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OBJECTIVE To reveal the role of the basal forebrain(BF)GABAergic neurons in the regulation of isoflurane anesthesia and to elucidate the underlying neural pathways.METHODS The activity of BF GABAer-gic neurons was monitored during isoflurane anesthesia using a genetically encoded calcium indicator in Vgat-Cre mice of both sexes.The activity of BF GABAer-gic neurons was manipulated by chemogenetic and opto-genetic approaches.Sensitivity,induction time and emer-gence time of isoflurane anesthesia were estimated by righting reflex.The electroencephalogram(EEG)power and burst-suppression were monitored by EEG recording.The effects of activation of GABAergic BF-thalamic reticu-lar nucleus(TRN)pathway on isoflurane anesthesia were investigated with optogenetics.RESULTS The activity of BF GABAergic neurons was generally inhibited during isoflurane anesthesia,obviously decreased during the induction of anesthesia and gradually restored during the emergence from anesthesia.Activation of BF GABAergic neurons with chemogenetics and optogenetics promoted behavioral emergence from isoflurane anesthesia,with decreased sensitivity to isoflurane,delayed induction and accelerated emergence from isoflurane anesthesia.Optogenetic activation of BF GABAergic neurons prom-oted cortical activity during isoflurane anesthesia,with decreased EEG delta power and burst suppression ratio during 0.8%and 1.4%isoflurane anesthesia,respectively.Similar to the effects of activating BF GABAergic cell bod-ies,photostimulation of BF GABAergic terminals in the TRN also strongly promoted cortical activation and behav-ioral emergence from isoflurane anesthesia.CONCLU-SION The GABAergic neurons in the BF is a key neural substrate for general anesthesia regulation that facilitates behavioral and cortical emergence from general anesthe-sia via the BF-TRN pathway.
RESUMO
OBJECTIVE：To study the improvement effects of ica riin（ICA）on cognitive function in schizophrenia model rats and its mechanism. METHODS ：SD rats were divided into blank control group ，model group ，ICA low-dose ，medium-dose and high-dose groups （15，30，60 mg/kg）. Except for blank control group ，other groups were given N-methyl-D-aspartate receptor antagonist MK- 801（0.2 mg/kg）intraperitoneally to induce schizophrenia rats models ，once a day ，for consecutive 14 days. After modeling，ICA groups were intragastrically administered with the corresponding drugs ，while blank control group and model group were intragastrically administered with the same volume of water ，once a day ，for consecutive 7 days. The behavioral com changes of rats were detected by Morris water maze test ，open field test ， forced swimming test and Y maze test pathological changes of hippocampus were observed by Nissl staining；the levels of cholinergic indexes [acetylcholine （Ach），choline acetyltransferase （ChAT） and acetylcholinesterase （AchE）] in cerebral tissues were detected by ELISA. The expression of BDNF ，ERK and CREB mRNA in cerebral tissue were detected by RT-PCR ；expression or phosphorylation level of BDNF ，ERK，CREB protein ，apoptosis related proteins （Bcl-2，Bax and Caspase- 3）were detected by Western blot. RESULTS ：Compared with blank control group ，escape latency ，distance at T 1-T3， cumulative immobility time and the expression of Caspase- 3 protein in cerebral tissues were significantly increased in model group （P＜0.05）；the times of crossing platform ，alternation rate ，the number of Nissl staining positive neurons in hippocampus tissues ， the levels of Ach and ChAT in cerebral tissues ，Bcl-2/Bax ratio ，mRNA and protein expression of BDNF ，mRNA expression of ERK and CREB ，the phosphorylation of ERK 1/2 and CREB were significantly decreased （P＜0.05）.Compared with model group ， escape latency ，distance at T 1-T3，cumulative immobility time ，the number of Nissl staining positive neurons ，AchE level in cerebral tissues and relative expression of Caspase- 3 protein were significantly decreased in ICA high-dose group （P＜0.05）；the times of crossing platform ，alternation rate ，levels of Ach and ChAT in cerebral tissues ，Bcl-2/Bax ratio ，mRNA and protein expression of BDNF ，mRNA expression of ERK and CREB ，the phosphorylation of ERK 1/2 and CREB were increased significantly（P＜0.05）. Above indexes in ICA low-dose and medium-dose groups were partially improved significantly than model group（P＜0.05）. CONCLUSIONS ：ICA can improve cognitive function in schizophrenia model rats.Its mechanism may be related to regulating cholinergic system ，inhibiting neuronal apoptosis ，and promoting the expression of BDNF/ERK/CREB signaling pathway.