High sensitivity measurement of brain catechols and indoles in vivo using electrochemically treated carbon-fiber electrodes.

The combination of electrochemically treated carbon-fiber electrodes with DPV, DNPV or DPA represents a wide range of possibilities. As shown in this review, the choice of treatment and measurement technique depends on the purpose. As regards in vivo monitoring of 5-HIAA or DOPAC from very small brain nuclei, electrochemically treated carbon-fiber electrodes appear very potent and inexpensive. The main limitation of the established electrochemical techniques, including those discussed here, is that the unequivocal measurement of the basal extracellular neurotransmitter level cannot be achieved unless animals are treated with pargyline. On the other hand, this monitoring is feasible with in vivo dialysis. Therefore, electrochemical techniques, on the one hand, and in vivo dialysis, on the other hand, present different advantages. The former are much more potent than the latter in two respects. First, due to the much smaller size of the sensor, electrochemical techniques are more suitable for studying small brain nuclei. Second, since electrochemical techniques exhibit a better temporal resolution, they are recommended for investigating the relationship between impulse flow and neurotransmitter release. However, when high anatomical or temporal resolution is not required, in vivo dialysis is more suitable for recording the basal monoamine release.