Estimation of in-vivo neurotransmitter release by brain microdialysis: the issue of validity.

摘要: Although microdialysis is commonly understood as a method of sampling low molecular weight compounds in the extracellular compartment tissues, this definition appears insufficient to specifically describe brain neurotransmitters. In fact, transmitter overflow from into dialysates critically dependent upon composition perfusing Ringer. Therefore, dialysing Ringer not only recovers fluid but main determinant its in-vivo release. Two types are distinguished: quantitative micro-dialysis and conventional microdialysis. Quantitative provides an estimate neurotransmitter concentrations contact with probe. However, information might poorly reflect kinetics release vivo. Conventional involves perfusion at constant rate transmitter-free Ringer, resulting formation steep concentration gradient extending fluid. This artificial be critical for ability detect resolve phasic changes taking place implanted area. On basis these characteristics, neurotransmitters can conceptualized model brain. As such, criteria face-validity, construct-validity predictive-validity should applied select most appropriate experimental conditions estimating specific areas relation behaviour.