Signaalivälittäjäaineet

Signaalivälittäjäaineet, or neurotransmitters, are chemical messengers that transmit signals across a synapse, from one neuron (nerve cell) to another. This transmission is crucial for the functioning of the nervous system, enabling communication between neurons and thus controlling everything from simple reflexes to complex thought processes. When an electrical impulse reaches the end of a neuron's axon, it triggers the release of neurotransmitters into the synaptic cleft, the small gap between neurons. These molecules then bind to specific receptors on the surface of the receiving neuron, causing a change in its electrical potential. This change can either excite the neuron, making it more likely to fire its own electrical impulse, or inhibit it, making it less likely to fire.

There are many different types of neurotransmitters, each with unique functions and distribution in the nervous system. Some well-known examples include acetylcholine, which plays a role in muscle contraction and learning; dopamine, associated with reward, motivation, and motor control; serotonin, involved in mood regulation, sleep, and appetite; and glutamate, the primary excitatory neurotransmitter in the central nervous system. Other important neurotransmitters include GABA, the main inhibitory neurotransmitter, and norepinephrine, which is involved in the body's "fight or flight" response. The precise balance and interaction of these chemical messengers are essential for maintaining neurological health. Disruptions in neurotransmitter systems are implicated in a wide range of neurological and psychiatric disorders, including depression, anxiety, Parkinson's disease, and schizophrenia.