Retrograde labeling of primary sensory neurons with fluorescent latex microspheres: a useful tool for long term tagging of neurons

In this study we have used fluorescent microspheres to retrogradely label primary sensory neurons in dorsal root ganglia (DRGs). Following injection into peripheral nerves, the animals were allowed to survive up to 480 days. Simple profile count indicates that there is a substantial retention of the labeling still after at least 480 days, i.e. about two-thirds of a rat's life span. Moreover, the appearance of the labeling remains quite distinct. Using established markers for axon damage of DRG neurons, we could detect a slight and transient effect of the peripheral nerve injection on the gene expression pattern. It is concluded that fluorescent microspheres represents an attractive means of tagging neurons in experiments covering long time periods, (C) 2001 Elsevier Science B.V. All rights reserved.