Fig. 1.

ATP concentration–response relationship for the intrarenal pre- and postglomerular vascular segments. Average segmental diameter responses evoked by ATP applied to the adventitial surface of arcuate arteries (top panel), interlobular arteries (second panel), afferent arterioles (third panel) and efferent arterioles (bottom panel). After the control period (Con), increasing concentrations of ATP (0.1, 1.0, 10 and 100 µM) were applied at 5-min intervals as indicated by the dotted lines. Each protocol ended with a 5-min recovery period (Rec) while bathed with control solution. Each data point represents diameter measurements taken at 12-s intervals and normalised as a percentage of the control diameter. Data were modified from an earlier report [21]