FIGURE 5.

Uptake of 5′-AMP by erythrocytes and increased deoxyhemoglobin levels. a, uptake of radiolabeled [¹⁴C]adenosine or 5′-[¹⁴C]AMP by isolated erythrocytes in vitro. Autoradiograph showing the TLC analysis of erythrocyte extracts compared with known radiolabeled purine standards. Shown are representative HPLC chromatograms of purine products extracted from blood obtained from mice in euthermia (b), in spontaneous arousal (c), and during DH (d) and an animal in DH given a second injection of 0.5 mg/g 5′-AMP and sacrificed 2 h later (e). HPLC of purine standards was used to determine the identity of the various peaks. f, absorbance spectrum of whole blood from mice (n = 2) treated with 5′-AMP (dashed lines) or untreated (solid lines). Blood was taken 10 min after intraperitoneal administration of 5′-AMP (0.5 mg/g).