Desensitization can involve the production of intracellular messengers that inhibit receptor signaling. Which of the following exemplifies this mechanism?

Desensitization can involve the production of intracellular messengers that inhibit receptor signaling. Which of the following exemplifies this mechanism?

• A. Receptor internalization
• B. Production of inhibitory messengers
• C. Up-regulation
• D. Increased receptor synthesis

Answer: (B)

Desensitization can occur when the cell generates intracellular messengers that dampen the signaling pathway already being activated. In this scenario, the receptor triggers production of second messengers that feed back to inhibit the signal, so the response diminishes despite ongoing stimulus. This is the illustrating mechanism in the option describing the production of inhibitory messengers. Receptor internalization is another desensitization route, but it works by removing receptors from the cell surface rather than by producing dampening messengers. Up-regulation or increased receptor synthesis would actually heighten responsiveness, not desensitize.

Desensitization can occur when the cell generates intracellular messengers that dampen the signaling pathway already being activated. In this scenario, the receptor triggers production of second messengers that feed back to inhibit the signal, so the response diminishes despite ongoing stimulus. This is the illustrating mechanism in the option describing the production of inhibitory messengers.

Receptor internalization is another desensitization route, but it works by removing receptors from the cell surface rather than by producing dampening messengers. Up-regulation or increased receptor synthesis would actually heighten responsiveness, not desensitize.