Tetrahydroaminoacridine and Physostigmine Have Opposing Effects on Probability of Transmitter Release at the Frog Neuromuscular Junction
Document Type
Article
Publication Date
2-11-1991
Description
The effect of 1,2,3,4-tetrahydro-9-aminoacridine (THA) on quantal transmitter release was examined at the frog neuromuscular junction. THA (3 μM) caused an increase in m (no. of quanta released) as measured by K+-evoked miniature endplate potential (MEPP) frequency. This was due to an increase in p (probability of release), as n (no. of functional release sites) was unchanged. The increase in p was dose-dependent over a range of 0.3-10 μM. By contrast, physostigmine (3 μM) caused a decrease in p, and neostigmine, which does not cross the nerve membrane, had no consistent effect on p. At the postsynaptic site, neostigmine produced the largest increase in MEPP size (79.2%), and THA produced the smallest (17.5%). The divergent effects of THA and physostigmine on p indicate a fundamental difference in their actions at the nerve terminal.
Citation Information
Provan, Spencer D.; and Miyamoto, Michael D.. 1991. Tetrahydroaminoacridine and Physostigmine Have Opposing Effects on Probability of Transmitter Release at the Frog Neuromuscular Junction. Neuroscience Letters. Vol.123(1). 127-130. https://doi.org/10.1016/0304-3940(91)90174-R PMID: 1676497 ISSN: 0304-3940