Cyclic Adenosine Monophosphate in Brain Areas: Microwave Irradiation as a Means of Tissue Fixation
Michael J. Schmidt, Dennis E. Sokoloff, G. Alan Robison · 1971
A 1971 study found that microwave irradiation can rapidly fix rat brain tissue in situ, while decapitation increased cyclic AMP in all brain areas.
Plain English Summary
This 1971 study estimated cyclic adenosine monophosphate (cAMP) in discrete regions of rat brains after the rats were killed by microwave irradiation, tested as a way to fix brain tissue. Amounts were highest in the cerebellum and brainstem, intermediate in the hypothalamus and midbrain, and lowest in the hippocampus and cortex. Whole-brain concentrations in microwaved rats were comparable to those in frozen samples.
Why This Matters
This study was a laboratory technique test rather than an exposure experiment: rats were killed by 30 seconds of microwave irradiation, with death after 3 to 5 seconds, so that brain tissue could be fixed in situ and dissected easily. Whole-brain cAMP in microwaved rats (1.18 nmole/g) was comparable to frozen samples (1.41 nmole/g), and the method suits heat-stable compounds such as cAMP. The authors report that after 20 seconds of exposure (70°C) adenyl cyclase and phosphodiesterase were no longer active. Decapitation increased cAMP in all brain areas, with the cerebellum rising three to four times more than other areas, which the authors say illustrates the hazards of measuring drug effects on cAMP in decapitated animals.
Finding
Microwave irradiation may provide a means of rapidly fixing brain tissue in situ while permitting easy dissection of the brain. In this way artifacts produced by decapitation can be eliminated, and concentrations of heat-stable compounds in the brain can be estimated under conditions which more closely approximate those in vivo.
In their words
“Microwave irradiation may provide a means of rapidly fixing brain tissue in situ while permitting easy dissection of the brain. In this way artifacts produced by decapitation can be eliminated, and concentrations of heat-stable compounds in the brain can be estimated under conditions which more closely approximate those in vivo.”
Figures from the Original Paper
Diagram extracted from the original research document.
Show BibTeX
@article{cyclic_adenosine_monophosphate_in_brain_areas_microwave_irradiation_as_a_means_o_g6939,
author = {Michael J. Schmidt and Dennis E. Sokoloff and G. Alan Robison},
title = {Cyclic Adenosine Monophosphate in Brain Areas: Microwave Irradiation as a Means of Tissue Fixation},
year = {1971},
}