Figure 7
From: Pro-aggregant Tau impairs mossy fiber plasticity due to structural changes and Ca++ dysregulation
Progressive impairment of Ca ++ regulation in mossy fiber boutons in slices of Tau RDΔ . (a1) The photomicrograph shows a magnification of stratum lucidum in a hippocampal slice culture from a control mouse. The slice was labeled with the Ca++ indicator dye Oregon Green BAPTA-1-AM (OGB-1) at DIV 5. After labeling it was possible to locate “giant” mossy fiber boutons loaded with OGB (white arrow). (a2) After membrane depolarization with high KCl Ca++ is flowing into the bouton (white arrow). The increase of intracellular calcium is false-color coded as indicated on the right column. (b1) Analogue to (a1-2) a bouton (white arrow) in a pro-aggregant slice is depicted before and after (b2) membrane depolarization (white arrow). (c1) At DIV 10 a stronger Ca++ influx in boutons (white arrow) after membrane depolarization (c2) compared to boutons in DIV 5 slices (a1-a2) was observed. (d1) A strong decrease in Ca++ influx after depolarization (d2) is observed in boutons from pro-aggregant TauRDΔ slices compared to control slices at DIV 10. (e) Quantification of maximum intracellular Ca++ increase after high KCl application in mossy fiber boutons from control littermate slices (white column) and from pro-aggregant TauRDΔ slices (red column) at DIV 5. Note that the maximum intracellular Ca++ concentration did not change in comparison to boutons from control littermate DIV 5 slices. (f) Comparison of maximum intracellular Ca++ concentration in boutons from control littermate slices (white column) and from pro-aggregant TauRDΔ slices (red column) at DIV10. At DIV 10 the pro-aggregant TauRDΔ slices show a severe impairment in Ca++ influx after membrane depolarization. Note that the maximum intracellular Ca++ peak in control boutons increases with maturation of slices (compare e and f control). Error bars represent SEM. *** p-value < 0.001.