Correlation of transient adenosine release and oxygen changes in the caudate-putamen.
Adenosine is an endogenous nucleoside that modulates important physiological processes, such as vasodilation, in the central nervous system. A rapid, 2-4 s, mode of adenosine signaling has been recently discovered, but the relationship between this type of adenosine and blood flow change has not been characterized. In this study, adenosine and oxygen changes were simultaneously measured using fast-scan cyclic voltammetry. Oxygen changes occur when there is an increase in local cerebral blood flow and thus are a measure of vasodilation. About 34% of adenosine transients in the rat caudate-putamen are correlated with a subsequent transient change in oxygen. The amount of oxygen was correlated with the concentration of adenosine release and larger adenosine transients (over 0.4 μM) always had subsequent oxygen changes. The average duration of adenosine and oxygen transients was 3.2 and 3.5 s, respectively. On average, the adenosine release starts and peaks 0.2 s prior to the oxygen. The A2aantagonist, SCH442416, decreased the number of both adenosine and oxygen transient events by about 32%. However, the A1antagonist, DPCPX, did not significantly affect simultaneous adenosine and oxygen release. The nitric oxide (NO) synthase inhibitor l-NAME also did not affect the concentration or number of adenosine and oxygen release events. These results demonstrate that both adenosine and oxygen release are modulated via A2areceptors. The correlation of transient concentrations, time delay between adenosine and oxygen peaks, and effect of A2areceptors suggests that adenosine modulates blood flow on a rapid, sub-second time scale. Read the Editorial Highlight for this article on page 10.
Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA.
Ying
Y
Wang
Department of Chemistry, University of Virginia, Charlottesville, Virginia, USA.
B Jill
BJ
Venton
D000241:Adenosine / Q000378:metabolism*; D000818:Animals; D002421:Caudate Nucleus / Q000378:metabolism*; D008297:Male; D008839:Microelectrodes; D010100:Oxygen / Q000378:metabolism*; D011699:Putamen / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D000241:Adenosine; D010100:Oxygen

FSCV
; 
in vivo
; adenosine; blood flow; fast-scan cyclic voltammetry; oxygen