Soluvälittäjäaineet

Soluvälittäjäaineet, also known as neurotransmitters, are chemical messengers that transmit signals across a chemical synapse, from one neuron to another "target" neuron, muscle cell, or gland cell. They are essential for the functioning of the nervous system, enabling communication between nerve cells and mediating a wide range of physiological processes and behaviors.

These molecules are synthesized in neurons and stored in small sacs called synaptic vesicles within the axon terminal. When an electrical impulse, or action potential, arrives at the axon terminal, it triggers the release of these neurotransmitters into the synaptic cleft, the small gap between two neurons. The released neurotransmitters then diffuse across the cleft and bind to specific receptor proteins on the membrane of the postsynaptic cell.

The binding of a neurotransmitter to its receptor can have either an excitatory or inhibitory effect on the postsynaptic cell. Excitatory neurotransmitters depolarize the postsynaptic membrane, making it more likely to fire an action potential. Inhibitory neurotransmitters hyperpolarize the postsynaptic membrane, making it less likely to fire an action potential. This finely tuned balance of excitation and inhibition is crucial for complex neural functions.

Common examples of neurotransmitters include acetylcholine, dopamine, serotonin, norepinephrine, GABA, and glutamate. Each of these has distinct roles in the body, influencing everything from muscle contraction and mood regulation to learning and memory. Dysregulation of neurotransmitter systems is implicated in various neurological and psychiatric disorders.