pubmed-article:762156 | pubmed:abstractText | Two photoactivable derivatives of tetrodotoxin have been synthesized. Electrophysiological experiments on crab giant axons and competitive binding with [3H]-tetrodotoxin for the tetrodotoxin receptor indicate that they are only 4.5 to 7.5 times less active than tetrodotoxin itself. These compounds give a reversible block of the sodium channel in the dark but after ultraviolet irradiation they provoke an irreversible blockade of the channel. | lld:pubmed |