Diffusion of radiolabeled dopamine, its metabolites and mannitol in the rat striatum studied by dual-probe microdialysis

Abstract

Publisher Summary The intra cerebral dual-probe microdialysis technique allows the study of diffusion of labeled molecules in vivo in anaesthetized or awake animals. The labeled markers can be biologically inert molecules or endogenous substances delivered and sampled without any volume changes or other disturbances to brain homeostasis. This chapter discusses the experiments in which diffusion of radio labeled dopamine (DA), its metabolites and mannitol in the rat striatum studied by dual-probe microdialysis. In view of data reported in the chapter, it is hypothesized that the infusion of 3H-DA into the DA, denervated rat striatum may cause an immediate increase of local CBF and capillary permeability augmenting the clearance processes of extacellular 3H-DA and its metabolites as manifested by their reduced extracellular levels and the inability to measure the long-distance diffusion of 3H-DA. Infusion of 3Hmannitol, on the other hand, may not affect cerebral blood flow or capillary permeability, and consequently no differences at steady state were observed in control and lesioned animals. These results provide new insights into DA volume transmission in the DA denervated striatum and thus in the striatum of Parkinson disease patients.