Kazuhiko Fukuda

Nitric Oxide Induces Hypoxia-inducible Factor 1 Activation That Is Dependent on MAPK and Phosphatidylinositol 3-Kinase Signaling

Hypoxia-inducible factor-1 (HIF-1) is a master regulator of cellular adaptive responses to hypoxia. Levels of the HIF-1α subunit increase under hypoxic conditions. Exposure of cells to certain nitric oxide (NO) donors also induces HIF-1α expression under nonhypoxic conditions. We demonstrate that exposure of cells to the NO donor NOC18 or S-nitrosoglutathione induces HIF-1α expression and transcriptional activity. In contrast to hypoxia, NOC18 did not inhibit HIF-1α hydroxylation, ubiquitination, and degradation, indicating an effect on HIF-1α protein synthesis that was confirmed by pulse labeling studies. NOC18 stimulation of HIF-1α protein and HIF-1-dependent gene expression was blocked by treating cells with an inhibitor of the phosphatidylinositol 3-kinase or MAPK-signaling pathway. These inhibitors also blocked NOC18-induced phosphorylation of the translational regulatory proteins 4E-BP1, p70 S6 kinase, and eIF-4E, thus providing a mechanism for the modulation of HIF-1α protein synthesis. In addition, expression of a dominant-negative form of Ras significantly suppressed HIF-1 activation by NOC18. We conclude that the NO donor NOC18 induces HIF-1α synthesis under conditions of NO formation during normoxia and that hydroxylation of HIF-1α is not regulated by NOC18.

Delayed discharge and acceptability of ambulatory surgery in adult outpatients receiving general anesthesia

PurposeDelay in discharge after ambulatory surgery impairs its cost-effectiveness. However, it is not self-evident that prolonged postoperative stay is associated with low quality of care and patient acceptability of ambulatory surgery. The aims of this study were to document factors affecting delay in discharge, recovery profiles, and patient acceptability in adult outpatients.MethodsPerioperative data were collected prospectively on consecutive 726 adult same-day surgical patients receiving general anesthesia. Factors that affected home-readiness, discharge, and unanticipated admission were noted. Patients were followed up 24u2009h after discharge using a standardized questionnaire to identify postdischarge symptoms, patient’s self-rated resumption of normal activity (RNA) level, and preference of outpatient procedure.ResultsEighty-two percent of patients were discharged home <270u2009min after operation, 16% were delayed (≥270u2009min), and 2% required unanticipated admission. Delayed patients reported postdischarge pain more frequently (53%) and a lower 24-h postoperative RNA level (7.2 ± 1.8) and preference ratio (76%) than no-delay patients (34%, 8.0 ± 1.9, 87%, respectively; P < 0.001). Delay in home-readiness (≥165u2009min) was mainly due to an adverse symptom, and delay in discharge after reaching home-readiness (≥150u2009min) was mainly due to a persistent symptom (58%) or a social/system problem (34%). Causes of admission were perioperative complications (80%) or social reasons (20%).ConclusionDelays in discharge are mainly due to adverse symptoms or social/system problems. Delayed discharge is associated with increased postdischarge pain, lower RNA level, and patient acceptability. Appropriate care of postoperative symptoms and system management could prevent delay in discharge and improve patient RNA level and acceptability.

Activity of the serotonergic system during isoflurane anesthesia

BACKGROUND:Microdialysis studies have demonstrated that the release of serotonin (5-hydroxytryptamine, 5-HT) in the serotonergic projection areas increases during waking and decreases during sleep in rat and cat, suggesting that 5-HT plays an important role in modulation of sleep. Although it might be expected that 5-HT release is also decreased during general anesthesia, the functional contribution of serotonergic neurons in pharmacological effects of volatile anesthetics has not been fully investigated. METHODS:Using an in vivo microdialysis technique, we measured extracellular 5-HT in rat frontal cortex during waking, slow-wave sleep, and isoflurane anesthesia. To assess the involvement of the serotonergic system in the hypnotic action of isoflurane, the concentration of isoflurane required for loss of righting reflex was determined with or without pretreatment of fluoxetine hydrochloride, a selective 5-HT reuptake inhibitor. RESULTS:During slow-wave sleep and isoflurane anesthesia (0.1–1.5 MAC), 5-HT release decreased to 21%–44% of that during the waking state. Loss of righting reflex occurred at significantly higher isoflurane concentrations in fluoxetine-treated rats (0.76% ± 0.03% [n = 8]) than in control rats (0.60% ± 0.01% [n = 8]). CONCLUSIONS:It is suggested that a change in the activity of the serotonergic system in the brain is involved in the hypnotic action of isoflurane.

The intravenous anesthetic propofol inhibits hypoxia-inducible factor 1 activity in an oxygen tension-dependent manner.

Hypoxia elicits a wide range of responses that occur at different organizational levels in the body. Hypoxia is not only a signal for energy conservation and metabolic change, but triggers expression of a select set of genes. The transcription factor hypoxia‐inducible factor 1 (HIF‐1) is now appreciated to be a master factor of the gene induction. Although knowledge on molecular mechanisms of HIF‐1 activation in response to hypoxia is accumulating, the molecular mechanism of maintenance of HIF‐1 activity under normoxic conditions remains to be elucidated. We demonstrate that the intravenous anesthetic propofol reversibly inhibits HIF‐1 activity and the gene expression mediated by HIF‐1 by blocking the synthesis of the HIF‐1α subunit under 20% or 5% O2 conditions, but not under 1% O2 conditions.

The effect of sevoflurane on ciliary motility in rat cultured tracheal epithelial cells: a comparison with isoflurane and halothane.

Halothane and isoflurane potently depress airway ciliary motility. We compared the effect of sevoflurane on ciliary beat frequency (CBF) with that of halothane and isoflurane using purified and cultured rat tracheal epithelial cells. Rat tracheal epithelial cells were isolated from adult male Sprague-Dawley rats to establish an air-liquid interface culture. Apical surfaces of the cells were exposed to a fresh gas containing humidified and warmed (25°C) air (vehicle) with or without sevoflurane (0%–4%), halothane (0%–2%), or isoflurane (0%–2%). The images of motile cilia were videotaped and CBF was analyzed using a computer. Baseline CBF (= 100%) and CBF 30 min after the exposure were measured. CBF 30 min after vehicle exposure was 101% ± 4% (mean ± sd). Exposures to 0.25%–2% sevoflurane did not change CBF significantly, although exposures to 0.25%–2% halothane or isoflurane decreased CBF dose-dependently. CBFs 30 min after exposures to 2% of sevoflurane, halothane, and isoflurane were 97% ± 9%, 56% ± 14%, and 47% ± 6%, respectively (n = 5 each). Sevoflurane 4% reduced CBF significantly but slightly (84% ± 2%, n = 5). These results show that sevoflurane has a direct cilioinhibitory action but its action is much weaker than that of halothane and isoflurane in isolated rat tracheal epithelial cells.

Omission of fentanyl during sevoflurane anesthesia decreases the incidences of postoperative nausea and vomiting and accelerates postanesthesia recovery in major breast cancer surgery

PurposeOur purpose was to investigate the effect of omission of fentanyl during sevoflurane anesthesia on the incidences of postoperative nausea and vomiting and on postanesthesia recovery in female patients undergoing major breast cancer surgery.MethodsFemale patients (American Society of Anesthesiologists [ASA] physical status [PS] class I-II; age, 28–84 years) undergoing major breast cancer surgery were randomized to one of two anesthesia maintenance groups: sevoflurane-fentanyl anesthesia (SF; n = 25) or fentanyl-free sevoflurane anesthesia (S; n = 26). All patients were administered with propofol 2u2009mg·kg−1 intravenously for anesthesia induction, a laryngeal mask airway was placed, and they received rectal diclofenac and local infiltration anesthesia. Anesthesia was maintained with sevoflurane in oxygen-air and they breathed spontaneously. The patients in group SF received fentanyl 0.1u2009mg intravenously and those in group S received normal saline during anesthesia.ResultsGroup SF revealed higher incidences of postoperative nausea (68% vs 27%) and vomiting (32% vs 8%) in the first 24 postoperative hours than group S. The median (25th–75th percentile) length of time from postanesthesia care unit (PACU) admission to ambulation was significantly longer in group SF (n = 23) at 195u2009min (158–219u2009min), than in group S, at 141u2009min (101–175u2009min). Two patients in group SF could not walk during the PACU stay.ConclusionOmission of fentanyl during sevoflurane anesthesia, combined with diclofenac and local infiltration anesthesia, decreases the incidences of postoperative nausea and vomiting and accelerates postanesthesia recovery in patients undergoing major breast cancer surgery.

Differential effects of intravenous anesthetics on ciliary motility in cultured rat tracheal epithelial cells

Objectif nLa fonction ciliaire des voies aeriennes est affectee par certains anesthesiques ou sedatifs qui peuvent predisposer des patients anesthesies, ou en soins intensifs, a ľhypoxemie, ľatelectasie et ľinfection pulmonaire. Les effets des midazolam, propofol, dexmedetomidine, ketamine, fentanyl, thiopental et pentobarbital sur la frequence des battements ciliaires (FBC) de cellules epitheliales tracheales de rat (ETR), isolees et cultivees, ont ete etudies pour verifier leur action directe sur la FBC tout en ecartant ľinfluence des cellules non epitheliales.PurposeIt has been shown that airway ciliary function is impaired by several anesthetic or sedative drugs, which may predispose anesthetized or intensive care patients to respiratory complications, such as hypoxemia, atelectasis and pulmonary infection. We studied the effects of midazolam, propofol, dexmedetomidine, ketamine, fentanyl, thiopental and pentobarbital on ciliary beat frequency (CBF) in isolated and cultured rat tracheal epithelial (RTE) cells, to investigate their direct CBF action removing influences of non-epithelial cells.MethodsRat tracheal epithelial cells were purely isolated from tracheas of adult male Sprague-Dawley rats. After 14 to 21 days of culture, the images of motile cilia were videotaped using a phase-contrast microscope. Baseline CBF and CBF 30 or 50 min after administration of vehicle or one of the above agents were computer-analyzed.ResultsMidazolam (0.3–10 μM), propofol (1-100 μM), dexmedetomidine (1–100 nM), fentanyl (0.1–10 nM) and thiopental (30–300 μM) had no effect on CBF. Ketamine at a supraclinical dose (1000 μM) increased CBF (22 ± 13, mean ± standard deviation, % increase from baseline; baseline = 100%) significantly (P < 0.01). Fentanyl at a high clinical dose (100 nM) increased CBF significantly (10 ± 9%). Pentobarbital decreased CBF dose-dependently (100 μM, -2 ± 6%; 300 μM,-14 ± 18%; 1000 μM, -75 ± 5%) and reversibly (P < 0.01).ConclusionThese results show that midazolam, propofol, dexmedetomidine and thiopental have no direct action on CBF in isolated RTE cells, whereas high doses of ketamine and fentanyl have direct ciliostimulatory actions and pentobarbital has a direct cilioinhibitory action.RésuméObjectifLa fonction ciliaire des voies aériennes est affectée par certains anesthésiques ou sédatifs qui peuvent prédisposer des patients anesthésiés, ou en soins intensifs, à ľhypoxémie, ľatélectasie et ľinfection pulmonaire. Les effets des midazolam, propofol, dexmédétomidine, kétamine, fentanyl, thiopental et pentobarbital sur la fréquence des battements ciliaires (FBC) de cellules épithéliales trachéales de rat (ETR), isolées et cultivées, ont été étudiés pour vérifier leur action directe sur la FBC tout en écartant ľinfluence des cellules non épithéliales.MéthodeDes cellules épithéliales de trachée de rats, mâles adultes Sprague-Dawley, ont été isolées. Après 14 à 21 jours de culture, les images vidéo de cils mobiles ont été enregistrées en utilisant un microscope à contraste de phase. La FBC de base, et celle de 30 ou 50 min après ľadministration du véhicule, ou ďun des médicaments, ont été analysées par ordinateur.RésultatsLes midazolam (0,3–10 μM), propofol (1–100 μM), dexmédétomidine (1–100 nM), fentanyl (0,1–10 nM) et thiopental (30–300 μM) n’ont pas eu ďeffet sur la FBC. La kétamine, à dose supraclinique (1000 μM), a augmenté la FBC (22 ± 13, moyenne ± écart type, % ďaugmentation; données de base = 100 %) de manière significative (P < 0,01). Le fentanyl, à forte dose (100 nM), a significativement augmenté la FBC (10 ± 9 %). Le pentobarbital a diminué la FBC en fonction de la dose (100 μM, -2 ± 6 %; 300 μM, -14 ± 18 %; 1000 μM, -75 ± 5 %) et de façon réversible (P < 0,01).ConclusionLes midazolam, propofol, dexmédétomidine et thiopental n’ont pas ďaction directe sur la FBC de cellules ETR isolées, tandis que de fortes doses de kétamine et de fentanyl ont une action ciliostimulante directe et que le pentobarbital a une action clio-inhibitrice directe.

The involvement of the nociceptin receptor in the antinociceptive action of nitrous oxide

Nociceptin and its receptor are widely expressed in the central nervous system and are involved in the modulation of nociception. We have previously reported that the minimum anesthetic alveolar concentrations for volatile anesthetics do not differ between nociceptin receptor knockout (NOP−/−) mice and wild-type (NOP+/+) mice. In the present study, we investigated whether the nociceptin system is involved in the antinociceptive action of nitrous oxide. Using the acetic acid-induced writhing test, we showed that nitrous oxide had significantly less analgesic action in NOP−/− mice than in NOP+/+ mice. Furthermore, when anesthetized with a mixture of halothane and nitrous oxide (70%), intraperitoneal injection of acetic acid resulted in an increase of plasma adrenocorticotropic hormone concentrations in NOP−/− mice but not in NOP+/+ mice. An immunohistochemical study showed that nitrous oxide exposure induced c-Fos expression in the spinal cords of NOP+/+ mice but not in those of NOP−/− mice. These results together suggest that the antinociceptive action of nitrous oxide is, at least partly, mediated by the nociceptin system.

The role of CRF1 receptors for sympathetic nervous response to laparotomy in anesthetized rats

Corticotropin-releasing factor (CRF) is released in response to various types of stressors and mediates endocrine, autonomic, immune, and behavioral responses to stress through interaction with CRF1 and CRF2 receptors. To investigate the role of CRF1 receptors in physiological responses to surgical stress, we analyzed the effects of two different non-peptide selective CRF1 receptor antagonists (JTC-017 and CP-154,526) and a peptide non-selective CRF receptor antagonist (astressin) on laparotomy-induced sympathetic nervous responses in isoflurane-anesthetized rats. JTC-017, CP-154,526, and astressin similarly suppressed plasma ACTH elevation induced by laparotomy. JTC-017 and CP-154,526 significantly augmented plasma noradrenaline and adrenaline responses to laparotomy, while astressin showed no effect on these responses. Laparotomy-induced maximum increases in mean blood pressure and heart rate were augmented by JTC-017, but were not affected by astressin. The results suggested for the first time that there was a pathway to attenuate sympathetic nervous response to surgical stress through CRF1 receptors in the central nervous system.

The effects of local anesthetics on cellular hypoxia-induced gene responses mediated by hypoxia-inducible factor 1

PurposeHypoxia (reduced oxygen availability) induces a series of adaptive physiological responses. At the cellular level, the adaptation includes a switch of energy metabolism from oxidative phosphorylation to anaerobic glycolysis, increased glucose uptake, and the expression of stress proteins related to cell survival. One of the most important transcription factors that activate the expression of oxygen-regulated genes is hypoxia-inducible factor 1 (HIF-1). We previously reported that halothane inhibits the hypoxia-induced HIF-1 activation. In this study, we investigated the effect of local anesthetics on HIF-1 activation and its downstream gene expression.MethodsThe established cell line Hep3B and SK-N-MC cells were exposed to 1% O2 with or without treatment by either lidocaine or bupivacaine. Expression of subunits of HIF-1, HIF-1α, and HIF-1β was examined by Western blot using specific antibodies. Expression of mRNA of HIF-1 and the HIF-1-dependent genes was investigated by RT-PCR and reporter assay.ResultsNeither of the local anesthetics tested affected the accumulation of HIF-1α induced by hypoxia, nor did they affect NOC18-induced HIF-1α accumulation. Moreover, they had no effects on HIF-1-mediated hypoxia-induced gene expression.ConclusionThe local anesthetics lidocaine and bupivacaine did not affect the HIF-1-dependent cellular hypoxia-induced gene responses.