Mechanism of action of neurotransmitters
In order for the cells in the nervous system to send signals throughout the body, they need to communicate with each other through neurotransmitters. These substances move between synapses to transmit signals to the next neuron.
Physiologically, the nervous system is divided into two parts, the central nervous system and the peripheral nervous system. The central nervous system is made up of the brain and spinal cord, which is the control center and command all activities of the body. The peripheral nervous system is a collection of nerves spread throughout the body, carrying important messages, communicating between the body and the brain.
Nerve cells, also known as neurons, are cells responsible for transmitting signals from the central nervous system to organs, as well as responding to information from organs back to the brain. .
1. What is a neurotransmitter?
When there is a signal from the central nervous system, a nerve impulse is formed, which is transmitted through the nerve cells to the target organ cell. Between neurons are synapses, also known as synaptic clefts.
Neurotransmitters are essentially chemical substances that help transmit impulses across synaptic clefts between two adjacent neurons, or between a neuron and the target cell to which the nerve impulse is directed. muscle cells, gland cells).
2. Mechanism of action of neurotransmitters
Nerve signals from the brain will form nerve impulses, which are action potentials that propagate along the axon of the neuron. The action potential is caused by the exchange of Na+ and K+ ions across the axon membrane. Nerve impulse conduction is faster on myelinated neurons.
Neurons produce enzymes that help synthesize neurotransmitters. These substances are stored in vesicles in the synapse located at the nerve endings. An action potential that is propagated to the end of the neuron opens the calcium channels there. The released calcium fuses the membrane of the storage vesicles into the axon terminal cell membrane. Membrane fusion forms a vent, allowing neurotransmitters to be released into the synaptic cleft.
After diffusing across the synaptic cleft, the neurotransmitters bind to specific receptors located on the cell membrane in adjacent neurons or target cells. Receptors and neurotransmitters operate in a lock-key mechanism. A specific neurotransmitter binds to only one type of receptor, triggering changes in the receptor cell. Transmitters can induce a stimulus response, further transmitting the signal to the underlying cell. Or it can also block the signal, preventing the impulse from being transmitted (inhibitory response).
Neurotransmitters, after interacting with receptors, will evolve in the following cases:
Degeneration: structural changes by the enzyme to become inactive, unable to attach to the corresponding receptor. Diffusion: transmitters enter surrounding tissues and are eliminated. Reuptake: the transmitter is pumped back into the storage sac at the presynaptic axon terminal for reuse.
3. Pathological disorders of nerve conduction
Any abnormality on the mechanism of action of neurotransmitters leads to pathological conditions such as:
Imbalance of neurotransmitters: Alzheimer's disease, autism, depression, epilepsy epilepsy, Huntington's disease, Parkinson's disease, schizophrenia. Inactive receptors: myasthenia gravis. Decreased uptake of neurotransmitters in neurons: amyotrophic lateral sclerosis. Defects of ion channels: cyclic ataxia, cyclic paralysis of hyperkalemia/hypokalemia, congenital dystonia. Poisoning: poisoning by microorganisms such as the virulent Clostridium botulinum, the fungus Amanita muscaria. Vinmec International General Hospital is a high-quality medical facility in Vietnam with a team of highly qualified medical professionals, well-trained, domestic and foreign, and experienced. A system of modern and advanced medical equipment, possessing many of the best machines in the world, helps to detect many difficult and dangerous diseases in a short time, supporting the diagnosis and treatment of effective doctors. most fruitful. Therefore, when there are any health problems, customers can contact the Hospital for examination and instructions from specialists and doctors.
Reference source: msdmanuals.com - slideshare.net - verywellmind.com