Characterization of Real Time Adenosine Effluxes in the Brain of Anesthetized Rats using Fast‐Scan Cyclic Voltammetry

Abstract

The present study was designed to characterize adenosine effluxes in the brain using fast scan cyclic voltammetry and explore how spontaneous adenosine release may be affected by a tail pinch. Long Evans rats were anesthetized and a carbon fiber electrode was positioned in the motor cortex or dorsal striatum. Voltammetric recordings were made every 100 ms by applying a triangular waveform from ‐0.4 to +1.5 V and back versus an Ag/AgCl reference electrode at a rate of 400 V/s. Frequency of adenosine spikes detected was relatively stable in both tested regions and the time intervals between spikes were regular and lasted from 1 to 6 seconds. The number of spikes per 10 seconds ranged from 7.5 ± 0.56 to 9.5 ± 0.62 in the motor cortex and 8.0 ± 1.24 to 9.8 ± 1.54 in the dorsal striatum. The average amplitude fluctuated from 75.0 ± 10.18 to 94.3 ± 18.12 nM in the motor cortex and from 122.7 ± 29.17 to 150.3 ± 43.20 nM in the dorsal striatum. Statistical analysis did not reveal any significant difference in the frequency or the amplitude between the two regions (n=6 rats, p>0.05). The striatal and cortical clearance rate of adenosine was equivalent (n=7 rats, 137.4 ± 23.23 and 195.9 ± 44.14 nM/s for the cortex and striatum, respectively). Furthermore, a 3 s tail pinch transiently increased adenosine signaling in both brain areas. The increase was significantly higher in the dorsal striatum than the motor cortex (n=6, p<0.05). Our study confirmed that adenosine signaling can operate on a faster time scale to modulate brain functions. This study was supported by NIAAA R01AA022449.