Final answer:
Acetylcholine is released into the synaptic cleft during neurotransmission, binding to receptors and causing depolarization for signal transmission. Acetylcholinesterase breaks down acetylcholine, ending the signal and resetting the synapse.
Step-by-step explanation:
The hydrolysis of acetylcholine (ACh), a neurotransmitter, is crucial in neuronal transmission across a synapse. ACh is released from the presynaptic neuron and binds to receptors on the post-synaptic membrane to relay neural impulses. Acetylcholinesterase (AChE), present on the post-synaptic membrane, is essential because it terminates the signal by hydrolyzing ACh.
During neurotransmission, when an action potential reaches the presynaptic neuron's terminal, calcium ions (Ca²+) trigger the release of ACh into the synaptic cleft. ACh diffuses across the cleft, binds to receptors on the post-synaptic neuron or muscle cell, and causes a change in permeability, allowing ions like Na+ to flow in, depolarizing the membrane and creating an end-plate potential or action potential.
The process is crucial for muscle contractions, as well as for sensory input and cognitive functions in the central nervous system. AChE's role in hydrolyzing ACh is vital for ending the transmission and preparing the synapse for the next signal, avoiding prolonged activation which can be detrimental to neuronal function.