Neostigmine influences the L-dopa-induced extracellular dopamine levels inthe striatum

Using in vivo microdialysis in freely moving rats, we show that the additio n to the dialysis perfusion fluid of the acetylcholinesterase inhibitor neo stigmine influences the decarboxylation of levodopa (L-dopa). Continuous pe l fusion of neostigmine (10, 50 and 100 nM) in striatum attenuated the L-do pa-induced dopamine release in a doss-dependent manner. This effect suggest s that changes in magnitude of drug responses may occur when an acetylcholi nesterase inhibitor is included in the perfusion solution. Results obtained under these circumstances should be carefully interpreted concerning the p harmacological effects of other drugs when used concomitantly with neostigm ine. (C) 2000 Elsevier Science B.V. All rights reserved.