On 2017 Sep 10, Misha Koksharov commented:

For rapidly changing metabolites (ATP, other nucleotides, etc), capturing their in vivo levels in brain tissues is particularly challenging (Heller HC, 2011, Wilson DF, 2011, Overmyer KA, 2015). They can change in a matter of seconds after the blood flow is interrupted. This unfortunately hampers investigation of many interesting questions (as well as leads to incorrect nucleotide measurements in quite a few papers). :( Hopefully, new techniques will become available and more widespread to overcome this.

On 2017 Sep 10, Misha Koksharov commented:

For rapidly changing metabolites (ATP, other nucleotides, etc), capturing their in vivo levels in brain tissues is particularly challenging (Heller HC, 2011, Wilson DF, 2011, Overmyer KA, 2015). They can change in a matter of seconds after the blood flow is interrupted. This unfortunately hampers investigation of many interesting questions (as well as leads to incorrect nucleotide measurements in quite a few papers). :( Hopefully, new techniques will become available and more widespread to overcome this.