Fig. 1.

A: rat preglomerular vascular smooth muscle cells were incubated for 1 h with various concentrations of adenosine (0, 0.3, 1, or 3 μmol/l) plus various concentrations of guanosine (0, 10, or 30 μmol/l). B: rat preglomerular vascular smooth muscle cells were incubated with adenosine (3 μmol/l) for 1 h in the absence (control) or presence of guanosine (30 μmol/l), guanosine 5′-monophosphate (GMP; 30 μmol/l), or GMP plus α,β-methylene-adenosine-5′-diphosphate (AMPCP; 100 μmol/l). For A and B, the medium was assayed for adenosine by mass spectrometry. Values represent means ± SE. <DL, less than detection limit.