There are slight differences in many formulations, eg., some people use 1 mL extra of MgCl to block NMDA receptors.
Some use 125 mM NaCl.
Obviously we have HCO3/NaHCO3
20-25 mM Glucose
2.5mM KCl
I was wondering what different formulations did people use, and why?
And I also wanted to see if there were major differences in these formulations.
There have been more than a few studies that have tried to look at how varying aCSF content can affect slice viability. See here for a discussion:
http://www.ncbi.nlm.nih.gov/pubmed/7475244
In particular, slices from older animals seem more susceptible to factors such as hypoxic stress and the osmolarity of the aCSF (see Moyer and Brown J Neurosci Meth 86:35-54, 1998).
There is also literature to suggest that HEPES buffering may be preferred to reduce edema within brain slices.
I think that most labs develop protocols based on what yields the most viable slices for recording, and then make modifications depending on what is needed. So there is not necessarily a "best" solution, but depending on the experiment and the brain region of interest, some slight modifications to the basic buffer might prove useful.
Thank you, that was very helpful. Many people I've met consider it a voodoo ritual, no specific idea behind their formulation.
I agree with Alexander about the 2 references he pointed out. These were very helpful to me. In addition, you may be interested in these studies:
•Tanaka, Y., et al. (2008) The effects of cutting solutions on the viability of GABAergic interneurons in cerebral cortical slices of adult mice. J Neurosci Methods. 171, 118-125.
•Aghajanian, G.K., and Rasmussen, K. (1989) Intracellular studies in the facial nucleus illustrating a simple new method for obtaining viable motoneurons in adult rat brain slices. Synapse. 3, 331-338.
•Ye, J.H., et al. (2006) Patch-clamp studies in the CNS illustrate a simple new method for obtaining viable neurons in rat brain slices: glycerol replacement of NaCl protects CNS neurons. J Neurosci Methods. 158, 251-259.
•Richerson, G.B., and Messer, C. (1995) Effect of composition of experimental solutions on neuronal survival during rat brain slicing. Exp Neurol. 131, 133-143.
•Bischofberger, J., et al. (2006) Patch-clamp recording from mossy fiber terminals in hippocampal slices. Nat Protoc. 1, 2075-2081.
•MacGregor et al, (2001) HEPES prevents edema in rat brain slices. Neuroscience Letters. 303(3):141-4.
•Brahma et al, (2000) Ascorbate inhibits edema in brain slices. J Neurochemistry. 74(3):1263-70.
If you are especially interested in modified aCSF recipes and acute brain slices from adult animals you may like to see the website I developed on this topic. There is a downloadable excel file with various modified aCSF recipes we have used with success. (www.brainslicemethods.com)
How important are glucose levels? I note 20-25 mM is mentioned in the question. Is CSF closer to 1 mM?
Does CSF glucose concentration vary between species?
https://biochemazone.com/product/artificial-cerebrospinal-solution-bz178/
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