Analysis of amino acids and catecholamines, 5-hydroxytryptamine and their metabolites in brain areas in the rat using in vivo microdialysis

In vivo microdialysis, using dialysis probes inserted into discrete brain a reas and subsequent analysis of neurotransmitters and related substances in the dialysates (usually with HPLC), has yielded a great deal of important information about the actions of psychotropic drugs and endogenous neurotra nsmitter systems and about the functional interactions between various brai n areas. This paper reviews the principles involved in in vivo microdialysi s, its advantages and disadvantages, and recent innovations in methodology and applications. The first section includes brief discussions of principle s and applications of dialysis, use of anesthetized versus conscious freely moving animals, and methods used to determine the neural origin of neurotr ansmitters in the dialysate. The subsequent sections provide detailed descr iptions, based largely on our own studies in rats, of stereotaxic surgery, in vivo microdialysis, and dialysate analysis, with an emphasis on amino ac ids and biogenic amines and their metabolites. A discussion of methodologic al problems which may be encountered in the analysis of amino acids and bio genic amines is also included. (C) 2001 Academic Press.