ensivälittäjäaineista

Ensivälittäjäaineet, also known as primary neurotransmitters, are a class of chemical messengers crucial for nerve signal transmission in the nervous system. These molecules are released from the presynaptic neuron and bind to specific receptors on the postsynaptic neuron, thereby influencing its electrical activity. The distinction between primary and secondary neurotransmitters lies in their direct role in initiating the postsynaptic response.

Primary neurotransmitters are synthesized within the neuron and packaged into synaptic vesicles for release. Upon arrival of an action potential at the axon terminal, these vesicles fuse with the presynaptic membrane, releasing the neurotransmitter into the synaptic cleft. The binding of the primary neurotransmitter to its receptor on the postsynaptic membrane causes a rapid change in the ion permeability of that membrane, leading to either excitation (depolarization) or inhibition (hyperpolarization) of the postsynaptic neuron. Examples of primary neurotransmitters include acetylcholine, glutamate, GABA, and norepinephrine. Their action is typically fast and transient, allowing for rapid communication between neurons. The precise effect of a primary neurotransmitter depends on the type of receptor it binds to on the postsynaptic neuron.