asetýlkólín

Asetýlkólín, often abbreviated as ACh, is a neurotransmitter, a chemical messenger that nerve cells use to transmit signals to other cells. It is found in both the central nervous system and the peripheral nervous system. In the peripheral nervous system, acetylcholine plays a crucial role in muscle contraction, as it is the primary neurotransmitter at the neuromuscular junction. When a nerve impulse reaches the end of a motor neuron, acetylcholine is released into the synaptic cleft and binds to receptors on the muscle fiber, causing it to contract.

In the central nervous system, acetylcholine is involved in a variety of functions including attention, learning, and memory. It is also implicated in regulating sleep cycles and emotional states. Dysregulation of acetylcholine signaling has been linked to several neurological and psychiatric disorders, such as Alzheimer's disease, where a significant loss of cholinergic neurons is observed, contributing to cognitive decline. Myasthenia gravis, an autoimmune disorder, is characterized by impaired neuromuscular transmission due to antibodies attacking acetylcholine receptors. The synthesis of acetylcholine occurs in the presynaptic neuron from choline and acetyl-CoA, and its breakdown in the synaptic cleft is primarily mediated by the enzyme acetylcholinesterase, which terminates the signal and allows the postsynaptic cell to repolarize.