Alpha Omega Alpha Honor Medical Society

2014 Research Abstract

Real-Time Detection of Extracellular Adenosine Using Enzyme-linked Microelectrode Arrays

Investigator: Justin Gibson, University of Cincinnati College of Medicine

Mentor: Jed Hartings, PhD

ABSTRACT
Increases in extracellular adenosine serve important neuroprotective and neuromodulatory functions, via activation of A1 and A2 receptors, throughout the central nervous system. However, current understanding of the in vivo mechanisms regulating extracellular adenosine at level of the neurovascular unit is limited by a lack of techniques with sufficient spatial and temporal resolution. Here, we describe the performance of self-referenced enzyme-linked microelectrode arrays (MEAs) to selectively measure extracellular adenosine with high spatial (7500 µm2) and temporal (4 Hz) resolution. In vitro the MEAs were able to detect low levels of adenosine (limit of detection 0.96 ±0.1µM) and responded to sequential additions of adenosine in linear fashion (slope = 40.2 ± 7.7 pA/ µM , r2 = 0.98 ± 0.0), permitting in vivo determination of basal concentrations of extracellular adenosine. In vivo local applications produced transient increases in the extracellular concentration that were dose-dependent (200 nL: 6.8 ± 0.6 µM; 400 nL: 19.4 ± 2.2 µM) [t(13) = 6.6, P < 0.001]. Furthermore, local injection of dipyridamole, which inhibits transport of adenosine through equilibrative nucleoside transporter, raised the extracellular concentration of adenosine by 120% (5.6→12.3 µM) [t(16) = 8.0, P < 0.001] demonstrating the MEAs are capable of detecting endogenous sources of extracellular adenosine with adequate temporal and spatial resolution to study the intrinsic mechanisms regulating the extracellular concentration.

Last modified: 5/29/2015

Updated on May 29, 2015.


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