OC spray operates by activating which receptor to cause tearing and burning?

• A. TRPV1 receptors
• B. NMDA receptors
• C. Dopamine receptors
• D. GABA receptors

Answer: (A)

Capsaicinoids in OC spray, especially capsaicin, activate TRPV1 receptors on sensory nerve endings. These receptors are the body’s heat and chemical irritant detectors. When TRPV1 opens, it lets in calcium and sodium, generating strong pain signals that trigger tearing, burning, eye irritation, and coughing as the body tries to flush out the irritant. This direct activation of TRPV1 explains the characteristic tearing and burning.

Other receptors don’t produce this immediate irritant response. NMDA receptors are involved in broader pain signaling and plasticity, not the direct chemical irritation from OC spray. Dopamine receptors relate to reward and movement, and GABA receptors mediate inhibition in the brain. None of these account for the acute tearing and burning caused by capsaicinoids.