Second-by-second measures of l-glutamate and other neurotransmitters using enzyme-based microelectrode arrays

L-Glutamate is the major excitatory neurotransmitter in the mammalian central nervous system (CNS) and is implicated in a number of brain disorders including Parkinson’s disease (PD), cognitive disturbances, epilepsy, schizophrenia, attention deficit hyperactivity disorder (ADHD) and drug abuse. While microdialysis methods have been used extensively over the last decade to investigate minute-by-minute measures of L-glutamate, the rapid time dynamics of L-glutamate signaling in the CNS has warranted a technique to measure L-glutamate release on a secondby- second basis. A major goal of the research is to develop a recording technology for recording second-by-second measurements of L-glutamate and other neurotransmitters-specifically a mass-fabricated microelectrode technology that could be (1) mass produced such that other laboratories could utilize the same recording technology and (2) configured for “self-referencing” recordings, which allows for second-by-second cross-checking of the selectivity of the microelectrode measures and improved signal-to-noise of the recording methods. The present chapter documents current capabilities of measuring L-glutamate and several other neurotransmitters on a second-by-second basis using mass-fabricated microelectrode arrays formed on ceramic. While not a comprehensive assessment of the technology, this chapter contains a large amount of information regarding the fabrication, use, and potential pitfalls of this technology. The reader should refer to numerous articles1-6 for additional details regarding measuring neurotransmitters in the CNS.