Possible Interaction: Manganese and Tetrodotoxin

“Three methods were used to compare the activity of the MNs and the PMNs in the integrated … patterns: 1) ligatures were tightened on the ganglion trunk that connects the PMNs and MNs; 2) TTX was applied … or MN activity; and 3) sucrose pools were … PMN or MN impulse conduction.”

“When Na influx was eliminated by 1–10 microM tetrodotoxin or by substitution of TEA for bath Na, passage of depolarizing current into the axon evoked prolonged depolarizing afterpotentials that were blocked by Mn.”

“In addition to these effects, manganese also reduced membrane excitability, eliminated arrhythmic beats occurring during low-frequency electrical stimulation, and caused membrane hyperpolarization which was blocked by tetrodotoxin.”

“Activity of desensitized aggregates in the presence of TTX was augmented by elevated calcium levels, and suppressed by presumed inhibitors of slow inward current ( manganese , D600).”

“The effect of tetrodotoxin on the transmembrane potential was greatly modified by the presence of manganese , suggesting the interaction between the two drugs.”

“When applied to fiber of frog cardiac ventricle, tetrodotoxin suppresses the rate of rise of the action potential without affecting the overshoot; the suppressive effect of manganese ion is mainly on the overshoot of the action potential.”