification of drugs
There are several types of anticholinesterase drugs. They are classified according to the pharmacological effect on the enzyme. Some of them block cholinesterase irreversibly, others temporarily. There are 3 groups of medicines. Among them:
- Reversible blockers. These cholinesterase inhibitors affect postsynaptic signaling. Thanks to them, the action of the enzyme is temporarily interrupted. This group includes acridines and piperidines.
- Pseudo-irreversible cholinesterase blockers. The mechanism of their action is to combine with the onion part of the enzyme molecule. In addition, they are able to bind to acetylcholine receptors. The group of carbamates has similar properties.
- Irreversible cholinesterase inhibitors. Preparations of this group are called organophosphorus agents. The representative is the drug "Metrifonat".
The group of acridines includes drugs "Takril" and "Velnakrin". Representatives of carbamates - medicines "Rivastigmine", "Epistatigmine".
Indications for the use of cholinesterase inhibitors
Cholinesterase inhibitors are used to treat central muscular diseases, atrophic and degenerative brain pathologies. In addition, some medicines are available in the form of drops. They are used for increased intraocular pressure - glaucoma. Drugs that inhibit cholinesterase reversibly are prescribed for the treatment of dementia, Pick's disease, and Alzheimer's. Preference should be given to the group of piperidines, as they act selectively and have fewer side effects. Recently, indications for the use of drugs have expanded. This is due to a more detailed study of their properties. Diseases for which anticholinesterase drugs are prescribed include myasthenia gravis, intestinal atony, muscular dystrophy, amyotrophic lateral sclerosis, paralysis of the extremities of degenerative origin. Irreversible inhibitors are used for poisoning.
Contraindications for the use of anticholinesterase drugs
Medicines belonging to this group are not used for convulsive syndrome, hyperkinesis of any etiology. They are also contraindicated in patients suffering from severe heart failure, bronchial asthma, thyrotoxicosis. It is undesirable to take anticholinesterase drugs with concomitant gastric ulcer, enteritis. Medicines are not indicated for pregnant and lactating women.
Cholinesterase inhibitors: drugs of choice for Alzheimer's disease
Alzheimer's disease is an atrophic lesion of the central nervous system, in which there is amnesia, personality disorder and dementia. Scientists around the world are trying to find a cure for this pathology. With mild to moderate severity of the disease, the drug of choice is Donepezil. It belongs to reversible cholinesterase inhibitors, has a selective effect. The drug is used for the purpose of pathogenetic therapy. It is not able to completely cure the patient, but slows down the development of Alzheimer's symptoms.
