title: The action of the sodium ionophore, monensin, or transmitter release at the frog neuromuscular junction.
abstract: The action of the sodium ionophore, monensin, on spontaneous and evoked transmitter release at the frog neuromuscular junction was studied. Ringer's solutions with low calcium concentrations (0.4 mM or 0 Ca 1 mM EGTA) were used to bathe the preparation. Following addition of monensin in the bathing solution: (1) substantial increases in miniature end-plate potential frequency occurred; (2) tetanic nerve stimulation caused increases in potentiation of approximately 10 times over control values; (3) there was a dual action on the amplitude of the end-plate potential. We conclude that sodium ions take part in the regulation of transmitter release at the neuromuscular junction.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D005071:Evoked Potentials / Q000187:drug effects; D005663:Furans / Q000494:pharmacology*; D008985:Monensin / Q000494:pharmacology*; D009469:Neuromuscular Junction / Q000187:drug effects / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000378:metabolism; D011894:Rana pipiens; D011895:Rana ridibunda
chemical_list: D005663:Furans; D018377:Neurotransmitter Agents; D004533:Egtazic Acid; D008985:Monensin; D002118:Calcium