| C-Fiber | C-Fiber | Aδ-Fiber |
---|---|---|---|
Anatomical Characteristics: | Â | Â | Â |
Ganglionic Origin | Nodose | Jugular | Jugular |
Extrapulmonary Termination | No | Yes | Yes |
Intrapulmonary Termination | Yes | Yes | Few |
Substance P Expression (%) 1 | Yes (50) | Yes (90–100) | No (0) |
TRPV1 Expression 2 | Yes | Yes | Yes |
Functional Characteristics: | Â | Â | Â |
Conduction Velocity (m/sec) | <1 | <1 | ~6 |
Mechanical Threshold | High | High | High |
Sensitive to: | Â | Â | Â |
   Punctate Mechanical | Yes3 | Yes3 | Yes3 |
   Capsaicin | Yes | Yes | Yes |
   Hypertonic Saline | Unknown | Yes | Yes |
   Bradykinin | Yes | Yes | Yes |
   Acid | Yes | Yes | Yes |
   Inflation (≤50 cmH 2 O) | No | No | No |
   Deflation/Collapse | No | No | No |
   Stretch | No | No | No |
   Bronchoconstriction | No | No | No |
   ATP | Yes | No | No |
   Serotonin (5-HT) | Yes | No | Unknown |
Reflex Effects on Respiration | Apnea4 | Apnea4 | Apnea4 |