A QUANTITATIVE STUDY OF THE EFFECT OF EARLY CHLORPROMAZINE (CPZ) TREATMENT ON THE DEVELOPMENT OF THE MUSCULAR AND NEURAL SYSTEMS OF AXOLOTL LARVAE

ABSTRACT

A quantitative microscopic evaluation of the action of CPZ on Axolotl embryos was made. Counts of neuron nuclei and muscle fibres were made on transverse sections of two representative larvae from each of the experimental groups used. Nine defined planes were counted in the nervous system and six in the muscular system of each larva. CPZ caused, under most experimental conditions, a decrease of the number of muscle fibres, in extreme cases to about 35%–37% of the controls. This was shown to be a specific effect and not the result of a general retardation of development.

In the nervous system, too, a decrease in cell numbers occurred, although never to less than 68% of the controls. Extreme treatment with CPZ caused a larger extent of reduction of muscle fibres than of the number of nerve nuclei.

Whereas the muscle fibres and neural nuclei of the six body planes reacted similarly to CPZ treatment, there was a statistical indication that the various brain regions reacted differently.