Question

Dantrolene is used to treat malignant hyperthermia caused by succinylcholine because dantrolene

• A. Blocks calcium release from sarcoplasmic reticulum
• B. Induces contraction of skeletal muscle
• C. Increases the rate of succinylcholine metabolism
• D. Inhibits succinylcholine binding to nicotinic receptors

Hint:

Malignant hyperthermia is a dangerous reaction (often triggered by succinylcholine or certain anaesthetics) in which skeletal muscles release too much calcium, causing sustained muscle contraction, a sharp rise in body t

Answer 1

The Correct Option is A

Concept:
Malignant hyperthermia is a dangerous reaction (often triggered by succinylcholine or certain anaesthetics) in which skeletal muscles release too much calcium, causing sustained muscle contraction, a sharp rise in body temperature, and heat production. To treat it, we need to stop this excessive calcium release inside the muscle.

Step 1: Calcium needed for muscle contraction is stored in and released from the sarcoplasmic reticulum (SR) of muscle cells. In malignant hyperthermia, the SR releases calcium uncontrollably.

Step 2: Dantrolene works directly on skeletal muscle by blocking calcium release from the sarcoplasmic reticulum (it acts on the ryanodine receptor). With less calcium available, the muscles relax and the dangerous heat production stops.

Answer: Option (1) — Dantrolene treats malignant hyperthermia because it Blocks calcium release from the sarcoplasmic reticulum. (1)