I recently performed some experiments where one of the stimulants elicited calcium oscillations in cultured astrocytes. However, even though all of them are oscillatory, the oscillation pattern of even two cells in the same field of view is not the same. Some cells show high frequency oscillations, some with late oscillatory periods and some with sustained Ca2+ rise/ shoulder. Any suggestions as to why cells in the same culture conditions evoke different patterns of Ca2+ oscillations when stimulated by the same stimuli at once? Is it due to the intrinsic biophysical state of each of these cells or something else?
Hi,
it is very common to observe such variability in calcium oscillations pattern amongst cells from the same cultures/plates/field of views, especially when using primary cultures. There are as many reasons as you can think of to explain this: intrinsic biophysical or biochemical state of the cells (for example, phosphorylation state of key components of the signaling pathway), or which phase of the cell cycle the cells are in, whether some cells are apoptotic, even whether all the cells are similar or not (neural cultures are a bit heterogeneous)...
The analysis of the experiments should therefore include these parameters: are treatments (or whatever you are doing to you cells) shifting the population response towards more/less high frequency oscillations, towards only sustained responses? Are they increasing frequency, amplitude of the responses? There is a lot of literature out there about calcium oscillations in neural tissue and starting with Berridge MJ and Spitzer NC is a safe choice. You can also check this review that we published on the subject: http://www.ncbi.nlm.nih.gov/pubmed/20494106.
Experimentally, one should include a positive control at the end of your experiment in order to filter out cells that are not responding properly to a known stimulus. Also, and as a general rule, calcium experiments should be performed on rather large numbers of cells&cultures to be able to draw conclusions based on population analysis, and to .
Hope it helps & good luck!
Great ... thanks a lot for that... just one more question. In one of the cells, there was a sustained Ca2+ rise for 36 seconds before falling to mid level (compared to its original baseline) where it started giving oscillations. As literature suggests that Calcium oscillations lead to glutamate release, what would this sustained Ca2+ increase might lead to? A sustained release of excessive glutamate (hypothetically)?
- Badges
- Science topic