Abstract

Microdialysis (MD) is an in vivo bioanalytical sampling method used in both animals and humans to determine physiological and chemical substances in tissues and organs. “Micro” refers to the extremely small scale and “dialysis” refers to the movement of chemicals across a permeable membrane. MD provides a preview of what goes on in tissues, before chemical events can be reflected as changes in systemic blood levels. This method was designed for the first time in the late 1950s to study endogenous compounds in the animal brain. It has been developed for use in other organs over the years. In this in vivo method, sampling from almost any tissue, organ or biological fluid reflects the composition of the extracellular fluid. Using specially designed probes, unbound analytes are continuously sampled continuously. These may include endogenous molecules (e.g. neurotransmitters, hormones, glucose) sampled to assess their biochemical functions or exogenous compounds (e.g. pharmaceuticals) sampled to determine their distribution within the animal. Local effects of exogenous compounds have been studied in the central nervous system, hepatic tissue, dermis, heart and corpora luteae of experimental animals by means of microdialysis. Furthermore in central nervous studies, this technique has been extensively used for the study of the effects on neurotransmission at different central nuclei of diverse pharmacological and toxicological agents, such as antidepressants, antipsychotics, antiparkinsonians, hallucinogens, drugs of abuse and experimental drugs. MD is widely used today in many fields including biomedical research. The aim of this review is to define the basic principles of microdialysis, to indicate its application areas to reveal its advantages and disadvantages and to emphasize its importance in clinical pharmacology and toxicology research.