Inhibition of SERCA pump.

<p>A) Representative recordings of Purkinje neuron EPSC under control conditions (upper left panel), after addition of 2 μM thapsigargin (upper centre panel), and after raising stimulation frequency to 1 Hz for 5 min (upper right panel). Roman numerals refer to time points in 5A (lower panel). Lower panel shows time course of thapsigargin effect on Purkinje neuron EPSC₁ amplitude. Data are mean ± s.e.m. from 6 cells (3 animals). B) Representative recordings of Purkinje neuron EPSC after addition of 2 μM thapsigargin (upper left panel), after addition of 50 mM caffeine in the presence of thapsigargin (upper centre panel), and following 5 min of 1 Hz stimulation (upper right panel). Roman numerals refer to time points in 5B (lower panel). Lower panel shows time course of thapsigargin and caffeine treatment on Purkinje neuron EPSC₁ amplitude. Data are mean ± s.e.m. from 7 cells (4 animals). C) Time course of paired pulse ratio at 0.033 Hz during thapsigargin treatment in the absence (open squares) and presence of caffeine (filled squares).