Effect of Nav1.8 ion channel blockade on joint nociception. Figure shows a typical single unit recording of an unmyelinated C-fiber (conduction velocity: 1.38 m/sec) in response to normal and noxious rotation of MIA arthritic knee joints. Recording shows nerve firing activity before (A) and after (B) close intra-arterial injection of A-803467. Coincidental torque levels are displayed below each nerve recording. Movement-evoked afferent firing rate was reduced by local administration of the Nav1.8 ion channel blocker.