Facilitation of Behavioral and Cortical Emergence from Isoflurane Anesthesia by GABAergic Neurons in Basal Forebrain.

General anesthesia shares many similarities with natural sleep in behavior and electroencephalogram (EEG) patterns. The latest evidence suggests that general anesthesia and sleep-wake behavior may share overlapping neural substrates. The GABAergic neurons in the basal forebrain (BF) have recently been demonstrated to play a key role in controlling wakefulness. It was hypothesized that BF GABAergic neurons may participate in the regulation of general anesthesia. Here, using in vivo fiber photometry, we found that the activity of BF GABAergic neurons was generally inhibited during isoflurane anesthesia, having obviously decreased during the induction of anesthesia and being gradually restored during the emergence from anesthesia, in Vgat-Cre mice of both sexes. Activation of BF GABAergic neurons with chemogenetic and optogenetic approaches decreased sensitivity to isoflurane, delayed induction, and accelerated emergence from isoflurane anesthesia. Optogenetic activation of BF GABAergic neurons decreased EEG δ power and the burst suppression ratio (BSR) during 0.8% and 1.4% isoflurane anesthesia, respectively. Similar to the effects of activating BF GABAergic cell bodies, photostimulation of BF GABAergic terminals in the thalamic reticular nucleus (TRN) also strongly promoted cortical activation and behavioral emergence from isoflurane anesthesia. Collectively, these results showed that the GABAergic BF is a key neural substrate for general anesthesia regulation that facilitates behavioral and cortical emergence from general anesthesia via the GABAergic BF-TRN pathway. Our findings may provide a new target for attenuating the depth of anesthesia and accelerating emergence from general anesthesia.SIGNIFICANCE STATEMENT The basal forebrain (BF) is a key brain region controlling sleep-wake behavior. Activation of GABAergic neurons in the BF potently promotes behavioral arousal and cortical activity. Recently, many sleep-wake-related brain structures have been reported to participate in the regulation of general anesthesia. However, it is still unclear what role BF GABAergic neurons play in general anesthesia. In this study, we aim to reveal the role of BF GABAergic neurons in behavioral and cortical emergence from isoflurane anesthesia and elucidate the underlying neural pathways. Understanding the specific role of BF GABAergic neurons in isoflurane anesthesia would improve our understanding of the mechanisms of general anesthesia and may provide a new strategy for accelerating emergence from general anesthesia.

Ketamine exerts dual effects on the apoptosis of primary cultured hippocampal neurons from fetal rats in vitro.

Ketamine, a noncompetitive N-methyl D-aspartate (NMDA) receptor antagonist, is widely used in pediatric clinical practice. The neuroprotective and neurotoxic effects of ketamine on brain neurons during development remain controversial. The reason may be related to the different concentrations of ketamine used in practice and the small range of concentrations used in previous studies. In this study, cultured hippocampal neurons were treated with ketamine in a wide range of concentrations to comprehensively observe the effects of different concentrations of ketamine on neurons. We demonstrated that low concentrations of ketamine (10 µM, 100 µM and 1000 µM) promoted neuronal survival (p < 0.05) and reduced neuronal apoptosis (p < 0.05) compared with those of the control group. High concentrations of ketamine (2000 µM, 2500 µM and 3000 µM) reduced neuronal survival (p < 0.05) and promoted neuronal apoptosis (p < 0.05). The p38 MAPK inhibitor SB203580 reduced neuronal apoptosis induced by high concentrations of ketamine (2500 µM) (p < 0.05). Our findings indicate that ketamine exerts a dual effect on the apoptosis of primary cultured fetal rat hippocampal neurons in vitro and that the neurotoxic effects of ketamine are related to activation of the p38 MAPK signaling pathway.

Emergency tracheal intubation peri-operative risk factors and prognostic impact after esophagectomy.

BACKGROUND: Emergent endotracheal intubation (ETI) is a serious complication after Oesophagectomy. It is still unclear that perioperative risk factors and prognosis of these patients with ETI. METHODS: Between January 2015 and December 2018, 21 patients who received ETI after esophagectomy were enrolled (ETI group) at the department of thoracic surgery, Fujian Union hospital, China. Each study subject matched one patient who underwent the same surgery in the current era were included (control group). Patient characteristics and perioperative factors were collected. RESULTS: Patients with ETI were older than those without ETI (p = 0.022). The patients with history of smoking in ETI group were significantly more than those in control group (p = 0.013). The stay-time of postanesthesia care unit (PACU) in ETI group was significantly longer than that in control group (p = 0.001). The incidence of anastomotic leak or electrolyte disorder in ETI group was also higher than that in control group (p = 0.014; p = 0.002). Logistic regression analysis indicated history of smoke (HR 6.43, 95%CI 1.39-29.76, p = 0.017) and longer stay time of PACU (HR 1.04, 95%CI 1.01-1.83, p = 0.020) both were independently associated with higher risks of ETI. The 3-year overall survival (OS) rates were 47.6% in patients with ETI and 85.7% in patients without ETI (HR 4.72, 95%CI 1.31-17.00, p = 0.018). COX regression analysis indicated ETI was an independent risk factor affecting the OS. CONCLUSION: The study indicated that history of smoking and longer stay-time in PACU both were independently associated with higher risks of ETI; and ETI was an independent risk factor affecting the OS of patients after esophagectomy. TRIAL REGISTRATION: This trial was retrospectively registered with the registration number of ChiCTR2000038549.

Emergency tracheal intubation during off-hours is not associated with increased mortality in hospitalized patients: a retrospective cohort study.

BACKGROUND: The prognosis of hospitalized patients after emergent endotracheal intubation (ETI) remains poor. Our aim was to evaluate the 30-d hospitalization mortality of subjects undergoing ETI during daytime or off-hours and to analyze the possible risk factors affecting mortality. METHODS: A single-center retrospective study was performed at a university teaching facility from January 2015 to December 2018. All adult inpatients who received ETI in the general ward were included. Information on patient demographics, vital signs, ICU (Intensive care unit) admission, intubation time (daytime or off-hours), the department in which ETI was performed (surgical ward or medical ward), intubation reasons, and 30-d hospitalization mortality after ETI were obtained from a database. RESULTS: Over a four-year period, 558 subjects were analyzed. There were more male than female in both groups (115 [70.1%] vs 275 [69.8%]; P = 0.939). A total of 394 (70.6%) patients received ETI during off-hours. The patients who received ETI during the daytime were older than those who received ETI during off-hours (64.95 ± 17.54 vs 61.55 ± 17.49; P = 0.037). The BMI of patients who received ETI during the daytime was also higher than that of patients who received ETI during off-hours (23.08 ± 3.38 vs 21.97 ± 3.25; P < 0.001). The 30-d mortality after ETI was 66.8% (373), which included 68.0% (268) during off-hours and 64.0% (105) during the daytime (P = 0.361). Multivariate Cox regression analysis found that the significant factors for the risk of death within 30 days included ICU admission (HR 0.312, 0.176-0.554) and the department in which ETI was performed (HR 0.401, 0.247-0.653). CONCLUSIONS: The 30-d hospitalization mortality after ETI was 66.8%, and off-hours presentation was not significantly associated with mortality. ICU admission and ETI performed in the surgical ward were significant factors for decreasing the risk of death within 30 days. TRIAL REGISTRATION: This trial was retrospectively registered with the registration number of ChiCTR2000038549 .

Taselisib moderates neuropathic pain through PI3K/AKT signaling pathway in a rat model of chronic constriction injury.

BACKGROUND: Neuropathic pain is a chronic condition commonly caused by inflammation-induced disturbances or lesions of somatosensory functions in the nervous system. The aim of this study was to investigate the effects and mechanisms of Taselisib on chronic constriction injury (CCI)-induced neuropathic pain in rats. METHODS: The rats were divided into four groups: sham group, sham + Taselisib (10 mg/kg orally once a day) group, CCI group, and CCI + Taselisib (10 mg/kg orally once a day) group. Pain behavioral tests, recorded by measuring paw withdrawal threshold (PWT) and thermal withdrawal latency (TWL), were conducted on days 0, 3, 7, 14, and 21 after surgery. After testing, the animals were euthanized and spinal dorsal horns were collected. Pro-inflammatory cytokines were quantified using ELISA and qRT-PCR. PI3K/pAKT signaling was assessed using Western blot and immunofluorescence. RESULTS: PWT and TWL were significantly reduced after CCI surgery, but were successfully increased by Taselisib treatment. Taselisib treatment notably suppressed the upregulation of pro-inflammatory cytokines, including IL-6, IL-1ß, and TNF-⍺. Taselisib treatment significantly reduced the elevated phosphorylation of AKT and PI3K induced by CCI. CONCLUSION: Taselisib can alleviate neuropathic pain by inhibiting the pro-inflammatory response, potentially through the PI3K/AKT signaling pathway.

Ultrasonic visualization technique for anatomical and functional analyses of the sciatic nerve in rats.

Background and objective: Ultrasound has been widely used in the diagnosis and minimally invasive treatment of peripheral nerve diseases in the clinic, but there is still a lack of feasibility analysis in rodent models of neurological disease. The purpose of this study was to investigate the changes in the cross-sectional area of the sciatic nerve of different genders and body weights and to explore the effectiveness and reliability of an ultrasound-guided block around the sciatic nerve in living rats. Methods: Using ultrasound imaging anatomy of the sciatic nerve of rats, the cross-sectional area of the sciatic nerve in rats of different genders from 6 to 10 weeks old was calculated, and then analyzed its correlation with body weight. Further analyses were conducted through behavioral and cadaveric studies to evaluate the feasibility of ultrasound-guided perineural injection of the sciatic nerve in rats. Results: We first reported that the sciatic nerve cross-sectional area of rats was increased with age (F = 89.169, P < 0.001), males had a higher sciatic nerve cross-sectional area than females (F = 60.770, P < 0.001), and there was a positive correlation with body weight (rMale = 0.8976, P < 0.001; rFemale = 0.7733, P < 0.001). Behavioral observation of rats showed that the lower extremity complete block rate was 80% following the administration of drugs around the sciatic nerve under ultrasound guidance and staining with methylene blue occurred in all sciatic nerves and surrounding muscles and fascia using 20 ultrasound-guided injections. Conclusions: Ultrasound visualization technology can be used as a new auxiliary evaluation and intervention therapy for animal models of peripheral nerve injury, and will provide overwhelming new references for the basic research of neurological diseases.

Parabrachial nucleus astrocytes regulate wakefulness and isoflurane anesthesia in mice.

Background: The parabrachial nucleus (PBN) is an important structure regulating the sleep-wake behavior and general anesthesia. Astrocytes in the central nervous system modulate neuronal activity and consequential behavior. However, the specific role of the parabrachial nucleus astrocytes in regulating the sleep-wake behavior and general anesthesia remains unclear. Methods: We used chemogenetic approach to activate or inhibit the activity of PBN astrocytes by injecting AAV-GFAabc1d-hM3Dq-eGFP or AAV-GFAabc1d-hM4Di-eGFP into the PBN. We investigated the effects of intraperitoneal injection of CNO or vehicle on the amount of wakefulness, NREM sleep and REM sleep in sleep-wake behavior, and on the time of loss of righting reflex, time of recovery of righting reflex, sensitivity to isoflurane, electroencephalogram (EEG) power spectrum and burst suppression ratio (BSR) in isoflurane anesthesia. Results: The activation of PBN astrocytes increased wakefulness amount for 4 h, while the inhibition of PBN astrocytes decreased total amount of wakefulness during the 3-hour post-injection period. Chemogenetic activation of PBN astrocytes decreased isoflurane sensitivity and shortened the emergence time from isoflurane-induced general anesthesia. Cortical EEG recordings revealed that PBN astrocyte activation decreased the EEG delta power and BSR during isoflurane anesthesia. Chemogenetic Inhibition of PBN astrocytes increased the EEG delta power and BSR during isoflurane anesthesia. Conclusion: PBN astrocytes are a key neural substrate regulating wakefulness and emergence from isoflurane anesthesia.

[Effect of ketamine combined with penehyclidine hydrochloride on the expression of synaptophysin in the brain of neonatal rats].

OBJECTIVE: To study the effects of ketamine combined with penehyclidine hydrochloride on the learning and memory abilities and the expression of synaptophysin in the hippocampus CA3 region in the brain of neonatal rats. METHODS: Eighty seven-day-old Sprague-Dawly rats were randomly intraperitoneally injected with 50 mg/kg of ketamine (K group), 2 mg/kg of penehyclidine hydrochloride (P group), 50 mg/kg of ketamine plus 2 mg/kg penehyclidine hydrochloride (PK group) or normal saline (control group). The rats were trained and tested in a Morris water maze 14 days after administration. The immunhistochemical method was used to ascertain the expression of synaptophysin in the hippocampus CA3 region 24 hrs, 14 days and 28 days after administration. RESULTS: In the Morris water maze training, the rats in the PK group performed worst, followed by the K group. The rats from the P and NS groups performed well. Compared with the NS group, the expression of synaptophysin in the K and the PK groups decreased significantly 24 hrs and 14 days after administration (p<0.05). The PK group had lower synaptophysin expression than the K group 24 hrs and 14 days after administration (p<0.05). Up to 28 days after administration, the synaptophysin expression increased in all of the four groups and there were no significant differences between groups. CONCLUSIONS: Ketamine combined with penehyclidine hydrochloride may inhibit more significantly learning and memory abilities and the synaptophysin expression in the hippocampus CA3 region than ketamine alone in neonatal rats. Penehyclidine hydrochloride alone has no effect on learning and memory abilities and the synaptophysin expression. The synaptophysin expression may increase to a normal level by training and with increasing age.

Involvement of AQP 1 in the cardio-protective effect of remifentanil post-conditioning in ischemia/reperfusion rats.

BACKGROUND: our research aim to study the role of AQP1 in the cardioprotective effect of remifentanil post-conditioning for myocardial ischemia/reperfusion injury. METHODS: Ninety Sprague-Dawley (SD) rats were divided into 6 groups: sham operation group (Sham group), myocardial ischemia and reperfusion group (I/R group), postconditioning of remifentanil group (R-post), postconditioning of remifentanil plus AQP1 inhibitor acetazolamide group (R-post +Ace), postconditioning of remifentanil plus opioid-receptor antagonist compounds (R-post +AC), postconditioning of remifentanil plus AQP1 enhancer arginine vasopressin (R-post +AV). All groups except the sham operation group were given 30 min ischemia in left anterior descending (LAD) coronary arteries. All groups were then given 120 min reperfusion to the LAD. Before reperfusion, the R-post, R-post +Ace, R-post +AC, R-post +AV groups were given 10 min remifentanil post-conditioning. Hemodynamic data were measured every 30 min after initiation of ischemia. The rats' hearts were exercised for detecting infarct size and water content in the left ventricle, and AQP1 expression were also detected. RESULTS: The R-post group showed a significant reduction of the infarct size compared to the I/R group. The effect of R-post for reducing infarct size was slightly enhanced by adding acetazolamide to R-post, so significant differences could still be found when compared R-post+Ace group to the I/R group. The effect of infarct size reduction brought by R-post was blocked by the opioid-receptor antagonist compounds. This effect was also blocked by the AQP1 enhancer. Similar outcomes were found considering the water content of the left ventricle and the AQP1 expression. CONCLUSION: Cardioprotective effect of remifentanil post-conditioning may initiate through inhibiting the function of AQP1.

[Sugar transport, metabolism, accumulation and their regulation in fruits].

Photosynthates transported into fruits are mainly in the form of sucrose in most fruit tree species; but sorbitol takes the place of sucrose in woody Rosaceae plants. The transport of sugars across the plasma membrane from apoplastic space into cells is mediated by sugar transporters. The fact that gene expression of sugar transporters is upregulated just before and during sugar accumulation suggests the participation of sugar transporters in sugar accumulation of fruit. The sucrose-metabolizing enzymes participate in four futile cycles that involve sugar transport between cytosol, vacuole, amyloplast and apoplast. The increase in SS (sucrose synthase) and SPS (sucrose phosphate synthase) activities and mRNA levels during maturation parallels the increase in sugar accumulation indicates that the sucrose-metabolizing enzymes have important roles on sugar accumulation in fruits. The prerequisite for rapid accumulation of sugar in fruit is restriction of hexose catabolism and promotion of its synthesis. In woody Rosaceae plants, the fact that sucrose metabolism is also quite active in fruit suggests that sorbitol and sucrose probably play similar roles in fruit development. Sugars as signal molecules regulate the expression of genes involved in sugar transport and metabolism. Sugar transport, metabolism and accumulation are also regulated by natural environmental factors and cultural practices. The increase in sugar content of tomato fruit in acid invertase gene antisense-inhibited plants provides promising prospect of genetic engineering as a potential effective technique in regulation of sugar accumulation in fruits. Thus, the sugar content of fruit is determined by both intrinsic and extrinsic factors. The future research works will be focused on elucidating the mechanism of sugar signal and other intrinsic signals as well as extrinsic signals including nutrients, plant hormones and physical factors on sugar transport, metabolism and accumulation and the interrelationship among them.

Dexmedetomidine versus midazolam for sedation in upper gastrointestinal endoscopy.

OBJECTIVES: To investigate the efficacy and safety of sedation with dexmedetomidine in upper gastrointestinal endoscopy. METHODS: Patients with ASA physical status I-II undergoing elective upper gastrointestinal endoscopy were randomly allocated to receive dexmedetomidine or midazolam for conscious sedation. Continuous peripheral oxygen saturation (SpO2), heart rate, mean arterial pressure (MAP), Ramsay Sedation Scale (RSS) and numeric rating scale pain scores were recorded before, during and after the procedure. Patients completed a post-procedure satisfaction questionnaire. RESULTS: Patients in the midazolam group (n = 30) experienced a significant decrease in MAP during sedation compared with pre-sedation values. Patients in the dexmedetomidine group (n = 30) had significantly higher SpO2 and RSS scores during sedation than those in the midazolam group. Overall satisfaction was higher in the dexmedetomidine group than the midazolam group. There were no clinically significant complications in either group. CONCLUSION: Dexmedetomidine has a good safety profile and is an effective sedative for use in upper gastrointestinal endoscopy.

[Gene and gene engineering of carotenoid biosynthesis].

Carotenoids have a range of diverse biological functions and actions, especially playing an important role in human health with provitamin A activity, anti-cancer activity, enhancing immune ability and so on. Human body can't synthesis carotenoids by itself and must absorb them from outside. However, carotenoid contents in many plant are very low, and many kinds of carotenoid are difficult to produce by chemical ways. With the elucidation of carotenoid biosynthetic pathway and cloning genes of relative enzymes from microorganisms and higher plants, it is possible to regulate carotenoid biosynthesis via genetic engineering. This article reviews gene cloning of carotenoid biosynthetic enzymes in microorganisms and higher plants, and advances in the studies of carotenoid production in heterologous microorganisms and crop plants using gene-manipulated carotenoid biosynthesis.