Possible Interaction: Tetrodotoxin and Calcium Supplement

“Inhibition of synaptic activity with N‐type Ca2+ and Na+ channel blockers, ω‐conotoxin GVIA, and tetrodotoxin , increased the run‐lengths of the directed transport.”

“In the presence of calcium , a closely related co-release of noradrenaline and NPY was also observed during administration of veratridine (10 μM); it was completely prevented by tetrodotoxin (1 μM).”

“Blockade of voltage-gated channel-mediated Na+ entry with tetrodotoxin (1 microM) or lidocaine (200 microM) significantly reduced excess intraneuronal Na and Ca accumulation in all compartments and decreased respective K loss.”

“The removal of extracellular Ca2+ (n=15) or the application of 10–6M tetrodotoxin (n=16) blocked this response.”

“ Abstract Calcium ions block the open configuration … tonic binding of TTX to the closed state of sodium channels in very different ranges of extracellular concentration, [Ca]O. We measured the … in channels expressed in Xenopus oocytes by α-subunits from rat brain (rBIIa) or adult rat skeletal muscle (rSkM1).”

“Na+ and Ca++ currents were blocked by the addition of 10 microM TTX and 3 mM CoCl2; Cs+ replaced K+ both intra- and extracellularly.”

“Addition of tetrodotoxin (10 microM) to, or omission of calcium from, the perfusion medium reduced the spontaneous output of 5-hydroxytryptamine by 60-70% and caused a near complete inhibition of the effect of low frequency (3 Hz) electrical stimulation of the dorsal raphe nucleus.”

“ Calcium APs of two distinct types, differing in duration and rate of rise, were observed when cultures were exposed to tetrodotoxin.”

“When both voltage-dependent Ca and Na conductances were blocked by application of Mn2+ and TTX , respectively, ACh produced voltage-dependent increases in Ra (31%) without significant depolarization.”

“At 40 days, however, BTX and denervation caused a marked decrease and TTX resulted in a smaller decline in Ca uptake.”