[Campbell Biology P.1160] Which statement best explains the mechanism by which capsaicin caus... | Practice Question

Which statement best explains the mechanism by which capsaicin causes a 'hot' sensation and its relationship to thermoreception?

  • A: Capsaicin directly activates a specific chemoreceptor that detects high temperatures.
  • B: Capsaicin binds to a receptor protein, opening a calcium channel, which also responds to high temperatures, thereby linking the 'hot' sensation to actual heat.
  • C: Capsaicin increases blood flow, leading to a sensation of warmth.
  • D: Capsaicin inhibits low-temperature thermoreceptors, creating a relative sensation of heat.

Explanation

The text explains: 'Applying capsaicin to a sensory neuron causes an influx of calcium ions. When scientists identified the receptor protein in neurons that binds capsaicin, they made a fascinating discovery: The receptor opens a calcium channel in response not only to capsaicin but also to high temperatures 42°C or higher . In essence, spicy foods taste "hot" because they activate the same receptors as hot soup and coffee.'