Acetylocholine is a neurotransmitter that can activate an action potential (nerve impulse) in a postsynaptic neuron (Figures 1 and 2). A postsynaptic neuron is the next neuron in the chain of neurons receiving impulses. A researcher is investigating the effect of a particular
neurotoxin that causes the amount of acetylcholine released from the presynaptic neuron to increase.
(a). Describe the immediate effect of the neurotoxin on the number of action potentials in a postsynaptic neuron. Predict whether the
maximum membrane potential of the postsynaptic neuron will increase, decrease, or stay the same.
(b). The researcher proposes two models, A and B, for using acetylcholinesterase (AChE), an enzyme that degrades acetylcholine, to prevent the
effect of the neurotoxin. In model A, ACHE is added to the synapse. In model B, ACHE is added to the cytoplasm of the postsynaptic cell. Predict
the effectiveness of EACH proposed model. Provide reasoning to support your predictions.