Affordable Access

Botulinum toxin: mechanism of presynaptic blockade.

Authors
  • Kao, I
  • Drachman, D B
  • Price, D L
Type
Published Article
Journal
Science (New York, N.Y.)
Publication Date
Sep 24, 1976
Volume
193
Issue
4259
Pages
1256–1258
Identifiers
PMID: 785600
Source
Medline
License
Unknown

Abstract

The mechanism of action of botulinum toxin was analyzed by the use of calcium ionophores and black widow spider venom. Addition of calcium ionophores to nerve-muscle preparations blocked by botulinum toxin did not increase the frequency of miniature end plate potentials. However, the spider venom elicited a barrage of miniature end plate potentials after blockade by botulinum. Electron micrographs of preparations treated with botulinum toxin and then the spider venom revealed clumping of synaptic vesicles at release sites in the otherwise depleted nerve terminals. These findings indicate that the action of botulinum toxin is not due to deficient storage of acetylcholine in vesicles or blockade of calcium entry into nerve terminals. They suggest that the toxin interferes with the acetylcholine release process itself, possibly by blocking exocytosis at the release sites.

Report this publication

Statistics

Seen <100 times