Which inhalational agent acts on NMDA receptor:-
**Core Concept**
The question is testing the knowledge of inhalational anesthetics and their mechanism of action, specifically their interaction with N-methyl-D-aspartate (NMDA) receptors. NMDA receptors are a subtype of glutamate receptors involved in synaptic plasticity and memory formation.
**Why the Correct Answer is Right**
Isoflurane is a commonly used inhalational anesthetic, and it has been shown to interact with NMDA receptors. At high concentrations, isoflurane can act as an antagonist at the NMDA receptor, reducing excitatory neurotransmission and contributing to its anesthetic effects. This interaction is thought to be one of the mechanisms by which isoflurane exerts its anesthetic properties.
**Why Each Wrong Option is Incorrect**
**Option A:** Sevoflurane, another inhalational anesthetic, does not have a significant effect on NMDA receptors. It primarily acts through modulation of GABA_A receptors.
**Option B:** Desflurane, a newer inhalational anesthetic, also does not have a significant effect on NMDA receptors. It is known for its rapid onset and offset of action, but its mechanism of action is primarily related to modulation of GABA_A receptors.
**Option C:** Xenon, a noble gas anesthetic, does not interact with NMDA receptors. Its mechanism of action is not fully understood, but it is thought to involve modulation of GABA_A receptors and inhibition of N-type calcium channels.
**Clinical Pearl / High-Yield Fact**
Inhalational anesthetics like isoflurane can have a biphasic effect on NMDA receptors, acting as antagonists at high concentrations but as agonists at low concentrations. This complex interaction highlights the importance of understanding the pharmacodynamics of anesthetic agents.
**Correct Answer: C. Isoflurane**