Acetylcholine is stored in vesicles in the presynaptic neuron. These fuse with presynaptic membrane upon stimulation by a nerve signal, thus, generating a pulse of neurotransmitter, which diffuses across the membrane. Acetylcholine may either bind reversibly to one of two different types of acetylcholine receptors on the postsynaptic membrane or be destroyed by the acetylcholine-hydrolyzing enzyme, acetylcholinesterase.

Providing storage is as stated on the product vial and the vial is kept tightly sealed, the product can be stored for up to 24 months.
Wherever possible, you should prepare and use solutions on the same day. However, if you need to make up stock solutions in advance, we recommend that you store the solution as aliquots in tightly sealed vials at -20°C. Generally, these will be useable for up to one month. Before use, and prior to opening the vial we recommend that you allow your product to equilibrate to room temperature for at least 1 hour.