NUCLEO-PLASMIC INDEX VARIABILITY IN DORSAL-ROOT GANGLION NEURONS OF THE LIZARD (PODARCIS-SICULA) DURING NEURONAL HYPERTROPHY

The nucleo-plasmic index was investigated in lizard dorsal root gangli on neurons from different spinal levels (cervical, thoracic, lumbar an d caudal) in normal conditions, as well as in caudal dorsal root gangl ion (DRG) neurons innervating the regenerated lizard tail (caudal hype rtrophic ganglia). Results showed no statistically significant differe nce in the distribution of nucleo-plasmic index values in DRGs from di fferent spinal levels providing sensory innervation to peripheral terr itories of different size. On the contrary, in the caudal hypertrophic ganglia, a significant shift towards lower values of the nucleo-plasm ic index was observed. This observation suggests that this 'old', and merely morphological, parameter could be regarded as a good and simple marker for the study of neuronal hypertrophy considered as a dynamic response of neurons to variations of the innervation territory. (C) 19 97 Elsevier Science Ireland Ltd.