Upregulation of DRG protein TMEM100 facilitates dry-skin-induced pruritus by enhancing TRPA1 channel function.

The dry skin tortures numerous patients with severe itch. The transient receptor potential cation channel V member 1 (TRPV1) and A member 1 (TRPA1) are two essential receptors for peripheral neural coding of itch sensory, mediating histaminergic and nonhistaminergic itch separately. In the dorsal root ganglion, transmembrane protein 100 (TMEM100) is structurally related to both TRPV1 and TRPA1 receptors, but the exact role of TMEM100 in itch sensory coding is still unknown. Here, in this study, we find that TMEM100 + DRG neurons account for the majority of activated neurons in an acetone-ether-water (AEW)-induced dry skin itch model, and some TMEM100 + DRG neurons are colocalized with both TRPA1 and the chloroquine-related Mrgpr itch receptor family. Both the expression and function of TRPA1 channels, but not TRPV1 channels, are upregulated in the AEW model, and specific DRG Tmem100 gene knockdown alleviates AEW-induced itch and rescues the expression and functional changes of TRPA1. Our results strongly suggest that TMEM100 protein in DRG is the main facilitating factor for dry-skin-related chronic itch, and specific suppression of TMEM100 in DRG could be a novel effective treatment strategy for patients who suffer from dry skin-induced itch.

Propofol differentially induces unconsciousness and respiratory depression through distinct interactions between GABAA receptor and GABAergic neuron in corresponding nuclei.

Propofol is the most commonly used intravenous anesthetic worldwide. It can induce loss of consciousness prior to the occurrence of severe respiratory suppression, which is also a pharmacodynamic feature of all general anesthetics. However, the neural mechanisms underlying this natural phenomenon are controversial and highly related to patient safety. In the present study, we demonstrated that the pharmacodynamic effects of propofol (50 and 100 µM) on suppression of consciousness-related excitatory postsynaptic currents in the medial prefrontal cortex (mPFC) and centromedian nucleus of the thalamus (CMT) were lower than those in the kernel respiratory rhythmogenesis nucleus pre-Bötzinger complex (PrBo). Furthermore, we unexpectedly found that the GABAA receptor ß3 subunit is the key target for propofol's action and that it is mutually and exclusively expressed in GABAergic neurons. It is also more abundant in the mPFC and CMT, but mainly co-localized with GABAergic neurons in the PrBo. As a result, the differentiated expression pattern should mediate more neuron suppression through the activation of GABAergic neurons in the mPFC and CMT at low doses of propofol (50 µM). However, PrBo GABAergic neurons were only activated by propofol at a high dose (100 µM). These results highlight the detailed pharmacodynamic effects of propofol on consciousness-related and respiration-related nuclei and provide the distinct interaction mechanism between the ß3 subunit and GABAergic neurons in mediating the suppression of consciousness compared to the inhibition of respiration.

Complete Freund's adjuvant-induced decrement of pruriceptor-mediated suppression of itch.

Peripheral inflammation is always accompanied by a noxious sensation, either pain or itch, providing a protective warning for the occurrence of pathological changes; however, the mechanisms determining whether pain, itch, or both will be elicited under certain inflammatory statuses are still far from clear. Complete Freund's adjuvant (CFA) contains heat killed and dried Mycobacterium tuberculosis widely used to induce inflammatory pain models, but how CFA treatment affects itch sensation and the possible mechanisms are still unclear. In this study, using itch behavior testing and calcium imaging, we showed that both the behaviors and calcium responses associated with Transient Receptor Potential Vanilloid 1 (TRPV1)-mediated histamine-dependent itch and Transient Receptor Potential Ankyrin 1 (TRPA1)-mediated histamine-independent itch were significantly suppressed by CFA treatment. Furthermore, to explore the possible cellular mechanisms, high-throughput single-cell RNA sequencing and real-time PCR were used to detect CFA-induced changes of itch-related genes in dorsal root ganglion (DRG) neurons. Our results revealed that although both nociceptive Trpv1+ and Trpa1+ DRG neurons were increased after CFA treatment, most known pruriceptors, including Hrh1+, Mrgpra3+, Mrgprd+, Htr3a+, Htr1f+, IL31ra+, Osmr+, and Lpar3+ DRG neurons, were significantly decreased, which may explain that CFA treatment caused itch suppression. This study indicated that itch sensation was affected after CFA treatment, although negatively, and comprehensive but not specific suppression of different pruriceptors was observed after CFA treatment, suggesting that a unified adaptive change of increased pain and decreased itch will occur simultaneously under CFA-induced inflammatory conditions.

Hypothalamic paraventricular nucleus neurons activated by estrogen GPER1 receptors promote anti-inflammation effects in the early stage of colitis.

The hypothalamus-pituitary-adrenal (HPA) axis is known to mediate gut-brain interaction, and the pathological inflammatory process in the intestine can induce HPA axis involved 'fight or flight' response to suppress or facilitate intestinal inflammation. Hypothalamic paraventricular nucleus (PVN) neurons are responsible for controlling the HPA axis activity, but their exact role in modulating intestinal inflammation remains unclear. In this study, we used the dextran sulfate sodium (DSS)-induced mice colitis model, gene editing, and RNA interference to determine the effects of PVN neurons on intestinal inflammation. We found that at the early stage (third day) after DSS treatment, there was a mild inflammation in the colorectal area and an increased neuron activation in the PVN but not in the adjacent area. At the same time, ~80% of activated PVN neurons also expressed novel estrogen GPER1 receptor. The colitis noticeably worsened in GPER1-knockout mice and local PVN GPER1-knockdown mice. These results indicated that PVN GPER1 positive neurons potentially have a protective function during the early stages of DSS-induced colitis, and this may be a mechanism by which the central nervous system attempts to suppress intestinal inflammation to achieve self-protection.

Cancer Exacerbates Ischemic Brain Injury Via Nrp1 (Neuropilin 1)-Mediated Accumulation of Regulatory T Cells Within the Tumor.

Background and Purpose- Adoptive transfer of regulatory T cells (Tregs) protect against stroke; however, Treg-based therapy raises concerns in stroke patients with cancer because of the immunosuppressive function of Tregs. The purpose of this study was to investigate the role of Tregs in cerebral ischemic brain injury with concomitant cancer. Methods- To establish a cancer phenotype, MC38 colon cancer or B16 melanoma cells (5×105/mice) were injected subcutaneously into C57BL/6J mice 2 to 3 weeks before distal middle cerebral artery occlusion surgery. Infarct volume, neuroinflammation, and Tregs infiltration were measured by 2,3,5-triphenyltetrazolium chloride staining, immunofluorescence staining, real-time polymerase chain reaction, and flow cytometry. Mechanistically, Nrp1 (neuropilin-1) monoclonal antibody was used to block the Nrp1 effect on Tregs ex vivo before being transferred into recombination activating gene 1 (Rag1-/-) stroke mice, which are devoid of T and B cells, or a Nrp1 neutralization antibody was injected systemically into cancer-bearing wild-type mice after stroke. Results- Cancer-bearing mice with stroke exhibited augmented neuroinflammation and fewer Tregs in the brain, but more infiltration of Tregs to the tumor was apparent after distal middle cerebral artery occlusion. Depletion of Tregs increased infarct volume in stroke mice but did not further exacerbate brain injury in cancer-bearing stroke mice. Nrp1 blocking ex vivo or Nrp1 systemic neutralization attenuated ischemic brain injury and reversed accumulation of Tregs within tumor after stroke in cancer-bearing mice. Conclusions- Nrp1 signaling mediated accumulation of Tregs within tumor might play a critical role in exacerbating ischemic brain injury in cancer-bearing mice and may represent a promising immune modulatory target for the combined condition of cancer and stroke.

Lipopolysaccharide induced the proliferation of mouse lung fibroblasts by suppressing FoxO3a/p27 pathway.

Aberrant aggregation and activation of lung fibroblasts is a key process in pulmonary fibrosis, but the underlying mechanism remains enigmatic. Forkhead Box O3a (FoxO3a) is considered to be an important transcription factor that could regulate both cell cycle and cell viability. To investigate the role of FoxO3a on LPS-induced lung fibroblast proliferation, we transfected FoxO3a-SiRNA or FoxO3a-OE lentivirus into cultured mouse lung fibroblasts to knockdown or overexpress FoxO3a and pretreated mouse lung fibroblasts with gefitinib to enhance FoxO3a activity. The proliferation of lung fibroblasts was evaluated by CCK8 assay, the expression of FoxO3a, phosphorylated FoxO3a (p-FoxO3a) and p27 were measured by Western blot. We found that the proliferation of mouse lung fibroblasts mediated by LPS is accompanied by the inactivation of FoxO3a. The knockdown of FoxO3a could further decreased the expression of p27 mediated by LPS, while the overexpression of FoxO3a significantly increased the expression of p27 and suppressed LPS-induced lung fibroblast proliferation. Upon treating fibroblasts with gefitinib, the phosphorylation of FoxO3a was reduced and FoxO3a translocated into the nucleus, the expression of p27 was significantly increased and the proliferation of lung fibroblasts mediated by LPS could also be inhibited effectively. The results indicate that overexpression and reduced phosphatase activity of FoxO3a inhibit LPS-induced lung fibroblast proliferation through the activation of FoxO3a/p27 signaling pathways. Thus, to enhance FoxO3a activity could be a potential therapeutic target for LPS-induced pulmonary fibrosis.

Divergent Effect of Dezocine, Morphine and Sufentanil on Intestinal Motor Function in Rats.

BACKGROUND: Opioid induced bowel dysfunction is the most common side effect of preoperatively administrated morphine, fentanyl and its derivative. However, the influence of dezocine on intestinal mobility is rarely reported. This study was designed to investigate the effects of dezocine, morphine and sufentanil on both intestinal smooth muscle contraction and propulsion in rats. METHODS: Contractile tension and frequency of isolated rat small intestine smooth muscle were measured using tension transducer after incubation with different concentrations of dezocine, morphine and sufentanil. The propulsive rate of methylene blue in rat intestinal tract was measured 30 minutes after intraperitoneal injection of morphine, sufentanil and dezocine. Percent of change in contractile tension and contraction frequency compared to baseline level were calculated to evaluate muscle contraction. Propulsive rate of methylene blue was calculated as the percentage of methylene blue moving distance in intestinal tract compared to the length of the small intestine. RESULTS: Morphine and sufentanil significantly increased the contractile tension of isolated small intestine smooth muscle at high doses. The contraction frequency did not change significantly among the 3 tested doses. Increasing the dose of dezocine from 1.7 mg.L(-1) to 10.2 mg.L(-1) did not change either the contractile tension or the contraction frequency. The propulsive rate of methylene blue in intestinal tract was significantly decreased after the treatment with morphine, sufentanil and dezocine (45.6%, 43.7%, and 42.1% respectively) compared to control group(57.1%), while the difference among the 3 drug groups were not significant. CONCLUSION: Morphine and sufentanil may dose dependently increase the contractile tension and contraction ability of isolated rat small intestine smooth muscle, while dezocine has no significant effect on intestine smooth muscle contraction. However, all these opioids might impair small intestinal propulsion.

Perioperative stroke deteriorates white matter integrity by enhancing cytotoxic CD8+ T-cell activation.

AIM: To explore the regulatory mechanisms of microglia-mediated cytotoxic CD8+ T-cell infiltration in the white matter injury of perioperative stroke (PIS). METHODS: Adult male C57BL/6 mice were subjected to ileocolic bowel resection (ICR) 24 h prior to permanent distant middle cerebral artery occlusion (dMCAO) to establish model PIS. White matter injury, functional outcomes, peripheral immune cell infiltration, and microglia phenotype were assessed up to 28 days after dMCAO using behavioral phenotyping, immunofluorescence staining, transmission electron microscopy, western blot, and FACS analysis. RESULTS: We found surgery aggravated white matter injury and deteriorated sensorimotor deficits up to 28 days following PIS. The PIS mice exhibited significantly increased activation of peripheral and central CD8+ T cells, while significantly reduced numbers of mature oligodendrocytes compared to IS mice. Neutralizing CD8+ T cells partly reversed the aggravated demyelination following PIS. Pharmacological blockage or genetic deletion of receptor-interacting protein kinase 1 (RIPK1) activity could alleviate CD8+ T-cell infiltration and demyelination in PIS mice. CONCLUSION: Surgery exacerbates demyelination and worsens neurological function by promoting infiltration of CD8+ T cells and microglia necroptosis, suggesting that modulating interactions of CD8+ T cells and microglia could be a novel therapeutic target of long-term neurological deficits of PIS.

Increase of beta-amyloid and C-reactive protein in liver transplant recipients with postoperative cognitive dysfunction.

BACKGROUND: Postoperative cognitive dysfunction (POCD) is an adverse condition characterized by declined cognitive functions following surgeries and anesthesia. POCD has been associated with increased hospital stay and mortality. There are histological similarities to Alzheimer's disease. Most early studies were conducted in patients receiving cardiac surgery. Since there is no information about POCD in liver transplant recipients, we measured the incidence of POCD in patients after liver transplantation and examined the correlation between neurological dysfunction and biological markers of dementia-based diseases. METHODS: We studied 25 patients who had a liver transplan-tation between July 2008 and February 2009. Patients with prior encephalopathy or risk factors associated with the development of POCD were excluded from the study. Five validated neuropsychiatric tests were used for diagnosis. The diagnosis was based on one standard deviation decline in two of the five neuropsychiatric tests. The correlation between patient variables and the development of POCD was examined. Serum levels of beta-amyloid and C-reactive protein were measured by standard ELISA and compared between patients with and without POCD. RESULTS: POCD was present in 11 (44%) of the 25 patients. Patients with POCD had significantly higher MELD scores, were more often Child-Pugh class C and received more blood transfusion during surgery. The serum beta-amyloid protein and C-reactive protein concentrations were significantly increased at 24 hours after surgery in the POCD group. CONCLUSIONS: The incidence of POCD in our group of liver transplant patients was greater than that reported in other surgical patients. The increase in the serum biomarkers of dementia in the POCD patients supports the hypothesis that chronic cognitive defects are due to a process similar to that seen in Alzheimer's disease.

The locus coeruleus input to the rostral ventromedial medulla mediates stress-induced colorectal visceral pain.

Unlike physiological stress, which carries survival value, pathological stress is widespread in modern society and acts as a main risk factor for visceral pain. As the main stress-responsive nucleus in the brain, the locus coeruleus (LC) has been previously shown to drive pain alleviation through direct descending projections to the spinal cord, but whether and how the LC mediates pathological stress-induced visceral pain remains unclear. Here, we identified a direct circuit projection from LC noradrenergic neurons to the rostral ventromedial medulla (RVM), an integral relay of the central descending pain modulation system. Furthermore, the chemogenetic activation of the LC-RVM circuit was found to significantly induce colorectal visceral hyperalgesia and anxiety-related psychiatric disorders in naïve mice. In a dextran sulfate sodium (DSS)-induced visceral pain model, the mice also presented colorectal visceral hypersensitivity and anxiety-related psychiatric disorders, which were associated with increased activity of the LC-RVM circuit; LC-RVM circuit inhibition markedly alleviated these symptoms. Furthermore, the chronic restraint stress (CRS) model precipitates anxiety-related psychiatric disorders and induces colorectal visceral hyperalgesia, which is referred to as pathological stress-induced hyperalgesia, and inhibiting the LC-RVM circuit attenuates the severity of colorectal visceral pain. Overall, the present study clearly demonstrated that the LC-RVM circuit could be critical for the comorbidity of colorectal visceral pain and stress-related psychiatric disorders. Both visceral inflammation and psychological stress can activate LC noradrenergic neurons, which promote the severity of colorectal visceral hyperalgesia through this LC-RVM circuit.

Preoperative Pain Facilitates Postoperative Cognitive Dysfunction via Periaqueductal Gray Matter-Dorsal Raphe Circuit.

Postoperative cognitive dysfunction (POCD) is a medically induced, rapidly occurring postoperative disease, which is hard to recover and seriously threatens the quality of life, especially for elderly patients, so it is important to identify the risk factors for POCD and apply early intervention to prevent POCD. As we have known, pain can impair cognition, and many surgery patients experience different preoperative pain, but it is still unknown whether these patients are vulnerable for POCD. Here we found that chronic pain (7 days, but not 1 day acute pain) induced by Complete Freund's Adjuvant (CFA) injected in the hind paw of rats could easily induce spatial cognition and memory impairment after being exposed to sevoflurane anesthesia. Next, for the mechanisms, we focused on the Periaqueductal Gray Matter (PAG), a well-known pivotal nucleus in pain process. It was detected the existence of neural projection from ventrolateral PAG (vlPAG) to adjacent nucleus Dorsal Raphe (DR), the origin of serotonergic projection for the whole cerebrum, through virus tracing and patch clamp recordings. The Immunofluorescence staining and western blot results showed that Tryptophan Hydroxylase 2 (TPH2) for serotonin synthesis in the DR was increased significantly in the rats treated with CFA for 7 days and sevoflurane for 3 hours, while chemo-genetic inhibition of the vlPAG-DR projection induced obvious spatial learning and memory impairment. Our study suggests that preoperative chronic pain may facilitate cognitive function impairment after receiving anesthesia through the PAG-DR neural circuit, and preventative analgesia should be a considerable measure to reduce the incidence of POCD.

Molecular identification of bulbospinal ON neurons by GPER, which drives pain and morphine tolerance.

The rostral ventromedial medulla (RVM) exerts bidirectional descending modulation of pain attributable to the activity of electrophysiologically identified pronociceptive ON and antinociceptive OFF neurons. Here, we report that GABAergic ON neurons specifically express G protein-coupled estrogen receptor (GPER). GPER+ neurons exhibited characteristic ON-like responses upon peripheral nociceptive stimulation. Optogenetic activation of GPER+ neurons facilitated, but their ablation abrogated, pain. Furthermore, activation of GPER caused depolarization of ON cells, potentiated pain, and ameliorated morphine analgesia through desensitizing µ-type opioid receptor-mediated (MOR-mediated) activation of potassium currents. In contrast, genetic ablation or pharmacological blockade of GPER attenuated pain, enhanced morphine analgesia, and delayed the development of morphine tolerance in diverse preclinical pain models. Our data strongly indicate that GPER is a marker for GABAergic ON cells and illuminate the mechanisms underlying hormonal regulation of pain and analgesia, thus highlighting GPER as a promising target for the treatment of pain and opioid tolerance.

Indispensable role of ß-arrestin2 in the protection of remifentanil preconditioning against hepatic ischemic reperfusion injury.

Our previous study demonstrated that remifentanil, an opioid agonist, conferred profound liver protection during hepatic ischemia reperfusion injury (HIRI), in which Toll-like receptors (TLRs) played a crucial role in mediating the inflammatory responses. ß-arrestin2, a well-known mu opioid receptor desensitizer, is also a negatively regulator of Toll-like receptor 4 (TLR4)-mediated inflammatory reactions in a mitogen-activated protein kinase (MAPK)-dependent manner. Using the rodent models of hepatic ischemia reperfusion injury both in wild type and TLR4 knockout (TLR4 KO) mice, we found that remifentanil preconditioning could inhibit the expression of TLR4 and reduce the inflammatory response induced by HIRI in wild type but not in TLR4 KO mice. For the in-vitro study, LPS was used to treat RAW264.7 macrophage cells to mimic the inflammatory response induced by HIRI. Remifentanil increased ß-arrestin2 expression both in vivo and in vitro, while after silencing ß-arrestin2 RNA, the effect of remifentanil in reducing cell death and apoptosis, as well as decreasing phosphorylation of ERK and JNK were abolished in RAW264.7 cells. These data suggested that remifentanil could ameliorate mice HIRI through upregulating ß-arrestin2 expression, which may function as a key molecule in bridging opioid receptor and TLR4 pathway.

Rosiglitazone ameliorates tissue plasminogen activator-induced brain hemorrhage after stroke.

OBJECTIVE: Delayed thrombolytic therapy with recombinant tissue plasminogen activator (tPA) may exacerbate blood-brain barrier (BBB) breakdown after ischemic stroke and lead to catastrophic hemorrhagic transformation (HT). Rosiglitazone(RSG), a widely used antidiabetic drug that activates peroxisome proliferator-activated receptor-γ (PPAR-γ), has been shown to protect against cerebral ischemia through promoting poststroke microglial polarization toward the beneficial anti-inflammatory phenotype. However, whether RSG can alleviate HT after delayed tPA treatment remains unknown. In this study, we sort to examine the role of RSG on tPA-induced HT after stroke. METHODS AND RESULTS: We used the murine suture middle cerebral artery occlusion (MCAO) models of stroke followed by delayed administration of tPA (10 mg/kg, 2 hours after suture occlusion) to investigate the therapeutic potential of RSG against tPA-induced HT. When RSG(6 mg/kg) was intraperitoneally administered 1 hour before MCAO in tPA-treated MCAO mice, HT in the ischemic territory was significantly attenuated 1 day after stroke. In the tPA-treated MCAO mice, we found RSG significantly mitigated BBB disruption and hemorrhage development compared to tPA-alone-treated stroke mice. Using flow cytometry and immunostaining, we confirmed that the expression of CD206 was significantly upregulated while the expression of iNOS was down-regulated in microglia of the RSG-treated mice. We further found that the expression of Arg-1 was also upregulated in those tPA and RSG-treated stroke mice and the protection against tPA-induced HT and BBB disruption in these mice were abolished in the presence of PPAR-γ antagonist GW9662 (4 mg/kg, 1 hour before dMCAO through intraperitoneal injection). CONCLUSIONS: RSG treatment protects against BBB damage and ameliorates HT in delayed tPA-treated stroke mice by activating PPAR-γ and favoring microglial polarization toward anti-inflammatory phenotype.

IL-2mAb reduces demyelination after focal cerebral ischemia by suppressing CD8+ T cells.

AIMS: Demyelination, one of the major pathological changes of white matter injury, is closely related to T-cell-mediated immune responses. Thus, we investigate the role of an IL-2 monoclonal antibody (IL-2mAb, JES6-1) in combatting demyelination during the late phase of stroke. METHODS: IL-2mAb or IgG isotype antibody (0.25 mg/kg) was injected intraperitoneally 2 and 48 hours after middle cerebral artery occlusion (MCAO) surgery. Infarct volume, peripheral immune cell infiltration, microglia activation, and myelin loss were measured by 2,3,5-triphenyte trazoliumchloride staining, immunofluorescence staining, flow cytometry, and Western blot. Intraperitoneal CD8 neutralizing antibody (15 mg/kg) was injected 1 day before MCAO surgery to determine the role of CD8+ T cells on demyelinating lesions. RESULTS: IL-2mAb treatment reduced brain infarct volume, attenuated demyelination, and improved long-term sensorimotor functions up to 28 days after dMCAO. Brain infiltration of CD8+ T cells and peripheral activation of CD8+ T cells were both attenuated in IL-2 mAb-treated mice. The protection of IL-2mAb on demyelination was abolished in mice depleted of CD8+ T cell 1 week after stroke. CONCLUSIONS: IL-2mAb preserved white matter integrity and improved long-term sensorimotor functions following cerebral ischemic injury. The activation and brain infiltration of CD8+ T cells are detrimental for demyelination after stroke and may be the major target of IL-2mAb posttreatment in the protection of white matter integrity after stroke.

Coregulation of endoplasmic reticulum stress and oxidative stress in neuropathic pain and disinhibition of the spinal nociceptive circuitry.

The accumulation of unfolded or misfolded proteins in the endoplasmic reticulum (ER) lumen leads to ER stress, which is related to cellular reactive oxygen species production. Neuropathic pain may result from spinal dorsal horn (SDH) ER stress. In this study, we examined the cause-effect relationship between ER stress and neuropathic pain using the spinal nerve ligation (SNL) rat model. We showed that ER stress was mutually promotive with oxidative stress during the process. We also tested the hypothesis that spinal sensitization arose from reduced activities of GABA-ergic interneurons and that spinal sensitization was mediated by SDH ER stress. Other important findings in this study including the following: (1) nociceptive behavior was alleviated in SNL rat as long as tauroursodeoxycholic acid injections were repeated to inhibit ER stress; (2) inducing SDH ER stress in healthy rat resulted in mechanical hyperalgesia; (3) blocking protein disulfide isomerase pharmacologically reduced ER stress and nociceptive behavior in SNL rat; (4) cells in the dorsal horn with elevated ER stress were mainly neurons; and (5) whole-cell recordings made in slide preparations revealed significant inhibition of GABA-ergic interneuron activity in the dorsal horn with ER stress vs in the healthy dorsal horn. Taken together, results of the current study demonstrate that coregulation of ER stress and oxidative stress played an important role in neuropathic pain process. Inhibiting SDH ER stress could be a potential novel strategy to manage neuropathic pain.

Increased Renal Clearance of Rocuronium Compensates for Chronic Loss of Bile Excretion, via upregulation of Oatp2.

Requirement for rocuronium upon surgery changes only minimally in patients with end-stage liver diseases. Our study consisted of both human and rat studies to explore the reason. The reduction rate of rocuronium infusion required to maintain neuromuscular blockade during the anhepatic phase (relative to paleohepatic phase) was examined in 16 children with congenital biliary atresia receiving orthotopic liver transplantation. Pharmacodynamics and pharmacokinetics of rocuronium were studied based on BDL rats. The role of increased Oatp2 and decrease Oatp1 expressions in renal compensation were explored. The reduction of rocuronium requirements significantly decreased in obstructively jaundiced children (24 ± 9 vs. 39 ± 11%). TOF50 in BDL rats was increased by functional removal of the kidneys but not the liver, and the percentage of rocuronium excretion through urine increased (20.3 ± 6.9 vs. 8.6 ± 1.8%), while that decreased through bile in 28d-BDL compared with control group. However, this enhanced renal secretion for rocuronium was eliminated by Oatp2 knock-down, rather than Oatp1 overexpression (28-d BDL vs. Oatp1-ShRNA or Oatp2-ShRNA, 20.3 ± 6.9 vs. 17.0 ± 6.6 or 9.3 ± 3.2%). Upon chronic/sub-chronic loss of bile excretion, rocuronium clearance via the kidneys is enhanced, by Oatp2 up-regulation.

Hippocampus bcl-2 and bax expression and neuronal apoptosis after moderate hypothermic cardiopulmonary bypass in rats.

Using a rat model of moderate hypothermic (26 degrees C-28 degrees C) cardiopulmonary bypass (CPB) with hemodilution, we investigated hippocampal apoptotic gene expression and neuronal apoptosis up to 6 h after CPB. The CPB was performed on male rats (380-400 g) under general anesthesia with isoflurane and fentanyl. The right atrium and tail artery were cannulated, and a peristaltic pump and membrane oxygenator were used for CPB. Two groups were studied: Group 1 consisted of fasted rats (n = 15) subjected to 60 min of moderate hypothermic nonpulsatile CPB; Group 2 consisted of sham-operated rats (n = 15). At 1 h after CPB, in 6 rats per group, hippocampus was processed for the apoptotic gene (bcl-2 and bax) messenger RNAs detection by reverse transcriptase polymerase chain reaction, and messenger RNA expression was determined by the ratio of the polymerase chain reaction product of bcl-2 or bax to the beta-actin gene. At 6 h after CPB, in 6 rats per group, hippocampus expression of Bcl-2 and bax protein was determined by immunohistochemistry, and neuronal apoptosis was detected by TUNEL. At 6 h after CPB, in three rats per group, changes in hippocampal CA1 neuronal ultra structure were determined with electron microscopy. Group 1 had increased ratios of bcl-2/beta-actin, bax/beta-actin, and bax/bcl-2 mRNA at 1 h after CPB (bcl-2/beta-actin, 0.82 +/- 0.14 versus 0.63 +/- 0.07; P = 0.03; bax/beta-actin, 1.04 +/- 0.14 versus 0.56 +/- 0.03; P = 0.00; bax/bcl-2, 1.31 +/- 0.12 versus 0.84 +/- 0.09; P = 0.02; Group 1 versus Group 2, respectively). Group 1 had increased bcl-2 and bax protein expression in hippocampal CA1 region at 6 h after CPB (bcl-2, 0.18 +/- 0.05 versus 0.09 +/- 0.01; P = 0.02; bax, 0.20 +/- 0.06 versus 0.04 +/- 0.02; P = 0.01; Group 1 versus Group 2, respectively). Group 1 had increased TUNEL staining in hippocampus CA1 at 6 h after CPB (0.14 +/- 0.02 versus 0.03 +/- 0.01; P = 0.00; Group 1 versus Group 2, respectively). In Group 1 CA1 hippocampus neurons, ultra-structural changes consistent with apoptosis occurred. In rats, moderate hypothermic CPB with hemodilution is associated with CA1 hippocampus bax and bcl-2 gene expression and neuronal apoptosis during the early post-CPB recovery period.

Overexcited MaxiK and KATP channels underlie obstructive jaundice-induced vasoconstrictor hyporeactivity of arterial smooth muscle.

Substantial evidence has shown that obstructive jaundice can induce vascular hyporesponsiveness. The present study was designed to investigate mechanisms of MaxiK channel and KATP underlying cholestasis-induced vascular dysfunction. The isolated thoracic aorta was used to explore norepinephrine (NE)-induced contraction. The function of MaxiK and KATP channels were investigated using whole-cell patch clamp recording. Compared with Sham group, NE-induced vascular contraction was blunted after bile duct ligation (BDL), which could not be ameliorated significantly after endothelial denudation. Charybdotoxin and glibenclamide induced a more pronounced recovery from vascular hyporesponsiveness to NE in BDL group compared with Sham group. BDL significantly promoted the charybdotoxin sensitive MaxiK current and KATP current in isolated aortic smooth muscle cells. In addition, the expression of auxiliary subunits (MaxiK-ß1 and SUR2B) rather pore-forming subunits (MaxiK-α and Kir6.1) was significantly up-regulated after BDL. These findings suggest that MaxiK and KATP channels play an important role in regulating vascular hyporesponsiveness in BDL rats.