Figure 7.

Block of SERCA by thapsigargin abolishes the observed changes in slow AHP, Ca²⁺ signaling, and Ca²⁺ buffering in Prnp^0/0 neurons. To examine the role of the ER in buffering, the added buffer experiments were repeated in neurons that were either under control conditions (Tg naive) or pretreated with thapsigargin (3 μm). A, In Prnp^0/0 neurons, the reduction in both slow AHP (Ai, light gray traces) and Ca²⁺ signaling (Aii, light gray traces) was abolished by pretreatment with thapsigargin (3 μm; Ai, Aii, dark gray traces). B, C, Concomitant with these changes, the increase in the buffering capacity was also abolished. Buffering capacity was estimated from the inverse amplitude because blockade of SERCA alters Ca²⁺ decay kinetics. p < 0.005.