Number of acetyl choline molecules in cholinergic motor nerve endings (probably per vesicle)

Value 6000 molecules/motor nerve ending
Organism vertebrates
Reference Riveros N, Fiedler J, Lagos N, Muñoz C, Orrego F. Glutamate in rat brain cortex synaptic vesicles: influence of the vesicle isolation procedure. Brain Res. 1986 Oct 29 386(1-2):405-8. p.407 right column bottom paragraphPubMed ID2877717
Primary Source Kuffler SW, Yoshikami D. The number of transmitter molecules in a quantum: an estimate from iontophoretic application of acetylcholine at the neuromuscular synapse. J Physiol. 1975 Oct251(2):465-82. abstractPubMed ID171380
Method (Primary source abstract:)"The sensitivity of the subsynaptic membrane of twitch muscles of the frog and snake to iontophoretically applied acetylcholine (ACh) was determined...The sensitivity of the subsynaptic membrane to iontophoretically applied ACh, using the linear slopes of dose-response curves, in preparations from frog and snake treated with anticholinesterases was usually about 5 mV/pC. It follows that 6000 molecules of ACh are sufficient to produce a depolarization of 1 mV in the subsynaptic membrane."
Comments "Therefore, if one assumes that 30% of all the SVs [synaptic vesicles] present operate with glutamate as a transmitter, this would raise the number of glutamate molecules/SV to 3640, that is quite close to the estimated quantum size of 6000 ACh molecules in cholinergic motor nerve endings (primary source)."
Entered by Uri M
ID 108623