Effects of brevetoxin-B on motor nerve terminals of mouse skeletal muscle.
1. The effects of brevetoxin-B, a red tide toxin, on motor nerve terminal activity were assessed on mouse triangularis sterni nerve-muscle preparations. The perineural waveforms were recorded with extracellular electrodes placed in the perineural sheaths of motor nerves. 2. At 0.11 microM, brevetoxin-B increased the components of waveforms associated with sodium and potassium currents while it decreased the calcium activated potassium current and the slow calcium current of the nerve terminal. The fast calcium current and slow potassium current were not affected. 3. At 1.11 microM, brevetoxin-B decreased all of the components of waveforms associated with sodium, potassium and calcium currents. 4. It is concluded that brevetoxin-B affects sodium, potassium as well as calcium currents in the nerve terminal. The effects may contribute to its pharmacological actions on synaptic transmission.
Tsai
M C
MC
Pharmacological Institute, College of Medicine, National Taiwan University, Taipei.
Chen
M L
ML
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects; D004566:Electrodes; D005260:Female; D066298:In Vitro Techniques; D008297:Male; D008387:Marine Toxins / Q000494:pharmacology*; D051379:Mice; D008813:Mice, Inbred ICR; D009046:Motor Neurons / Q000187:drug effects*; D009132:Muscles / Q000187:drug effects / Q000294:innervation*; D009411:Nerve Endings / Q000187:drug effects*; D035964:Oxocins; D015221:Potassium Channels / Q000187:drug effects; D015222:Sodium Channels / Q000187:drug effects; D013757:Tetraethylammonium Compounds / Q000494:pharmacology; D000095702:Polyether Toxins
D002118:Calcium; D015220:Calcium Channels; D008387:Marine Toxins; D035964:Oxocins; D015221:Potassium Channels; D015222:Sodium Channels; D013757:Tetraethylammonium Compounds; C043466:brevetoxin B; D000095702:Polyether Toxins