Double fluorescence labelling supports electrophysiological evidence for dichotomizing peripheral sensory nerve fibres in rats.

The technique of double labelling with fluorescent tracers has been used to demonstrate that some sensory neurones in the sixth lumbar dorsal root ganglion (L6) of the rat possess peripheral processes which dichotomize into both the pudendal and sciatic nerves. Bisbenzimide (Bb) was injected into the pudendal nerve and propidium iodide (PI) into the sciatic. Double labelled neurones were observed which fluoresced with a blue nucleus and orange cytoplasm (PI) at 405 nm excitation. The double fluorescence was confirmed by microspectrophotometric measurements. Injection of Nuclear Yellow into the sciatic nerve and Fast Blue into the pudendal nerve also produced double labelled neurones in L6.