Acetylcholinesterase density and turnover number at frog neuromuscular junctions, with modeling of their role in synaptic function

Lili Anglister*, Joel R. Stiles, Miriam M. Salpetert

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

78 Scopus citations

Abstract

Acetylcholinesterase (ACNE) density at the neuromuscular junction of frog cutaneous pectoris muscle was determined by electron microscope autoradiography and biochemistry to be t600 sites μm-2 of postsynaptic area,t4-fold lower than all previous reports (mouse), whereas the hydrolytic turnover number was 9,500 s-1, well within the range (2,000-16,000 s-1) for ACNE from other species. Monte Carlo computer simulations of miniature endplate currents showed that for vertebrate neuromuscular junctions with different morphologies, an AChE density of only ∼400 sites μm-2 and a turnover number of only ∼1,000 s-1 are sufficient for normal quantal currents. Above these critical lower limits, miniature endplate currents were essentially insensitive to AChE density and turnover number values up to 5,000 sites μm-2 and 16,000 s-1, respectively.

Original languageAmerican English
Pages (from-to)783-794
Number of pages12
JournalNeuron
Volume12
Issue number4
DOIs
StatePublished - Apr 1994

Bibliographical note

Funding Information:
We thank Rachel Cohen and Maria Szabo for excellent technical assistance, Tom Bartol, Tom Podleski, and Ed Salpeter for useful discussion, and Debbie Moslehi for preparing the manuscript. This work was supported by NIH NS09315 and GM10422 (M. M. S.), NIH fellowship NSO9126(1. R. S.), US-Israel Binational Science Foundation grant BSF89-00502 (L. A. and M. M. S.), and the Bruno Goldberg Endowment Fund (L. A.). Computer simulations were conducted at the Cornell National Supercomputer Facility, a resource of the Center for Theory and Simulation Science and Engineering, Cornell University, Ithaca, NY.

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