Changes in extracellular fluid composition which excite axons.
D000818:Animals; D001369:Axons / Q000502:physiology*; D004594:Electrophysiology; D005110:Extracellular Space / Q000502:physiology*; D066298:In Vitro Techniques; D051381:Rats; D013126:Spinal Nerve Roots / Q000502:physiology