[An update on neurochemistry and pharmacological therapy of the cerebellar ataxias].

AIM

To review the available neurochemical data on the different cerebellar ataxias, and the therapeutic trials undertaken in the last twenty-five years.

DEVELOPMENT

The cerebellar ataxias have been classified according to the compromised structures in cortical cerebellar atrophies, olivopontocerebellar atrophies, spinocerebellar atrophies, and degenerations of the dentate nucleus and efferent tracts of the cerebellum. Episodic ataxias have been included, as they are eminently treatable. No nosological, nor genetic classification has been followed in this article. In each section, the (frequently fragmentary) neurochemical data is presented first, followed by the most relevant attempts at pharmacological therapy undertaken in the last twenty-five years. As can be observed from the reviewed data, neurochemical principles have rarely been applied in the majority of the analysed clinical trials. An outline of the physiological neurotransmission of the cerebellum is given at the beginning of this article.

CONCLUSION

A systematic search for treatable ataxias is emphasized, as a response to the severity of the degenerative conditions. The use of GABAergic drugs is proposed in ataxias associated with a deficiency of GABA in the brain, and that of glutamatergic agents, for ataxias associated with glutamate deficiency. The use of serotoninergic and cholinergic drugs is ruled out due to insufficient neurochemical evidence. It is proposed that research on remedies for the cerebellar ataxias should be based on either molecular data, or on neurochemical data, in its defect. To this end, the study of animal or experimental models of ataxia, the use of objective methods for the measurement of ataxia, and the recruitment of homogenous study populations, are all recommended.