hermovälittäjäainetta

Hermovälittäjäaine, also known as neurotransmitter, is a chemical messenger that transmits signals across a chemical synapse from one neuron to another neuron, or from a neuron to a target cell. These signals allow nerve impulses to be passed from one cell to the next throughout the nervous system. Neurotransmitters are stored in synaptic vesicles within the presynaptic terminal. When a neuron is excited, the vesicles fuse with the presynaptic membrane and release their contents into the synaptic cleft. The neurotransmitters then diffuse across the cleft and bind to specific receptors on the postsynaptic membrane, triggering a response in the target cell. This response can be either excitatory, increasing the likelihood of the target cell firing an action potential, or inhibitory, decreasing the likelihood.

There are many different types of neurotransmitters, each with its own unique chemical structure and function. Some well-known examples include acetylcholine, which plays a role in muscle contraction and learning; dopamine, involved in reward and motivation; serotonin, which affects mood and sleep; and GABA, an inhibitory neurotransmitter that helps to reduce neuronal excitability. The precise balance and interaction of these neurotransmitters are crucial for proper brain function and overall physiological regulation. Disruptions in neurotransmitter systems are implicated in a wide range of neurological and psychiatric disorders.