Throughout the nervous system, the predominant mode of neuron to neuron and neuron to effector (muscle or gland) transmission involves the conversion of an electrical event in the presynaptic neuron (A.P.) to a chemical event (secretion of neurotransmitter) and then back to an electrical event (A.P.) in the postsynaptic cell. Interference with any step in the sequence has significant effects on nerve and/or effector function.

Botulinum toxin causes paralysis. It binds to presynaptic sites at the motor end plate and prevents the release of neurotransmitter from vesicles.

A) What would happen to resting membrane potential if the sodium-potassium pump stopped working (due to a lack of ATP for example)? Explain.

B) What will happen to resting membrane potential if potassiumsuccinate were injected into the intracellular environment (cytoplasm) of a neuron? Explain.