Fine-tuning pH sensor H98 by remote essential residues in the hydrogen-bond network of mTASK-3.

TASK-3 generates a background K+ conductance which when inhibited by acidification depolarizes membrane potential and increases cell excitability. These channels sense pH by protonation of histidine residue H98, but recent evidence revealed that several other amino acid residues also contribute to TASK-3 pH sensitivity, suggesting that the pH sensitivity is determined by an intermolecular network. Here we use electrophysiology and molecular modeling to characterize the nature and requisite role(s) of multiple amino acids in pH sensing by TASK-3. Our results suggest that the pH sensor H98 and consequently pH sensitivity is influenced by remote amino acids that function as a hydrogen-bonding network to modulate ionic conductivity. Among the residues in the network, E30 and K79 are the most important for passing external signals near residue S31 to H98. The hydrogen-bond network plays a key role in selectivity or pH sensing in mTASK-3, and E30 and S31 in the network can modulate the conductive properties (E30) or reverse the pH sensitivity and selectivity of the channel (S31). Molecular dynamics simulations and pK1/2 calculation revealed that double mutants involving H98 + S31 primarily regulate the structure stability of the pore selectivity filter and pore loop regions, further strengthen the stability of the cradle suspension system, and alter the ionization state of E30 and K79, thereby preventing pore conformational change that normally occurs in response to varying extracellular pH. These results demonstrate that crucial residues in the hydrogen-bond network can remotely tune the pH sensing of mTASK-3 and may be a potential allosteric regulatory site for therapeutic molecule development.

Painful diabetic neuropathy: The role of ion channels.

Painful diabetic neuropathy (PDN) is a common chronic complication of diabetes that causes neuropathic pain and negatively affects the quality of life. The management of PDN is far from satisfactory. At present, interventions are primarily focused on symptomatic treatment. Ion channel disorders are a major cause of PDN, and a complete understanding of their roles and mechanisms may provide better options for the clinical treatment of PDN. Therefore, this review summarizes the important role of ion channels in PDN and the current drug development targeting these ion channels.

Deciphering the Molecular Mechanism of Escin against Neuropathic Pain: A Network Pharmacology Study.

Background: Escin is the main active component in Aesculus hippocastanum. It has been demonstrated that escin has anti-inflammatory properties. This study combined the methods of network pharmacology, molecular docking, and molecular dynamics to explore the molecular mechanism of escin against neuropathic pain (NP). Methods: The Swiss Target Prediction and the Pharm Mapper database were employed for predicting the targets of escin. Also, the candidate targets of NP were gathered via the databases including Therapeutic Targets, DisGeNet, GeneCards, DrugBank, and OMIM. Subsequently, the network of protein-protein interaction was screened for the key targets by the software Cytoscape 3.8.0. Then, the intersection of these targets was analysed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Additionally, we further investigated the ligand-target interactions by molecular docking and molecular dynamics simulations. Results: In total, 94 escin targets were predicted by network pharmacology. Among them, SRC, MMP9, PTGS2, and MAPK1 were the core candidate targets. Subsequently, the analysis of GO and KEGG enrichment revealed that escin affected NP by regulating protein kinase C, MAP kinase, TRP channels, the T-cell receptors signaling pathway, and the TNF signaling pathway. The results of molecular docking and molecular dynamics simulation confirmed that escin not only had a strong binding activity with the four core target proteins but also stably combined in 50 ns. Conclusions: Our study revealed that escin acts on the core targets SRC, MMP9, PTGS2, MAPK1, and associated enrichment pathways to alleviate neuronal inflammation and regulate the immune response, thus exerting anti-NP efficacy. This study provided innovative ideas and methods for the promising treatment of escin in relieving NP.

Advances in the Understanding of Two-Pore Domain TASK Potassium Channels and Their Potential as Therapeutic Targets.

TWIK-related acid-sensitive K+ (TASK) channels, including TASK-1, TASK-3, and TASK-5, are important members of the two-pore domain potassium (K2P) channel family. TASK-5 is not functionally expressed in the recombinant system. TASK channels are very sensitive to changes in extracellular pH and are active during all membrane potential periods. They are similar to other K2P channels in that they can create and use background-leaked potassium currents to stabilize resting membrane conductance and repolarize the action potential of excitable cells. TASK channels are expressed in both the nervous system and peripheral tissues, including excitable and non-excitable cells, and are widely engaged in pathophysiological phenomena, such as respiratory stimulation, pulmonary hypertension, arrhythmia, aldosterone secretion, cancers, anesthesia, neurological disorders, glucose homeostasis, and visual sensitivity. Therefore, they are important targets for innovative drug development. In this review, we emphasized the recent advances in our understanding of the biophysical properties, gating profiles, and biological roles of TASK channels. Given the different localization ranges and biologically relevant functions of TASK-1 and TASK-3 channels, the development of compounds that selectively target TASK-1 and TASK-3 channels is also summarized based on data reported in the literature.

Putative Roles of Astrocytes in General Anesthesia.

General anesthetics are a mainstay of modern medicine, and although much progress has been made towards identifying molecular targets of anesthetics and neural networks contributing to endpoints of general anesthesia, our understanding of how anesthetics work remains unclear. Reducing this knowledge gap is of fundamental importance to prevent unwanted and life-threatening side-effects associated with general anesthesia. General anesthetics are chemically diverse, yet they all have similar behavioral endpoints, and so for decades, research has sought to identify a single underlying mechanism to explain how anesthetics work. However, this effort has given way to the 'multiple target hypothesis' as it has become clear that anesthetics target many cellular proteins, including GABAA receptors, glutamate receptors, voltage-independent K+ channels, and voltagedependent K+, Ca2+ and Na+ channels, to name a few. Yet, despite evidence that astrocytes are capable of modulating multiple aspects of neural function and express many anesthetic target proteins, they have been largely ignored as potential targets of anesthesia. The purpose of this brief review is to highlight the effects of anesthetic on astrocyte processes and identify potential roles of astrocytes in behavioral endpoints of anesthesia (hypnosis, amnesia, analgesia, and immobilization).

Dorsal penile nerve block alleviates pain in men undergoing rigid cystoscopy: A single-center, randomized, double-blind, and placebo-controlled trial.

Objective: To assess the effectiveness and safety of dorsal penile nerve block (DPNB) compared with tetracaine gel in analgesia for men undergoing rigid cystoscopy. Patients and methods: This study was conducted as a prospective, randomized, double-blind, placebo-controlled, and single-center trial. Men undergoing diagnostic rigid cystoscopy were randomly allocated into one of three groups (n = 86 each): (1) tetracaine gel group (DPNB with saline), (2) DPNB group (DPNB with ropivacaine + plain lubricant), and (3) combination group (DPNB with ropivacaine + tetracaine gel). The primary outcome was visual analog scale (VAS) for pain at cystoscopic inspection of the external sphincter. Results: VAS (median [interquartile]) at inspection of the external sphincter was significantly lower in both DPNB and combination groups than that in tetracaine gel group (4 [3-6] and 4 [3-5] vs 6 [5-7], P < .0001), with a 33% reduction of median VAS. Overall pain level during procedure was significantly alleviated in the DPNB and combination groups with more stabilized HR and MAP when compared with tetracaine gel group. No adverse events were observed during DPNB including penile hematoma, erection, local anesthetic toxicosis or incompletion of cystoscopy. Conclusion: Our study suggests analgesia provided by DPNB with or without tetracaine gel instilled is superior to that provided by tetracaine gel alone in men undergoing diagnostic rigid cystoscopy. Clinical Trials Registration: ClinicalTrials.gov registration number: NCT02502487.

Isoflurane inhibits a Kir4.1/5.1-like conductance in neonatal rat brainstem astrocytes and recombinant Kir4.1/5.1 channels in a heterologous expression system.

All inhalation anesthetics used clinically including isoflurane can suppress breathing; since this unwanted side effect can persist during the postoperative period and complicate patient recovery, there is a need to better understand how isoflurane affects cellular and molecular elements of respiratory control. Considering that astrocytes in a brainstem region known as the retrotrapezoid nucleus (RTN) contribute to the regulation of breathing in response to changes in CO2/H+ (i.e., function as respiratory chemoreceptors), and astrocytes in other brain regions are highly sensitive to isoflurane, we wanted to determine whether and how RTN astrocytes respond to isoflurane. We found that RTN astrocytes in slices from neonatal rat pups (7-12 days postnatal) respond to clinically relevant levels of isoflurane by inhibition of a CO2/H+-sensitive Kir4.1/5.1-like conductance [50% effective concentration (EC50) = 0.8 mM or ~1.7%]. We went on to confirm that similar levels of isoflurane (EC50 = 0.53 mM or 1.1%) inhibit recombinant Kir4.1/5.1 channels but not homomeric Kir4.1 channels expressed in HEK293 cells. We also found that exposure to CO2/H+ occluded subsequent effects of isoflurane on both native and recombinant Kir4.1/5.1 currents. These results identify Kir4.1/5.1 channels in astrocytes as novel targets of isoflurane. These results suggest astrocyte Kir4.1/5.1 channels contribute to certain aspects of general anesthesia including altered respiratory control.NEW & NOTEWORTHY An unwanted side effect of isoflurane anesthesia is suppression of breathing. Despite this clinical significance, effects of isoflurane on cellular and molecular elements of respiratory control are not well understood. Here, we show that isoflurane inhibits heteromeric Kir4.1/5.1 channels in a mammalian expression system and a Kir4.1/5.1-like conductance in astrocytes in a brainstem respiratory center. These results identify astrocyte Kir4.1/5.1 channels as novel targets of isoflurane and potential substrates for altered respiratory control during isoflurane anesthesia.

Injection of D1 receptor antagonist SCH23390 into the periaqueductal gray attenuates morphine withdrawal symptoms in rats.

The aim of this study was to investigate the relationship of dopamine D1 receptor (D1R) and its downstream factors with morphine withdrawal symptoms in rats. Rats were injected intraperitoneally with morphine in a dose-escalating manner. The midbrain periaqueductal gray (PAG) area was microinjected with D1R antagonist SCH23390 or D1R agonist SKF38393. Rats were intraperitoneally injected with naloxone (4 mg/kg) after the last morphine injection, and the withdrawal response was observed. The D1R antagonist reduced the withdrawal response in morphine-exposed rats and decreased the expression of Ca2+/calmodulin-dependent protein kinase II (CaMKII), phosphorylated extracellular signal-regulated kinase (p-ERK) and cAMP response element-binding protein (CREB) in the PAG. However, the ability of SKF38393 to increase the withdrawal response was weak and limited. Taken together, the results suggest that D1R antagonist decreased the withdrawal response in morphine-exposed rats by downregulating the downstream factors, CaMKII, p-ERK and CREB.

Sevoflurane- and propofol-based regimens show comparable effect on oxygenation in patients undergoing cardiac valve replacement with cardiopulmonary bypass.

BACKGROUND: Our study aimed to compare the effects of Sevoflurane- and propofol-based anaesthetic regimens on oxygenation during the early period of cardiopulmonary bypass (CPB) in patients undergoing cardiac valve-replacement surgery. METHODS: Patients undergoing mechanical mitral, aortic or double valve replacement were enrolled and randomly divided into two groups: the sevoflurane-based anaesthetic regimen group consisted of patients who received 1-3% sevoflurane inhalation during anaesthesia maintenance and the propofol-based anaesthetic regimen group consisted of patients who received 6-10 mg/kg/h of propofol infusion during anaesthesia maintenance. The partial pressure of oxygen/fraction of inspired oxygen (PaO2/FiO2), respiratory mechanics and haemodynamics were recorded during CPB. RESULTS: Forty-two patients met the eligibility criteria for the study. The groups did not differ in terms of clinical and demographic characteristics, and pre- and intra-operative features. Changes in oxygenation were mild (mean PaO2/FiO2 from 358 ± 82 to 471 ± 106 mmHg) within one hour of CPB in our patients. There were no differences in PaO2/FiO2, respiratory mechanics and haemodynamics between the sevoflurane and propofol groups. CONCLUSIONS: In patients undergoing cardiac valve replacement with CPB, lung injury was mild, and sevoflurane- and propofol-based anaesthetic regimens showed similar effect on oxygenation, respiratory mechanics and haemodynamics during the early stage of CPB.

Amelioration of postoperative cognitive dysfunction in mice by mesenchymal stem cell-conditioned medium treatments is associated with reduced inflammation, oxidative stress and increased BDNF expression in brain tissues.

OBJECTIVE: Mesenchymal stem cells (MSCs) are widely used in regeneration and repair of various tissues and organs, and whether MSC-conditioned medium (MSC-CM) has protective effects in postoperative cognitive dysfunction (POCD) remains largely unknown. We aimed to assess the therapeutic effect and explore the mechanisms of MSC-CM therapy in a POCD mouse model. METHODS: Sixty C57BL/6 mice were randomly assigned to 3 groups: control, POCD and POCD + MSC-CM. The POCD mouse model was established by left liver lobectomy. While mice in the control group were sham-operated, mice in the POCD + MSC-CM group were immediately administrated with MSC-CM after operation. The Morris water maze was used to determine cognitive function of mice at 1, 3, and 7 days after operation. The levels of IL-1ß, IL-6, TNF-α and malondialdehyde in brain tissues at 3 days after operation were assessed by ELISA, while the protein level of brain derived neurotrophic factor (BDNF) was determined by western blot. RESULTS: Left liver lobectomy induced POCD in mice resulted in decrease of cognitive function, increase of brain IL-1ß, IL-6, TNF-α and malondialdehyde levels, and decreased BDNF expression, while administration of MSC-CM significantly reversed these changes. CONCLUSION: MSC-CM ameliorates POCD in mice, and its protective roles are associated with reduced levels of inflammatory factors, attenuated oxidative stress, and increased BDNF expression.

Sevoflurane Posttreatment Attenuates Lung Injury Induced by Oleic Acid in Dogs.

BACKGROUND: In animal models, both sevoflurane and propofol protect against acute lung injury (ALI), especially when administered prior to ALI onset. We hypothesized that when compared to propofol, sevoflurane administration after the onset of acute respiratory distress syndrome would mitigate oleic acid (OA)-induced ALI in dogs. METHODS: Dogs were randomly assigned to receive intravenous OA to induce ALI (n = 7 for each OA group) or saline as an OA control (n = 6 for each control). Dogs were then mechanically ventilated for 6 hours during which propofol (5 mg/kg/h) or sevoflurane (1.0 minimum alveolar concentration) was administered for sedation. Study end points included PO2/FIO2 ratio, pulmonary arterial pressure, pulmonary edema, histology, and tumor nuclear factor-α. RESULTS: In OA-injured animals, oxygenation was worse at 1, 2, 3, and 4 hours after 6-hour mechanical ventilation in sevoflurane-sedated animals compared with propofol-sedated animals, with mean difference (95% confidence interval; propofol minus sevoflurane) of 75 (39-111), 87 (55-119), 66 (44-87), and 67 (27-107) mm Hg for the respective time points. However, sevoflurane reduced the elevated pulmonary arterial pressure and vascular resistance, attenuated pulmonary edema as evidenced by reduced extravascular lung water index, and decreased tumor nuclear factor-α and diffuse alveolar damage score compared with propofol in the OA-injured lungs. CONCLUSIONS: When compared with propofol, sevoflurane attenuates OA-induced lung damage. However, despite this effect on lung histology and inflammation, sevoflurane worsened oxygenation in OA-induced ALI, possibly via inhibition of hypoxic pulmonary vasoconstriction.

Ethanol alters the expression of ion channel genes in Daphnia pulex.

BACKGROUND: Heavy drinking can increase heart rate and blood glucose, induce hypoxic tolerance, impair brain cognitive functions, and alter gene expressions. These phenomena may occur even in response to small dose of ethanol exposure or during its withdrawal. OBJECTIVES: To evaluate whether persistent low concentrations of ethanol exposure affect organism function and the gene expressions of ion channels. METHODS: Daphnids were randomized to receive placebo 300 min, 2 mM ethanol 300 min, or 2 mM ethanol 240 min and then placebo 60 min. Heart rate, glucose levels, phototactic behavior, and hypoxic tolerance were recorded during experiment. At the end of the study, changes in the mRNA levels of ion channel genes were assessed in response to exposure to ethanol using quantitative polymerase chain reaction (PCR) techniques. RESULTS: Heart rate was reversibly increased by ethanol withdrawal and returned to basal levels upon re-exposure to ethanol. Fifteen of 120 ion channel transcripts were affected by persistent ethanol exposure. Neither ethanol withdrawal nor persistent exposures showed an effect on blood glucose, phototactic behavior, or hypoxic tolerance. CONCLUSIONS: Small doses of ethanol can increase heart rate and alter gene expression of multiple ion channels in Daphnia pulex. Affected ion channel genes may assist in understanding the mechanism of ethanol adaptation and tolerance.

Dorsal penile nerve block for rigid cystoscopy in men: study protocol for a randomized controlled trial.

BACKGROUND: Pain is common in men undergoing rigid cystoscopy. Even with the application of a lubricant containing 2 % lidocaine, about 76 % of men suffer from mild to severe pain when undergoing rigid cystoscopy. The most painful part of the procedure for men is when the cystoscope passes through the membranous urethra. Song et al. (Neurourol Urodyn 29:592-5, 2010) did autopsies on males and found that the dorsal nerve of the penis (DNP), the terminal branch of the pudendal nerve, innervates the membranous urethra in 53.3 % of specimens. In addition, the urethral mucosa has branches of innervated DNP. Dorsal penile nerve block (DPNB) is usually used for circumcision in children, and it has been shown to provide effective analgesia for penile surgeries. In this study, we hypothesized that DPNB could reduce the overall pain level in men during rigid cystoscopy. METHODS/DESIGN: The trial is a prospective, randomized, double-blind, placebo-controlled, single-center trial to evaluate the effectiveness and safety of DPNB in analgesia for men undergoing rigid cystoscopy. Participants will be enrolled and randomly allocated into one of three groups according to the different analgesia regimens: 1) tetracaine gel group (DPNB with saline), 2) DPNB group (DPNB with ropivacaine plus plain lubricant), 3) combination group (DPNB with ropivacaine plus tetracaine gel). The primary outcome of this study is the visual analog scale (VAS, 0-10) for pain at cystoscopic inspection of the external sphincter. VAS scores evaluated at other time points serve as secondary outcomes. Vital signs are secondary outcomes that address the discomfort and pain during the procedure. Furthermore, the incidence of adverse events as secondary outcomes will also be recorded for evaluation of the safety of DPNB in rigid cystoscopy. Clinical assessments will be evaluated prior to DPNB, at administration of the lubricant gel, at cystoscopic inspection of the penile and bulbar urethra, external sphincter, prostate, and bladder, as well as at withdrawal of the cystoscope. DISCUSSION: This research will determine the effectiveness and safety of DPNB in men undergoing rigid cystoscopy. The results of this trial may have important implications for exploring the role of DPNB in analgesia for cystoscopy in men. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT02502487 (6 Jul 2015).

Establishment of An Alloxan-induced Diabetes Model in Daphnia Pulex.

Objective To establish a Daphnia model of alloxan-induced diabetes. Methods Daphnia were exposed to three different concentrations of alloxan (3, 5, and 10 mmol/L) for 30 minutes. Blood glucose and survival rate were recorded for 72 hours after alloxan insult. Sequence analysis and phylogenetic inference for glucose transporters (GLUT) were clustered with the maximum-likelihood method. Using reverse transcription and quantitative polymerase chain reaction techniques, we investigated the transcriptional changes of GLUT at 12 hours after alloxan (5 mmol/L) exposure. Results Compared with control, 3 mmol/L, and 5 mmol/L as well as 10 mmol/L alloxan initially induced transient blood glucose decline by 15% for 2 hours and 12 hours respectively. In Daphnia with 5 and 10 mmol/L alloxan, their blood glucose was persistently raised by about 150% since after 24-hour insult. Survival rate of Daphnia exposure to alloxan with concentrations of 3, 5, and 10 mmol/L were 90%, 75%, and 25% respectively. We predicted seven GLUT genes in the Daphnia genome and successfully amplified them using real-time polymerase chain reaction. Two of seven GLUT transcripts were down-regulated in Daphnia with 5 mmol/L alloxan-induced diabetes. Conclusion Alloxan-induced diabetes model was successfully established in the Daphnia pulex, suggesting diabetes-relevant experiments can be conducted using Daphnia.

[Effects of Etomidate on mRNA Expression of Ion Channels in Daphnia Pulex].

Ion channels are involved in the mechanism of anesthetic action and side effect.The transcription and expression of ion channel genes can be modulated by general anesthetics.The adverse effect of continuous infusion of etomidate has been concerned.However,the effects of etomidate on mRNA expressions of ion channel genes remain unclear.In this study,we exposed Daphnia pulexin 250µmol/L of etomidate for 240 min and observed the change of heart rate,phototactic behavior and blood glucose during the period of exposure,as well as the mRNA expressions of 120 ion channel genes at the end of the experiment.Compared to the controls,heart rate,phototactic behavior and blood glucose were not influenced by 250µmol/L of etomidate.According to the quantitative PCR results,18 of 120Daphnia pulexion channel genes transcripts were affected by persistent 240 min exposure to 250µmol/L of etomidate:2genes were upregulated and 16 genes were down-regulated,suggesting that etomidate showed effects on many different ion channels in transcription level.Systematical exploration of transcriptional changes of ion channels could contribute to understanding of the pharmacological mechanism of etomidate.

TASK Channels on Basal Forebrain Cholinergic Neurons Modulate Electrocortical Signatures of Arousal by Histamine.

Basal forebrain cholinergic neurons are the main source of cortical acetylcholine, and their activation by histamine elicits cortical arousal. TWIK-like acid-sensitive K(+) (TASK) channels modulate neuronal excitability and are expressed on basal forebrain cholinergic neurons, but the role of TASK channels in the histamine-basal forebrain cholinergic arousal circuit is unknown. We first expressed TASK channel subunits and histamine Type 1 receptors in HEK cells. Application of histamine in vitro inhibited the acid-sensitive K(+) current, indicating a functionally coupled signaling mechanism. We then studied the role of TASK channels in modulating electrocortical activity in vivo using freely behaving wild-type (n = 12) and ChAT-Cre:TASK(f/f) mice (n = 12), the latter lacking TASK-1/3 channels on cholinergic neurons. TASK channel deletion on cholinergic neurons significantly altered endogenous electroencephalogram oscillations in multiple frequency bands. We then identified the effect of TASK channel deletion during microperfusion of histamine into the basal forebrain. In non-rapid eye movement sleep, TASK channel deletion on cholinergic neurons significantly attenuated the histamine-induced increase in 30-50 Hz activity, consistent with TASK channels contributing to histamine action on basal forebrain cholinergic neurons. In contrast, during active wakefulness, histamine significantly increased 30-50 Hz activity in ChAT-Cre:TASK(f/f) mice but not wild-type mice, showing that the histamine response depended upon the prevailing cortical arousal state. In summary, we identify TASK channel modulation in response to histamine receptor activation in vitro, as well as a role of TASK channels on cholinergic neurons in modulating endogenous oscillations in the electroencephalogram and the electrocortical response to histamine at the basal forebrain in vivo. SIGNIFICANCE STATEMENT: Attentive states and cognitive function are associated with the generation of γ EEG activity. Basal forebrain cholinergic neurons are important modulators of cortical arousal and γ activity, and in this study we investigated the mechanism by which these neurons are activated by the wake-active neurotransmitter histamine. We found that histamine inhibited a class of K(+) leak channels called TASK channels and that deletion of TASK channels selectively on cholinergic neurons modulated baseline EEG activity as well as histamine-induced changes in γ activity. By identifying a discrete brain circuit where TASK channels can influence γ activity, these results represent new knowledge that enhances our understanding of how subcortical arousal systems may contribute to the generation of attentive states.

Evaluation of the antinociceptive effects of lidocaine and bupivacaine on the tail nerves of healthy rats.

This study was designed to develop a simple and effective model of tail nerve block without general anaesthesia and surgical incision, to assist in exploring and studying new local anaesthetics. Tail nerves of adult, male Sprague-Dawley rats were blocked by injecting 1% lidocaine and 0.5% bupivacaine, respectively. To evaluate the tail nerve block model, the effects of tail nerve blocks induced by two classical local anaesthetics were assessed and compared by recording disappearance and recovery time of thermal and mechanical nociception. The results showed that thermal and mechanical nociception of the tail disappeared after application of local anaesthetics but were unchanged by normal saline. No abnormal results were found in both the 3-day observation period and the pathological study, and pain thresholds of all rats recovered fully. We have thus developed an easily operated, reliable and reversible model of tail nerve block for conscious rats that can be used to evaluate efficacy, safety and pharmacokinetics of new local anaesthetics and additives.

Coagulopathy associated with cell salvage transfusion following cerebrovascular surgery.

A 35-year-old man was scheduled for dural arteriovenous fistula resection for vascular malformation under general anesthesia and a cell saver device was employed. The patient suffered from massive bleeding for the rupture of arteriovenous malformations from the beginning of the operation and 1000 mL cell-saved blood was transfused. After autologous blood transfusion and fluid resuscitation, blood oozed significantly from the surgical wounds, and the administration of cryoprecipitate and fibrinogen has no effect. The value of the activated coagulation time (ACT) increased to 999s. Considering the residual heparin in the autologous blood, ninety mg of protamine was intravenously injected, then 5 minutes later the ACT dropped to 147s. After the therapy, the surgical procedure was performed smoothly. The activated partial thromboplastin time (APTT) and the thrombin time (TT) of the postoperative venous blood was 18.9 s and 53.6 s respectively. Two days later, the APTT and the TT decreased to 12.1 s and 32.7 s without special treatment. The patient was discharged home without complications and well follow-up.

TASK Channel Deletion Reduces Sensitivity to Local Anesthetic-induced Seizures.

BACKGROUND: Local anesthetics (LAs) are typically used for regional anesthesia but can be given systemically to mitigate postoperative pain, supplement general anesthesia, or prevent cardiac arrhythmias. However, systemic application or inadvertent intravenous injection can be associated with substantial toxicity, including seizure induction. The molecular basis for this toxic action remains unclear. METHODS: We characterized inhibition by different LAs of homomeric and heteromeric K channels containing TASK-1 (K2P3.1, KCNK3) and TASK-3 (K2P9.1, KCNK9) subunits in a mammalian expression system. In addition, we used TASK-1/TASK-3 knockout mice to test the possibility that TASK channels contribute to LA-evoked seizures. RESULTS: LAs inhibited homomeric and heteromeric TASK channels in a range relevant for seizure induction; channels containing TASK-1 subunits were most sensitive and IC50 values indicated a rank order potency of bupivacaine > ropivacaine >> lidocaine. LAs induced tonic-clonic seizures in mice with the same rank order potency, but higher LA doses were required to evoke seizures in TASK knockout mice. For bupivacaine, which produced the longest seizure times, seizure duration was significantly shorter in TASK knockout mice; bupivacaine-induced seizures were associated with an increase in electroencephalogram power at frequencies less than 5 Hz in both wild-type and TASK knockout mice. CONCLUSIONS: These data suggest that increased neuronal excitability associated with TASK channel inhibition by LAs contributes to seizure induction. Because all LAs were capable of evoking seizures in TASK channel deleted mice, albeit at higher doses, the results imply that other molecular targets must also be involved in this toxic action.

Emulsified isoflurane preconditioning protects against liver and lung injury in rat model of hemorrhagic shock.

BACKGROUND: Isoflurane has demonstrated protective effects against ischemia/reperfusion injury in some organs. In this study, using the hemorrhagic shock model, we investigated whether emulsified isoflurane preconditioning protected against liver and lung injury caused by massive surgical blood loss. METHODS: Male Sprague-Dawley (SD) rats were randomly divided into five groups: a control group, a hemorrhagic shock (HS) group, an intralipid (IL) group, an isoflurane (Iso) group, and an emulsified isoflurane (E-Iso) group. Saline, intralipid, isoflurane, or emulsified isoflurane were administered over 15 min. Forty-five min after injection, hemorrhage was initiated in the experimental group. Four h after resuscitation alanine aminotransferase (ALT), protein and white blood cell (WBC) in bronchoalveolar lavage fluid (BAL), and the liver and lung histopathology were measured. The malondialdehyde (MDA) and superoxide dismutase (SOD) in the liver and lung mitochondria were tested. The survival was also observed in hemorrhagic shocked rats. RESULTS: Emulsified isoflurane enhanced survival and decreased ALT, protein and WBC in BAL, liver and lung apoptosis, and the histologic score. It also decreased MDA and increased SOD activity in mitochondria. In the IL group, liver mitochondrial SOD activity increased, while ALT, liver apoptosis and histological score decreased. In the Iso group liver and lung mitochondrial SOD activity increased, while liver and lung apoptosis decreased. CONCLUSION: Emulsified isoflurane preconditioning has a protective effect against liver and lung injury as well as improving the survival in hemorrhagic shock. The potential mechanisms involved are the inhibition of cell death and improvement of antioxidation in mitochondria.