Module 6: Figure pancreatic Ca2+ oscillations
Oscillations of Ca2+ in the endoplasmic reticulum (ER) lumen of pancreatic acinar cells.
The Ca2+ oscillations were recorded indirectly by monitoring the Cl− current (I), which is the black trace and is inverted. Each downward deflection reflects an increase in the intracellular level of Ca2+. Upon addition of 100 nM acetylcholine (ACh), the level of Ca2+ began to oscillate. Note how each Ca2+ transient resulted in a small decrease in the level of Ca2+ within the lumen of the endoplasmic reticulum (ER) (red trace). It is clear that each transient caused a small depletion, because upon addition of a larger concentration of Ach, there was a much larger release of Ca2+ and a corresponding large fall in the level of luminal Ca2+ ([Ca2+]Lu]. Reproduced by permission from Macmillan Publishers Ltd: EMBO J. Park, M.K., Petersen, O.H. and Tepikin, A.V. (2000) The endoplasmic reticulum as one continuous Ca2+ pool: visualization of rapid Ca2+ movements and equilibration. 19:5729–5739. Copyright (2000); http://www.embojournal.org; see Park et al. 2000).