Acetylcholine is stored until the neurotransmitter needs to be released. After its synthesis, acetylcholine (ACh) is packaged into vesicles. Once packaged in a vesicle, acetylcholine is stored at the nerve ending until an action potential arrives and allows for its release into the synaptic cleft.

synaptic vesicles

Neurotransmitters are made in the cell body of the neuron and then transported down the axon to the axon terminal. Molecules of neurotransmitters are stored in small “packages” called vesicles (see the picture on the right).

Introduction. Acetylcholine (ACh) is an important neurotransmitter in both the central and peripheral nervous systems. ACh is synthesized in the cytoplasm of nerve terminals by the enzyme choline acetyltransferase, and is then transported into synaptic vesicles.

acetylcholine. In acetylcholine. … rapidly destroyed by the enzyme acetylcholinesterase and thus is effective only briefly. Inhibitors of the enzyme (drugs known as anticholinesterases) prolong the lifetime of acetylcholine.

Parasympathetic stimulation of the heart releases acetylcholine onto M2 receptors which are coupled to a Gi protein that inhibits adenylyl cyclase.

Acetylcholine is the chief neurotransmitter of the parasympathetic nervous system, the part of the autonomic nervous system (a branch of the peripheral nervous system) that contracts smooth muscles, dilates blood vessels, increases bodily secretions, and slows heart rate.

How do declining acetylcholine levels affect the muscle? Decreasing levels of acetylcholine will prevent the generation of another muscle action potential. Pumped back into the SR and stored until another action potential occurs.

The two primary sources of ACh in the brain include projection neurons that innervate distal areas and local interneurons that are interspersed among their cellular targets.

Acetylcholine itself does not have therapeutic value as a drug for intravenous administration because of its multi-faceted action (non-selective) and rapid inactivation by cholinesterase.

Example: Acetylcholine In contrast, it is inhibitory in the heart, where it slows heart rate. These opposite effects are possible because two different types of acetylcholine receptor proteins are found in the two locations.

Alzheimer’s dementia is associated with the loss of cholinergic neurons that produce acetylcholine, but drugs that increase acetylcholine levels at the synapse don’t always result in significantly improved cognition.

Acetylcholine in the brain alters neuronal excitability, influences synaptic transmission, induces synaptic plasticity, and coordinates firing of groups of neurons.