Hermovälittäjäaineen

Hermovälittäjäaineen, commonly known as neurotransmitters in English, are chemical messengers that transmit signals across a synapse, the junction between two nerve cells, or from a nerve cell to a target cell such as a muscle cell. These molecules play a crucial role in the functioning of the nervous system, enabling communication between neurons and facilitating a wide range of physiological and psychological processes.

The synthesis and storage of neurotransmitters occur within the presynaptic neuron, the cell that releases the signal. When an electrical impulse, or action potential, reaches the end of the presynaptic neuron, it triggers the release of neurotransmitters into the synaptic cleft, the small gap between the neurons. These released molecules then diffuse across the cleft and bind to specific receptors on the postsynaptic neuron, the cell that receives the signal. This binding initiates a response in the postsynaptic cell, which can be either excitatory, increasing the likelihood of an action potential, or inhibitory, decreasing it.

There are numerous types of neurotransmitters, each with distinct chemical structures and functions. Examples include acetylcholine, which is involved in muscle contraction and learning; dopamine, associated with reward, motivation, and motor control; serotonin, which influences mood, sleep, and appetite; and norepinephrine, which plays a role in the body's stress response. The precise balance and activity of these chemical messengers are vital for maintaining normal brain function and overall health. Imbalances in neurotransmitter levels or receptor function are implicated in various neurological and psychiatric disorders.