Application of Multi-Dimensional Liquid Chromatography (NEUBA®) to the Determination of Neuronal Changes in an Organism
A very large number of neurochemical investigations incorporate sacrificing as a precursor to the measurement of various neurochemicals following psychological, pharmacological, or behavioral paradigms. The vast majority of such investigations to date have employed either decapitation or cervical dislocation as the primary means of sacrifice. However, such approaches to the examination of CNS mechanisms in mammalian systems suffer quite seriously from a rapid post mortem alteration in the levels of the compounds to be determined. Two separate solutions to this problem have been put forward by various research groups. The first involves rapid freezing of the tissue of concern, thereby inactivating the enzymes associated with the post mortem alteration (Veech et al,1973). In this approach, one rapidly ejects the CNS tissue from the skull cavity such that it impacts on a plate held at liquid nitrogen temperatures. This rapidly lowers the temperature of the tissue, but, unfortunately, does not allow for easy identification of individual brain regions. Alternatively, one could simply freeze the brain by dropping a decapitated head immediately into liquid nitrogen. This second approach, which allows for reasonable dissection, is not accomplished on as rapid a time scale. In short, both approaches to freezing suffer from some serious deficiencies. Additionally, when frozen tissue is subjected to subsequent homogenization, as is done in almost all procedures, the temporarily inactivated enzymes resume their activity and continue to alter the levels of the compounds which one is attempting to measure. Thus, it appears that the second approach to cessation of rapid post mortem metabolism is more appropriate. In this case, one sacrifices the animal and simultaneously
KeywordsMicrowave Irradiation Brain Temperature Brain Tissue Sample Rapid Inactivation Brain Enzyme
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