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Old 08-19-2011
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Default neuroQ

Drug X applied to a nerve axon decreases the duration of the action potential without affecting the resting potential or peak amplitude of the action potential. Which of the following is the most likely mechanism of action of Drug X?
(A) Block of voltage-dependent Na+ permeability
(B) Decrease in the rate of Na+ inactivation
(C) Decrease in voltage-dependent Na+ permeability
(D) Increase in the rate of voltage-dependent
changes in K+ permeability
(E) Inhibition of the Na+ľK+ pump
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Old 08-19-2011
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Quote:
Originally Posted by surez18 View Post
Drug X applied to a nerve axon decreases the duration of the action potential without affecting the resting potential or peak amplitude of the action potential. Which of the following is the most likely mechanism of action of Drug X?
(A) Block of voltage-dependent Na+ permeability
(B) Decrease in the rate of Na+ inactivation
(C) Decrease in voltage-dependent Na+ permeability
(D) Increase in the rate of voltage-dependent
changes in K+ permeability
(E) Inhibition of the Na+ľK+ pump

I would go with option D - Increasing the RATE of voltage dependent changes...
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Old 08-19-2011
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think its D. w/ potassium perm increase the cell will repolarize faster decreasing the duration of the action.
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Old 08-19-2011
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Its D
I increased K+ permeability will lead to increased K+ efflux =>early repolarisation of membrane=> decreased action potential duration
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Old 08-22-2011
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Whats the answer!!!!!!!!!
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Old 08-22-2011
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Correct Answer

Ddddddddddddddd
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