Question

Which of the following drug/toxin actions would increase the sensation of pain when applied locally to pain sensing neurons?

Check All That Apply

1.Inhibit the opening of Ca²⁺ gated channels located at the axon terminal of pre-synaptic neurons

2.Inhibit the opening of Ca2+ gated channels located at the axon terminal of pre-synaptic neurons

3.Inhibit closing of K⁺ gated channels located along axons

4.Inhibit closing of K+ gated channels located along axons

5.Increase the total number and density of excitatory ligand-gated channels located on post-synaptic neurons

6.Increase the total number and density of excitatory ligand-gated channels located on post-synaptic neurons

7.Competitive inhibition of ligand-gated channels located on post-synaptic neurons

8.Competitive inhibition of ligand-gated channels located on post-synaptic neurons

9.Inhibit opening of Na⁺ gated channels located along axonsInhibit opening of Na+ gated channels located along axons

10.Inhibit the function of neurotransmitter reuptake proteins located on pre-synaptic axon terminals

11.Inhibit the function of neurotransmitter reuptake proteins located on pre-synaptic axon terminals

Answer 1

Ans.

1.Inhibition of the opening of Ca2+ gated channels located at the axon terminal of pre-synaptic neurons, Ca+ are more positive than the resting membrane potential in sensory neurons, the opening of ion channels permeable to these ions will cause the membrane potential to shift in the positive direction and causes depolarization.

3. Inhibition of closing of K+ gated channels located along axons, electrochemical gradient for potassium is more negative than resting potential, closure of active potassium channels not only depolarizes the membrane potential but amplifies current-induced voltage fluctuations due to the resulting increase in membrane resistance.

9. Inhibition of opening of Na+ gated channels located along axons, becouse when the influx of sodium is interrupted, an action potential cannot arise and signal conduction is inhibited.