True about hypnotic drugs is: September 2005
**Core Concept**
Hypnotic drugs are a class of medications used to induce and maintain sleep in individuals with insomnia or other sleep disorders. They work by enhancing the activity of the neurotransmitter gamma-aminobutyric acid (GABA) in the central nervous system, which has a calming effect on the brain.
**Why the Correct Answer is Right**
The correct answer is related to the mechanism of action of hypnotic drugs. Hypnotics, such as benzodiazepines and non-benzodiazepines, bind to GABA receptors in the brain, increasing the frequency of GABA-mediated chloride ion influx into neurons. This results in a decrease in neuronal excitability, leading to sedation and sleep.
**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect because hypnotic drugs do not primarily work by inhibiting the enzyme monoamine oxidase (MAO).
**Option B:** Incorrect because hypnotic drugs do not primarily work by blocking the action of acetylcholine at muscarinic receptors.
**Option C:** Incorrect because hypnotic drugs do not primarily work by stimulating the release of the neurotransmitter serotonin.
**Clinical Pearl / High-Yield Fact**
It's essential to note that hypnotic drugs can cause dependence and withdrawal symptoms when used for extended periods. Therefore, they should be used judiciously and for the shortest duration possible.
**Correct Answer: A. None of the above.**