välittäjäaineen

Välittäjäaineen, known in English as neurotransmitter, is a chemical messenger that transmits signals across a chemical synapse, such as a neuromuscular junction, from one neuron (nerve cell) to another "target" neuron, muscle cell, or gland cell. Neurotransmitters are released from the synaptic bouton of a presynaptic neuron and bind to and activate the receptors of the postsynaptic neuron. This binding triggers a response in the postsynaptic neuron, which can be either excitatory or inhibitory.

There are many different types of neurotransmitters, each with its own specific function. Some of the most well-known neurotransmitters include acetylcholine, dopamine, serotonin, norepinephrine, and gamma-aminobutyric acid (GABA). Acetylcholine plays a role in muscle contraction and memory. Dopamine is involved in reward, motivation, and motor control. Serotonin affects mood, sleep, and appetite. Norepinephrine is associated with the fight-or-flight response. GABA is the primary inhibitory neurotransmitter in the central nervous system, helping to regulate neuronal excitability.

The precise functioning of neurotransmitters is crucial for a wide range of physiological and psychological processes. Imbalances or dysfunctions in neurotransmitter systems are implicated in various neurological and psychiatric disorders, including depression, anxiety, Parkinson's disease, and schizophrenia. Research into neurotransmitters continues to be a significant area of study in neuroscience, aiming to understand their complex roles and develop more effective treatments for related conditions.