PTX-sensitive and -insensitive synaptic modulation at the frog neuromuscular

Y. Sugiura, C. P. Ko

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Pharmacological manipulations were used to examine the role of G proteins in modulating synaptic transmission at the frog neuromuscular junction. Pertussis toxin (PTX, a G protein antagonist) increased end-plate potential (epp) amplitude but had no effect on the amplitude or frequency of miniature end-plate potentials. Mastoparan (a G protein agonist) decreased epp amplitude, while suramin (an antagonist) increased epp amplitude. The results suggest that PTX-sensitive G proteins tonically modulate synaptic transmission by reducing the amount of transmitter released in response to presynaptic action potentials. We also showed that endogenous ATP decreased transmitter release via P2 receptor in a PTX-insensitive manner. Thus, at least two distinct mechanisms regulate neuromuscular transmission; one is coupled to PTX-sensitive G proteins and the other is not. (C) 2000 Lippincott Williams and Wilkins.

Original languageEnglish (US)
Pages (from-to)3017-3021
Number of pages5
Issue number13
StatePublished - Sep 11 2000


  • Heterotrimeric G protein
  • Neuromuscular junctions (NMJ)
  • Pertussis toxin (PTX)
  • Presynaptic inhibition
  • Synaptic modulation

ASJC Scopus subject areas

  • Neuroscience(all)


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