Figure 1
Purinergic enhancement of ciliary beat frequency is observed in both P2X 7 +/+ and P2X 7 -/- mice. (A) DIC image of an ependymal cell. (Bar = 12 μm) Cilia are noted (*). (B) Beat frequency (normalized) during 300 μM BzATP application in slices from P2X7+/+ (filled circles/solid line; n = 5) and P2X7-/- (open squares/dotted line; n = 4) mice. Responses from P2X7+/+ and P2X7-/- animals were not significantly different. (C) Beat frequency (% increase) in slices from P2X7+/+ (n = 5) and P2X7-/- (n = 4) mice after 5 min 300 μM BzATP application. Decreases (P < 0.05) were observed in the presence of the ecto-5'-nucleotidase inhibitor αβmADP (50 μM) in P2X7+/+ (n = 6) and P2X7-/- (n = 6) mice. BBG significantly decreased BzATP-induced enhancement in P2X7+/+ mice (n = 4). (D) Beat frequency (% increase) in P2X7+/+ mice during application of 100 μM ATP (P < 0.05 compared to no drug control; n = 4). The P2Y receptor antagonist suramin (200 μM; n = 5) did not significantly reduce enhancement seen with 100 μM ATP. Beat frequency was not enhanced by the P2Y2/P2Y4 agonist UTP (100 μM; n = 2). (E) Beat frequency enhancement with increasing concentrations of adenosine (filled circles; n = 4-5) and NECA (open squares; n = 4-8). A significant difference was observed between NECA and adenosine at 1 μM. *: P < 0.05 for all panels, data are means ± SEM. The n value indicates number of slices tested.