Peripheral compound action potential (pCAP)

A peripheral compound action potential (pCAP) is the algebraic summation of individual action potentials from a population of nerve fibers or muscle cells within a peripheral nerve or muscle bundle (StatPearls, 2023). It is an electrophysiological phenomenon rather than a discrete molecular target such as a receptor or enzyme (ScienceDirect, 2021). The pCAP is a fundamental measure used in nerve conduction studies to assess the functional integrity of the peripheral nervous system, providing data on axonal health and myelination (NIH, 2022). While not a target itself, it serves as a critical pharmacodynamic biomarker in drug development, particularly for evaluating the potency of local anesthetics and analgesics (PubMed, 2020). Drugs that target voltage-gated sodium channels, such as lidocaine or carbamazepine, result in the attenuation or elimination of the pCAP (PubChem, 2024). Changes in pCAP parameters, including amplitude, latency, and conduction velocity, are used to diagnose and monitor the progression of peripheral neuropathies and demyelinating diseases (Mayo Clinic, 2023). In the context of medical devices, evoked compound action potentials (ECAPs) are increasingly used as feedback signals for closed-loop spinal cord stimulation systems (Nature Communications, 2020). Therefore, while pCAP is not a druggable molecule, it is an essential physiological readout for assessing the impact of various therapeutic interventions on neural signaling.

Other names

Compound action potentialCAPNerve action potentialEvoked compound action potentialECAPPeripheral compound action potentials

Drugs do not target the compound action potential directly; instead, they modulate it by binding to underlying molecular targets such as voltage-gated sodium channels, thereby inhibiting the ionic currents necessary for action potential propagation (StatPearls, 2023).