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Neuroscience

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Voltage-gated Channels and Toxins

NEURO-86ACKX

In a voltage clamp experiment, where “changes in membrane potential are prevented by injecting currents that compensate for ions flowing through voltage-gated ion channels,” researchers can manipulate the membrane potential and measure the responsive currents.

A normal voltage clamp current trace consists of an early inward current driven by sodium ion movement, and a late outward current driven by potassium ion movement. Researchers can also use drugs in their voltage clamp experiments to separate different components of the current trace, such as Tetrodotoxin (TTX) and Tetraethyl ammonium (TEA).

Based on what you know about these two common experimental drugs, which of the following statements is CORRECT?

A

TTX only blocks the voltage-gated sodium channels.

B

TTX blocks both voltage-gated sodium channels and voltage-gated potassium channels.

C

TEA blocks both voltage-gated sodium channels and voltage-gated potassium channels.

D

TEA only blocks the voltage-gated sodium channels.