Hermovälittäjäaineilla

Hermovälittäjäaineilla, also known as neurotransmitters, are chemical messengers that transmit signals across a chemical synapse, from the presynaptic neuron to the postsynaptic neuron. They are synthesized in the neuron and stored in vesicles in the presynaptic terminal. When an action potential arrives at the presynaptic terminal, it triggers the release of neurotransmitters into the synaptic cleft. These neurotransmitters then bind to specific receptors on the postsynaptic membrane, causing a change in the electrical potential of the postsynaptic neuron.

There are many different types of neurotransmitters, each with its own unique function. Some of the most well-known neurotransmitters include acetylcholine, dopamine, serotonin, and norepinephrine. Acetylcholine is involved in muscle contraction and learning and memory. Dopamine is associated with reward, motivation, and motor control. Serotonin plays a role in mood, sleep, and appetite. Norepinephrine is involved in the body's stress response, as well as alertness and attention.

The action of neurotransmitters can be excitatory or inhibitory. Excitatory neurotransmitters increase the likelihood that the postsynaptic neuron will fire an action potential, while inhibitory neurotransmitters decrease this likelihood. The balance between excitatory and inhibitory neurotransmission is crucial for proper nervous system function. Dysregulation of neurotransmitter systems has been implicated in a variety of neurological and psychiatric disorders, such as depression, anxiety, schizophrenia, and Parkinson's disease.

The removal of neurotransmitters from the synaptic cleft is essential to terminate the signal and allow for subsequent transmission. This can occur through reuptake by the presynaptic neuron, enzymatic degradation in the synaptic cleft, or diffusion away from the synapse. Understanding the mechanisms of neurotransmitter synthesis, release, action, and removal is fundamental to understanding how the nervous system functions and how to treat disorders affecting it.