“The excitatory effect of oxytocin was enhanced by external magnesium, and the dose-response curve between oxytocin and relative … tiny muscle strips shifted to the left with increases in magnesium from 0 to 2.4 mM. Oxytocin potentiates spontaneous contractions by enhancing the … induced in 2.4-mM magnesium ….”
“These results suggest that magnesium might primarily potentiate the excitatory effect of oxytocin in electrical and mechanical activities of pregnant human myometrium at superficial sites of the plasma membrane, allowing the possibility of its intracellular action.”