Peripheral Aδ fiber (Aδ fiber)

Peripheral Aδ fiber refers to a thin, myelinated sensory nerve fiber subtype (diameter 2–6 μm) found in the peripheral nervous system that conducts signals at moderate velocities (6–30 m/s)[6][1]. These fibers are primarily responsible for the transmission of acute, sharp ("first") pain and some thermal and mechanical sensations from peripheral tissues to the dorsal horn of the spinal cord[1][6][7]. They are essential mediators of fast pain, such as the withdrawal reflex—initiating a rapid response to noxious stimuli. The Aδ fiber is not a molecular drug target, but a neuroanatomical and physiological entity, meaning it is not a single protein, gene, or receptor but a functional class of axons defined by structure and physiology[1][6]. Local anesthetics and some physical interventions (e.g., nerve stimulation) can block Aδ fiber conduction to relieve acute pain[2][3].

Other names

A delta fiberA-delta fiberA delta nerve fiberType III fiberFast pain fiber

Blockade of voltage-gated sodium channels (inhibition of action potentials); Reversible inhibition of nerve conduction (local anesthetics); Modulation by electrical nerve stimulation.