RECENT ADVANCES IN IN VIVO ELECTROCHEMISTRY

Since its introduction, the major goal of in vivo electrochemistry has been to provide researchers with a means of monitoring extracellular fluxes of the biogenic amine neurotransmitters and related species in the brains of small laboratory animals. The basic concepts behind the measurements are very simple; however, there are numerous details which in many cases have not been thoroughly explained. Some of these are: (1) choice of the electrochemical working electrode; (2) choice of the electrochemical method; (3) instrumentation; (4) mass transport of species to the tips of the recording electrodes; (5) microdelivery of drugs and materials to the recording electrodes; and (6) recording electrode selectivity and sensitivity in brain tissue.;Another major emphasis involved the determination of the diffusion properties of the biogenic amine neurotransmitters and related species. A new flow injection analysis (FIA) procedure is introduced for the accurate determination of solution diffusion coefficients. Also explored is an electrochemical method for determining the diffusion rates of species in brain tissue.;Associated with problems of electrode selectivity in brain tissue has been work reported on a new type of polymer-coated electrode. This electrode is termed a Nafion-coated GEC and responds selectively to only the cationic neurotransmitters (i.e., DA and NE) and minimally to anionic species or neutrals such as ascorbic acid or DOPEG.;The dissertation also includes an appendix on electro-analytical studies of phencyclidine (PCP) and several appendices associated with the design and implementation of in vivo electrochemistry instrumentation.;It has been the purpose of this dissertation to fill in some of the details for performing in vivo electrochemistry experiments. A major emphasis has been to present the design, construction and evaluation of a multiple microcomputer system for performing these measurements. This system is highly automated and capable of simultaneously recording from up to four discrete brain regions in two different animals. Also represented is the design and development of suitable inexpensive equipment for the beginning in vivo electrochemistry laboratory.