The drug scopolamine is used to treat dizziness, motion sickness, and smooth muscle spasms. When isolated muscle cells are incubated with scopolamine, the addition of acetylcholine no longer depolarizes the muscle cell membrane or stimulates muscle cell contraction.
Which would best explain how scopolamine exerts its muscle-relaxing effects?Choose one:

A. It inhibits the opening of voltage-gated K+ channels.
B. It inhibits the transporters that pump Na+ into the muscle cell cytosol during an action potential.
C. It inhibits the opening of Ca2+ channels in the sarcoplasmic reticulum.
D. It inhibits the opening of acetylcholine-gated Na+ channels in the muscle cell membrane.
E. It inhibits the transporters that pump Ca2+ into the muscle cell cytosol during an action potential.

Answer is DIt inhibits the opening of acetylcholine-gated Na+ channels in the muscle cell membrane

Explanation:

Scopolamine is also known as hyoscine. It is used in preventing nausea and vomitting that may result from the anesthesia given during surgery.

Scopolamine is also useful in treating some certain form of muscle spasms and intestinal problems.

It should be noted that this scopolamine has many side effects like  headache, dizziness and dry mouth. The implication of its high dose is that, it will render the person unconscious for about 24hrs.

Acetylcholine is described as a neurotransmitter that perform some activities like causing muscle contraction, activating pain responses and regulating endocrine responses. Its deficiency may result to muscle weakness.

In this case, the scopolamine will inhibits the of acetylcholine channels in the muscle membrane , thereby creating a situation that will make muscle not to be able to contrast but relax.

D. It inhibits the opening of the acetylcholine-gated Na+ channel of the muscle of the membrane

Explanation:

Acetylcholine (ACh) is an organic chemical that performs several functions in the body and brain of many types of animals (including humans) as a neurotransmitter

Acetylcholine causes muscles to contract, regulates endocrine and REM sleep functions and activates pain responses

What the Acetylcholine does is that it triggers muscle contraction by opening a ligand-gated Na+ channel, which leads to membrane depolarization and contraction of the muscle cell.

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