Fig. 4. Apyrase, oATP and BBG prevent ATP effects on individual cholinergic neurons in isolated retinas. (A,B) A P4 rat cholinergic cell before (A; cell soma in the inset) and 30 minutes after (B) application of 1 mM ATP. ATP induces extensive blebbing in the dendrites and soma (bottom inset in B), and permeability to PI (top inset in B). (C,D) A P5 rat cholinergic cell before (C, soma in inset), and 30 minutes after (D) application of 1 mM ATP in the presence of apyrase (30 U/ml). Apyrase totally prevented dendritic and somal blebbing (bottom inset in D), as well as PI permeability (top inset in D). (E,F) A P3 rat cholinergic cell preincubated with oATP (300 µM, 2 hours preincubation) is shown before (E) and 30 minutes after application of 1 mM ATP. Preincubation with oATP totally prevented dendritic and somal blebbing (bottom inset in F), as well as PI permeability (top inset in F). (G-I) A P5 rat cholinergic cell is shown just before (G, cell soma in the inset) and 30 minutes after (H) application of 1 mM ATP in the presence of 0.2 µM BBG. No blebbing is observed in the dendrites (H) or in the cell soma (bottom inset in H), nor was the cell permeable to PI (top inset in H; red dot is the gene gun bullet). The protective effect of BBG was reversible: after 10 minutes washing to remove BBG, application of 1 mM ATP induced blebbing of the cell dendrites (I) and soma (bottom inset in I), as well as cell permeability to PI (top inset in I) within 30 minutes. Scale bar: 15 µm (A-F); 8 µm (insets in A-F); 20 µm (G-I); 10 µm (insets in G-I).