The inhibitor by Mg++ of stimulus evoked transmitter release is attributed to a decrease in surface potential on the outer surface of the presynaptic terminal and hence a lower surface calcium concentration, [Ca++]. Data on the frog neuromuscular junction are quantitatively fit by assuming that there is a negative charge density on the outer surface of the presynaptic terminal of 6.5 x 1013 charges per cm2 and that simple diffuse double layer theory is applicable. No specific binding of Mg++ or Ca++ is required. Without any additional assumptions, the inhibitory effect of univalent cations is also quantitatively predicted.
|Original language||English (US)|
|Number of pages||4|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|Publication status||Published - Jan 1 1974|
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