Cytoplasmic and nuclear volume in the neurons of the spinal ganglia of the lizard: observation during hypertrophy.

It is known that neurons can undergo a process of hypertrophy when they are involved in an increase of the innervation field. This situation is easily observable in the spinal ganglia of the lizard which innervate the regenerated tail. Morphometric analysis carried out on the whole neuronal population of such ganglia has shown a greater increase of cytoplasmic volume with regard to the nuclear volume during hypertrophy (a decrease of the nucleo-plasmic index). Hypertrophy in the neurons of lizard spinal ganglia has been analysed both in still growing animals and in adults after amputation of the tail, showing analogous behaviour in the two situations. This suggests that the physiological growth of the animal does not influence the reaction to hypertrophy.