Question

Conotoxin is produced by marine cone snails. Among its effects is to block voltage-gated Ca2+ channels in neurons.

A. What anatomical part of a neuron would be affected by conotoxin?

B. How would the neuron’s action potential be affected by conotoxin? Explain, using at least TWO of the following terms: threshold, depolarization, repolarization, hyperpolarization, summation, IPSP, EPSP, exocytosis

C. If conotoxin affected a somatic motor neuron, would this toxin cause muscle weakness or increased muscle tension? Explain why.  

2.

Answer 1

B)Depolarization-activated sodium (Na+)-selective ion channels are large transmembrane proteins present in central and peripheral neurons, and skeletal, cardiac and smooth muscle.

This signal amplification is responsible for initiating and propagating action potentials, and is the defining property of excitable cells ,conotoxin affects the initial depolarization that affects the action potential.

C) yes because motor neurons supply to all muscle and responsible for all voluntary actions , hence this toxin would also have affected the muscle increasing their weakness and tension.