Alpha2-adrenergic agonist clonidine for improving spatial working memory in Parkinson's disease.

Abstract

The loss of dopaminergic cells during Parkinson's disease (PD) produces "frontal"-like impairment in spatial working memory (SWM) and planning functions. This study investigated whether an alpha2-adrenergic agonist, clonidine (0.5 or 2 microg/kg, orally), improves SWM, spatial short-term or spatial recognition memory, and planning functions in PD patients. Clonidine 2 microg/kg decreased errors in SWM, but a lower dose, 0.5 microg/kg, had no effect on performance. Clonidine 0.5 and 2 microg/kg failed to improve the strategy used to solve the SWM test. Clonidine 0.5 and 2 microg/kg had no effect on accuracy of performance in the other tests. These results showed that clonidine improves performance in a test of SWM and that this is not due to improved spatial short-term or spatial recognition memory or planning functions. The authors suggest that stimulation of alpha2-adrenoceptors improves the mnemonic processing required for accurate SWM performance in PD patients.