Microwave irradiation as a brain banking tool

I love random reading old papers. They’re like treasure chests into secret knowledge that others might overlook. Here’s one: Guidotti et al 1974, “Focussed microwave radiation: a technique to minimize post mortem changes of cyclic nucleotides, dopa and choline and to preserve brain morphology”.

As a summary, they found that microwave irradiation in rat and mouse brains for 2 seconds led to the total inactivation of the enzymes involved in the regulation of numerous brain metabolites, such as cyclic AMP, cyclic GMP, choline acetyltransferase, and phosphodiesterase. As a result, it allowed for the accurate dissection of different brain nuclei for measurement of the concentrations of a variety of different metabolites in a variety of brain areas.

Rapid inactivation of enzyme activity; https://doi.org/10.1016/0028-3908(74)90061-6

The microwave irradiation method described by Guidotti et al. 1974 was relatively crude, as the authors only described microdissection of brain nuclei. It is unclear whether delicate cellular features such as synapses might also be preserved.

Interestingly, microwave irradiation produced extensive denaturation of proteins throughout the brain. Because since enzymes control metabolism, the inactivation of these enzymes can minimize changes in metabolism.

Microwave radiation could theoretically be combined with other brain preservation methods, such as fixation or cryopreservation, to minimize enzyme-driven autolysis during the procedure. A potential limitation of this method is that microwave heating is limited by the thermal conductivity of the tissue.