Peripheral nerve compound action potential (CAP)

The peripheral nerve compound action potential (CAP) is an electrophysiological phenomenon representing the algebraic summation of individual action potentials from all activated axons within a peripheral nerve bundle (StatPearls, 2023). It is not a single molecule or receptor but rather a functional readout of the collective activity of various ion channels, primarily voltage-gated sodium and potassium channels, along the axonal membranes (PubMed, 2021). In clinical and research settings, the CAP is used as a primary biomarker to assess the physiological integrity of nerves, where parameters like amplitude and conduction velocity indicate the number of functioning axons and the state of myelination, respectively (NIH, 2022). Pharmacological agents such as local anesthetics (e.g., lidocaine) target the underlying ion channels to suppress the CAP, thereby blocking pain transmission and providing regional anesthesia (PubChem, 2024). Conversely, neurotoxic substances or disease states like diabetic neuropathy can diminish the CAP, reflecting axonal loss or dysfunction (Wikipedia, 2023). Understanding the CAP is essential for evaluating the efficacy of analgesic drugs and the safety profiles of compounds that may induce peripheral nerve damage.

Other names

Compound nerve action potentialCNAPNerve action potentialCompound action potential

Drugs modulate the compound action potential by inhibiting or altering the kinetics of voltage-gated sodium channels (Nav) and potassium channels (K), which are the underlying molecular components responsible for generating individual axonal action potentials (StatPearls, 2023).