Which type of receptor is capable of undergoing adaptation in response to a sustained stimulus?

• A. Voltage-gated ion channel
• B. Nuclear hormone receptor
• C. G protein-coupled receptor (GPCR)
• D. Ligand-gated ion channel

Answer: (C)

Verified step by step guidance

1. Understand the concept of receptor adaptation: Adaptation refers to the ability of a receptor to reduce its response to a sustained stimulus over time, allowing the cell to adjust to changes in its environment.
2. Review the types of receptors listed: Voltage-gated ion channels, nuclear hormone receptors, G protein-coupled receptors (GPCRs), and ligand-gated ion channels. Each has distinct mechanisms of action and functions.
3. Focus on GPCRs: G protein-coupled receptors are known for their ability to undergo adaptation through mechanisms such as receptor desensitization, internalization, and downregulation. This allows them to modulate their response to prolonged stimuli.
4. Compare GPCRs to other receptor types: Voltage-gated ion channels and ligand-gated ion channels typically respond to changes in membrane potential or ligand binding without significant adaptation. Nuclear hormone receptors regulate gene expression and are not involved in rapid adaptation to stimuli.
5. Conclude that GPCRs are the correct answer: Based on their ability to adapt to sustained stimuli through desensitization and other mechanisms, GPCRs are the receptor type capable of undergoing adaptation.