Changes Of Brain MGluRla,1,2,After 8Hz 130dB Infrasonic Damage And Effect Of Antagonist MCPG

Infrasound exists in nature and social environment widely, and is one of important constituent parts of environmental and industrial noise. In addition, due to possessing some individual peculiarity, such as long distance spread, difficulty to be detected and defended, infrasound becomes more and more important in some domains like environmental protection, occupation hygiene, military medicine and so on. Because some system and organs?natural frequency is distributed in that of infrasound in living body, such as central nervous system (8A2Hz). When the living body exposed in infrasound, resonance effect generates, and a series change in morphology and function may accrue. Meanwhile, infrasound can act on cell constitution directly, cause the change of bioplasm membrane and metabolism. Moreover, infrasound can also stimulate proprioceptor and visceral receptor, act on corresponding locus in central nervous system indirectly. Therefore, the infrasonic damage is in multitrend and multiplayer way, and the injury of central nervous system is in the first place. The study of infrasound is essential both in war and civilian. At present, the molecular mechanism of infrasound acting on central nervous system is still not clear. Glutamate is the most representative and of highest content neurotransmitter in central nervous system, our studies have already proved that brain injury can lead to excessive release and reabsorption disturbance of glutamate, and result in glutamate accumulating, then produce excitable toxic action, and finally induce multi pathological damages in neurons. The excitable toxic effects of glutamate are produced via activation of receptors that include inotropic and metabotropic glutamate receptors(iGluRs and mGluRs). The iGluRs can lead to the overloading of calcium, and the latter, through the changes of the second message subtances such as phosphoinositide (P1), diacylglycerol (DAG), calmodulin (CaM) and cyclic adenosine monophosphate (cAMP), can cause the degeneration of PT, the releasing of calcium from calcium pooi into the cell soma, overloading of calcium, and then the damages of neurons occur. GluRs can be activated by different pathological stimulation, invoke different reaction. In microdose dialysis study, it was certified that the level of glutamate rose after brain injury or ischemia, although antagonists of iGluRs were used, curative effect was not satisfactory. In recent research work, it has been found Out that the antagonist of the first group mGluRs had an effcet to protect hippocamp neurons from damage in vitro. We have proved in past that the structure of brain-blood-barrier could be damaged by infrasound in rats. Because glutamate is the most abundant excitatory amino acid in brain, we presume that brain injury by infrasound may relate to the level of glutamate and the activity of mGluRs, thus, we intend to investigate the changes of mGluRla, 1, 2 subtypes and the effect competitive antagonist c- methyl-4-carboxyphenylglycine (MCPG) by immunohistochemistry, in situ hybridization, pathological and ultrastructure morphological methods, in order to probe into the role of glutamate and mGluRs in brain injury, offer experimental and theoretical foundation for biological therapy of infrasound. It is showed that compared with the control group, The number and the A value density of mGluRla,1 positive neurons increased after 1-time infrasonic damage(PO.05), mGluRla had a similar patt...