Prior to analyses of
- Cyclic AMP
- Cyclic GMP
- Catecholamines and their metabolites
- Phosphorylated Proteins
In neurochemical studies of the brain, it is of great importance to accurately measure neurochemical events in vivo. However, it is difficult to perform reproducible and meaningful measurement of these events because rapid post-mortem changes occur in the brain concentrations of several metabolites and some neurotransmitters.
Therefore, various techniques have been developed to prevent post-mortem changes. One of the more common method is cooling or freezing by immersion of the living animal and the decapitated head in liquid Nitrogen or cooled Freon to inactivate enzymes involved in the metabolism of these compounds. Although cooling is frequently used in many laboratories, it is not fully effective in preventing post-mortem changes. The time required to freeze deep structure of the brain may range from 10 – 90 seconds due to the poor thermal conductivity of tissues surrounding the brain; post-mortem changes will occur during this period.
An alternate method is microwave heating to inactivate enzymes. The method has several advantages over cooling or freezing :
If microwave power of sufficient level is focused on the animal’s head, the enzymes in the whole brain can be completely inactivated in a very short time. Further,the brain can be dissected easily and reproducibly at room temperature.
Therefore, microwave irradiation system is quite useful when measuring Acetylcholine, Choline, Cyclic AMP, Cyclic GMP, GABA, DOPA, 5-HTP, Serotonin, Endorphin, Prostaglandin, Catecholamines and their metabolites in the brain and so forth.