Calciotropic hormones as possible modulators of rat extrapyramidal motor system.

In the present study the Authors have investigated the effects of chronic treatment with calcitonin and parathyroid hormone on rat extrapyramidal motor system. Although it seems that calcitonin and parathyroid hormone may act as a neuromodulators at extrapyramidal level by influencing, directly or indirectly, nigro-striatal dopaminergic transmission, the role played by calcium metabolism at peripheral level, is not clear. In order to put light on this matter, different groups of animals were treated with calciotropic hormones plus EDTA, which is a drug that blocks Ca2+ ions, or EDTA alone. The results obtained don't show any change either in nigral GAD activity or apomorphine induced hyperactivity in EDTA injected animals. Furthermore, EDTA doesn't seem to modify the effects of both PTH and ct, as shown by results obtained in animals treated with ct or PTH plus EDTA.