Each of the following drugs made an important contribution to understanding signal transmission in the nervous system. the mechanism of each drug's action is given. you are asked to predict particular effects that each drug will have. a. tetrodotoxin (ttx - a toxin from the pufferfish) blocks voltage-gated na+ channels. predict the effect this toxin would be expected to have on neuronal action potential generation b. tetra-ethyl ammonium (tea) blocks voltage-gated k+ channel. how would treatment of tea affect the neuronal action potential