Awake Rat Neurotransmitters And Eeg Detection Methods In The Study Of The Sedative Mechanism

Neuroelectrophysiological and neurochemical signals are of great significance to various physiological and pathological phenomena. Researchers had studied these two different systems separately for many years. The development of microdialysis technique paved the way for freely continuous neurochemical sampling from the brains of waking animals. Acquisition of cortical EEG and deep-seated EEG signals by electrodes implantation offered the means of extracting spontaneous EEG and evoked potential from waking animals. Automatic analysis(including time-domain analysis and frequency-domain analysis) of mass data by computer technique greatly relieved us from the burdensome task of manual analysis.The balance of excitatory and inhibitory signal pathways in CNS (central nervous system) is a dynamic interacting procedure of different substances, cells, structures etc. In normal status, this procedure keeps running smoothly to maintain many functions of CNS. However, when a body is over stimulated, this balance will corrupt, which will bring abnormal changes in the body including molecules, cells, structures and even behavior. As a result, the system might lose its balance, and the body is very likely to be affected by all kinds of diseases. The mechanisms of excitation and inhibition in CNS closely correlated with the changes of neuroelectrophysiological and neurochemical signals.Most of the pharmacological methods that have been used to study excitation and inhibition phenomena mainly fall into three categories: behavior experiment methods, neurophysiological experiment methods and neurochemical experiment methods. Jujuboside A ( JuA) is a main component of Jujubogenin extracted from the seed of Ziziphus (Ziziphus jujuba Mill Var spinosa ( Bunge ) Hu ex H F Chou ) , a popular Chinese herb medicine, which has long been known as a sedative-hypnotic on the CNS. The behavioral experimental studies had revealed that, the extraction of the seed of Ziziphus could inhibit the spontaneous activity and facilitate the hypnotic action of pentobarbital, but the detailed mechanism of its action is still not fully understood.The main purpose of this paper was to set up new pharmacological study methods by using cross-disciplinary modern detection techniques, and establish a method of simultaneous in vivo cortical EEG and neurotransmitters detection in rats to monitor neuroelectrophysiological and neurochemical signals at the same time. Then with the indexes of behavior change, CNS neuroelectrophysiological and neurochemical change obtained, we can investigate the effects of drugs on CNS synthetically, analyze and reveal the action mechanisms of sedative drug JuA. The correlation between neuroelectrophysiological and neurochemical signals can also be investigated.The method of glutamate detection in hippocampal area with the HPLC system and the microdialysis/microinjection technique was set up. It was reported that penicillin could break the balance of excitatory and inhibitory signal pathways in CNS when applied to the neural tissue directly and is always used as an agitator of CNS. The change of the glutamate level in hippocampal area induced by penicillin was detected with HPLC associated with the microdialysis and in vivo sampling technique. Penicillin was injected into lateral ventricle through microinjection probe and the microdialysis was performed to detect the level of hippocampal glutamate. The glutamate concentration increased greatly with the application of penicillin 1000KIU/L and higher dose brought the behavioral seizure symptoms. When JuA was co-injected into the lateral ventricle with penicillin, the increase of glutamate induced by penicillin decreased with the dose of JuA. From this, it can be deduced that JuA reversed the effects of penicillin on the level of hippocampal glutamate.A new method of simultaneous in vivo cortical EEG and hippocampal glutamate(Glu) detection in rats was established in order to monitor neuroelectrophysiological and neurochemical signals at the same time. EEG signals were recor...