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.  

Answer 1

A. Conotoxin is produced by marine cone snails they paralyze their prey by blocking or inhibiting various targets of nervous system.The anatomical part of neuron would be affected by conotoxin is located different domain of its plasmamembrane

B. when action potential reaches the terminal it activates voltage dependent calcium channels allowing calcium ions to flow into terminal calcium is most important element in neurotransmitter release ,but incase of conotoxin affected ,calcium channels are blocked and neurotransmitter release is inhibited so that action potential is degenerated

C. If conotoxin affected a somatic motor neuron, would this toxin cause muscle weakness because calcium triggers interation of actin and myosin ,it would not happen in this case contraction of muscles is absent ,causes muscle weakness