α-Bungarotoxin binding sites on sensory neurones and their axonal transport in sensory afferents

The autoradiographic localization of [¹²⁵I]α-bungarotoxin binding sites on primary sensory fibres was investigated. Nicotinic α-bungarotoxin binding sites were localized to a small sub-population of large dorsal root ganglion cells in the rat, monkey, cat and human dorsal root ganglia. Ligation of the sciatic nerve or dorsal root in the rat resulted in an anterograde accumulation of binding sites proximal to the dorsal root ganglion, and a small retrograde accumulation. Unilateral dorsal root section in the rat produced a loss of toxin binding sites mainly within lamina III of the dorsal horn. These results suggest that nicotinic α-bungarotoxin binding sites manufactured in large dorsal root ganglion cell bodies are transported both centrally to the spinal cord and also peripherally.