The Electrostatic Basis of Mg++ Inhibition of Transmitter Release
Abstract
The inhibition by Mg++ of stimulus-evoked transmitter release is attributed to a decrease in surface potential, Ψ0, on the outer surface of the presynaptic terminal and hence a lower surface calcium concentration, [Ca++]0. Data on the frog neuromuscular junction are quantitatively fit by assuming that there is a negative charge density, σ, on the outer surface of the presynaptic terminal of 6.5 × 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.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- March 1974
- DOI:
- 10.1073/pnas.71.3.923
- Bibcode:
- 1974PNAS...71..923M