Fig. 9.

Inhibition of nucleoside transport enhances the extracellular accumulation of adenosine during ischaemia. (a) Combined application of the transport inhibitors dipyridamole (DIPY, 10 μmol/L) and NBTI (5 μmol/L) resulted in a slowly developing inhibition of the fEPSP which coincided with a slowly increasing signal on the Ado/ino sensor, demonstrating that the transport inhibitors were effective in raising extracellular adenosine levels. Magnified examples of the fEPSP are shown taken before (i) and during (ii and iii) the application of NBTI/DIPY at the times indicated. (b) Prolonged incubation with DIPY/NBTI did not prevent release of adenosine during ischaemia (black bar). Instead ado/ino release was enhanced, whilst there was little apparent effect on ATP release. The equilibrative nucleoside transporters are thus highly unlikely to mediate the release of adenosine during ischaemia.