Facilitation of behavioral and cortical emergence from isoflurane anesthesia by GABAergic neurons in basal forebrain / 中国药理学与毒理学杂志

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.

Effect of Melatonin on the Level of Dynorphin in Rat Brain / 复旦学报（医学版）

Purpose　To observe the changes of dynorphin-like immunoreactivities of neurons in some rat brain nuclei that are related to analgesia following exogenous administration of melatonin.　Methods　The experimental rats were divided into two groups, injected intraperitoneally with melatonin 110 mg/kg and with vehicle, respectively. One hour after the injection, the rat brain was processed for coronal sections. The sections were stained with immunohistochemical ABC technique. The integral optical density (IOD) of the stained section was measured by the computer-assisted image processing technique.　Results　Dynorphin-like immunoreactivities in the supraoptic nucleus and nucleus raphe dorsalis showed obvious reduction following the single injection of melatonin.IOD values in the above nuclei were decreased significantly (P<0.01) with the melatonin treatment. In the paraventricular nucleus of hypothalamus, periaqueductal gray and nucleus raphe magnus, there was no difference (P>0.05) about the IOD values between melatonin-treated group and vehicle-treated group.　Conclusions　Melatonin may result in the decrease of dynorphin content in the supraoptic nucleus and nucleus raphe dorsalis.

Effects of ondansetron on morphine physical dependence in mice / 中国药理学通报

AIM To investigate the effects of ondansetron, a selective 5 Hydroxytryptamine3 (5 HT 3) receptor antagonist, on morphine physical dependence. METHODS The morphine dependent models in mice and in isolated Guinea pig ileum were used. RESULTS Pretreatment of ondansetron for 12 days significantly reduced morphine withdrawal symptoms in mice ,such as body weight loss(Groups 2～100 ?g?kg -1 ?d -1 ) or reduced both body weight loss and jumping times (Group 100 ?g?kg -1 ?d -1 ). In addition, concomitant treatment with ondansetron(1～20 ?mol?L -1 ) dose dependently suppressed the contraction induced by naloxone in Guinea pig ileum. CONCLUSION The chronic pretreatment of ondansetron can prevent morphine physical dependence to some extent.