Draw graphs showing the effects on action potentials in a postsynaptic cell of effective doses for each of the listed toxins. Assume that the cell is normally brought to threshold by the stimuli applied to its inputs, so that any abnormality is due to the toxin.
1. curare (prevents receptor from binding neurotransmitter)
2. botulinum toxin (prevents neurotransmitter release)
In both cases, action potential is prevented, because the postsynaptic potential is blocked. Membrane potential would remain at resting potential, because even a subthreshold postsynaptic potential fails to appear in the absence of neurotransmitter action.
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