atsetüülkolinesteraas

Acetylcholinesterase, often abbreviated as AChE, is an enzyme that plays a crucial role in the nervous system of many animals, including humans. Its primary function is to break down the neurotransmitter acetylcholine (ACh). Acetylcholine is a vital chemical messenger responsible for transmitting nerve impulses across synapses, which are the junctions between nerve cells or between a nerve cell and a muscle cell.

The action of AChE is essential for the proper functioning of cholinergic synapses. After acetylcholine is released into the synaptic cleft and binds to its receptors, initiating a signal, acetylcholinesterase quickly hydrolyzes it into choline and acetic acid. This rapid breakdown of acetylcholine terminates the signal, allowing the postsynaptic membrane to repolarize and prepare for subsequent stimulation. Without this enzymatic activity, acetylcholine would remain in the synaptic cleft for too long, leading to overstimulation of the postsynaptic neuron or muscle.

This rapid hydrolysis is critical for precise and controlled nerve signaling. For example, in neuromuscular junctions, AChE ensures that muscles contract only when intended and relax promptly afterward. In the central nervous system, it is involved in processes like learning, memory, and attention.

Inhibitors of acetylcholinesterase are used therapeutically to treat various conditions. For instance, drugs that inhibit AChE can increase acetylcholine levels in the brain, which is beneficial in managing symptoms of Alzheimer's disease. Conversely, certain toxins, such as organophosphate pesticides and nerve agents, act by irreversibly inhibiting AChE, leading to a buildup of acetylcholine and causing severe, potentially fatal, neuromuscular and autonomic overstimulation.