Application of high-powered microwave irradiation for acetylcholine analysis in mouse brain

Effects of Radiofrequency Electromagnetic Radiation on Neurotransmitters in the Brain

With the rapid development of electronic information in the past 30 years, technical achievements based on electromagnetism have been widely used in various fields pertaining to human production and life. Consequently, electromagnetic radiation (EMR) has become a substantial new pollution source in modern civilization. The biological effects of EMR have attracted considerable attention worldwide. The possible interaction of EMR with human organs, especially the brain, is currently where the most attention is focused. Many studies have shown that the nervous system is an important target organ system sensitive to EMR. In recent years, an increasing number of studies have focused on the neurobiological effects of EMR, including the metabolism and transport of neurotransmitters. As messengers of synaptic transmission, neurotransmitters play critical roles in cognitive and emotional behavior. Here, the effects of EMR on the metabolism and receptors of neurotransmitters in the brain are summarized.

Separation and quantification of choline and acetylcholine by thermospray liquid chromatography/mass spectrometry

The development of sensitive analytical techniques for use in the identification and qualification of molecules of biological origin remains a constant challenge. Often the compounds of interest are present in a complex mixture and require extensive sample preparation prior to analysis. Thermospray liquid chromatography/mass spectrometry (LC/MS) has been shown to be a method which allows for both separation of target molecules from complex mixtures and sensitive specific detection using a mass spectrometer. In this work thermospray LC/MS is used for the direct detection of intact, underivatized choline and acetylcholine from mouse brain homogenate. The results of our analysis corroborate previous analyses using a variety of indirect measurement techniques and thereby show that this simple direct analysis has wide potential applicability.

Microwave irradiation as a form of fixation for light and electron microscopy

Microwave irradiation was used to fix a wide range of surgical and autopsy specimens as well as tissue from freshly killed rats. Although there appeared to be varying optimum temperatures of fixation for different tissues, from a practical standpoint, the heating to 58 degrees C of tissues submerged in normal saline resulted in fixation of a quality comparable with that produced by conventional fixation to 10 per cent formalin. Microwave irradiation applied to tissues which had up to 1 h prior immersion in 10 per cent formalin also produced excellent preservation of cytomorphology, the time required for microwave fixation being no more than 150 s. This form of rapid heat fixation had no deleterious effects on special stains, sectioned as well as control fixed blocks and produced less shrinkage artefact than conventional formalin fixation. Immunocytochemical staining for more stable cytoplasmic antigens revealed no significant difference between microwave fixation compared with formalin fixation. The more labile membrane associated antigens of lymphocytes, however, were not preserved by either method of fixation. Microwave fixation was also found to be applicable to electron microscopy. Tissue samples immersed in 2.5 per cent glutaraldehyde and fixed in 90 s by irradiation to 50 degrees C showed excellent preservation of ultrastructural morphology.

Development and use of a nonrestraining waveguide chamber for rapid microwave radiation killing of the mouse and neonate rat

The use of microwave energy for rapid killing of small rodents such as the mouse or rat has become a standard pharmacologic technique since approximately 1975. This method allows investigation of rapidly modulated neurochemical indices, neuromodulatory substances, and some neurotransmitters to be determined at basal concentrations in brain regions and microregions. Previously described devices for use with microwave generators have relied on total body restraining holders in order to properly position rodents and neonates within a closed waveguide during microwave energy exposures. The present information describes two alternate chamber designs which do not require restraint of the rodent. A positioning device is described which must be used with the waveguide chambers. The animal chambers are designed to be used with 2450 MHz energy.

Plasma and red cell volumes of microwave irradiated mice tissues

A double isotope technique was applied to the microwave irradiation of mice for reliable measurement of the distribution of red cells and plasma. Microwaves provide a means for rapid cessation of circulation. Hematocrit values of blood in minute tissue samples can be estimated. The red cell and plasma volumes as well as the hematocrit values of the liver, kidney, spleen, intestine, lung and brain tissues of mice are presented. A biological filtration of technetium labelled red cells is necessary for their physiological distribution in circulation.