Mechanism of action of dantroline is ?
**Core Concept**
Dantrolene is a skeletal muscle relaxant that acts by inhibiting calcium ion release from the sarcoplasmic reticulum in muscle cells. This results in a decrease in muscle tone and contraction force.
**Why the Correct Answer is Right**
Dantrolene works by inhibiting the ryanodine receptor (RyR), a calcium channel on the sarcoplasmic reticulum. When RyR is activated, it releases calcium ions into the cytosol, leading to muscle contraction. By blocking RyR, dantrolene reduces the amount of calcium released, resulting in decreased muscle contraction force and tone. This mechanism is particularly useful in treating malignant hyperthermia, a life-threatening condition characterized by uncontrolled muscle contractions.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is not relevant to the mechanism of action of dantrolene.
**Option B:** While dantrolene does affect calcium channels, it specifically targets the ryanodine receptor, not L-type calcium channels.
**Option C:** Dantrolene does not work by inhibiting acetylcholine receptors or affecting the neuromuscular junction.
**Clinical Pearl / High-Yield Fact**
Dantrolene is the only specific treatment for malignant hyperthermia, making it a crucial medication in anesthesiology.
**Correct Answer:** C. Inhibition of ryanodine receptor.