Characterizing Spontaneous Transient Adenosine Release

Adenosine is an important neuromodulator that regulates numerous physiological processes such as blood flow, heart rate, and neurotransmission. Traditionally, adenosine has been thought to act in a slow manner, accumulating in the extracellular space after major events such as ischemia [1]. Previous methods to study adenosine release, such as radio-labeled HPLC had good sensitivity and selectivity, but temporal resolution only on the minute time scale [2]. Our lab has demonstrated that adenosine can be quantitated on the millisecond time scale with fast-scan cyclic voltammetry (FSCV) at carbon-fiber microelectrodes [3]. We have characterized stimulated adenosine release [4] and also we recently discovered spontaneous transient adenosine release. In this study, we have characterized spontaneous transient adenosine release in the caudate putamen and prefrontal cortex of anesthetized rats. We hypothesized that adenosine transients were modulated by A1 receptors; however, DPCPX, an A1 receptor antagonist, did not affect adenosine transient release. The discovery of rapid adenosine signaling shows that adenosine has both slow and fast time scales of action. Characterizing rapid adenosine signaling will lead to a better understanding of how rapid adenosine modulates blood flow and neurotransmission.