A novel compound binds the benzodiazepine site of GABA-A receptors and suppresses the spontaneous channel opening seen in these receptors even in the absence of any ligand. This compound is best classified as:

• A Competitive antagonist
• B Partial agonist
• C Inverse agonist ✓
• D Functional antagonist

Explanation

Receptors show constitutive (ligand-independent) activity, and an inverse agonist stabilises the inactive conformation, reducing basal signalling below the unliganded level. A neutral competitive antagonist blocks ligand binding without changing constitutive activity. A partial agonist increases activity, just less than a full agonist. Beta-carboline at the benzodiazepine site is the classic inverse agonist example, producing anxiety and convulsant activity opposite to diazepam. Recognising constitutive receptor activity is the discriminating concept here.

Reference: Goodman and Gilman's The Pharmacological Basis of Therapeutics, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.