Changes in TRPV1 Receptor, CGRP, and BDNF Expression in Rat Dorsal Root Ganglion with Resiniferatoxin-Induced Neuropathic Pain: Modulation by Pulsed Radiofrequency Applied to the Sciatic Nerve.

Pulsed radiofrequency (PRF) is a safe method of treating neuropathic pain by generating intermittent electric fields at the needle tip. Resiniferatoxin (RTX) is an ultrapotent agonist of transient receptor potential vanilloid subtype-1 (TRPV1) receptors. We investigated the mechanism of PRF using a rat model of RTX-induced neuropathic pain. After administering RTX intraperitoneally, PRF was applied to the right sciatic nerve. We observed the changes in TRPV1, calcitonin gene-related peptide (CGRP), and brain-derived neurotrophic factor (BDNF) in the dorsal root ganglia by western blotting. Expressions of TRPV1 and CGRP were significantly lower in the contralateral (RTX-treated, PRF-untreated) tissue than in control rats (p<0.0001 and p<0.0001, respectively) and the ipsilateral tissues (p<0.0001 and p<0.0001, respectively). BDNF levels were significantly higher in the contralateral tissues than in the control rats (p<0.0001) and the ipsilateral tissues (p<0.0001). These results suggest that, while TRPV1 and CGRP are decreased by RTX-induced neuronal damage, increased BDNF levels result in pain development. PRF may promote recovery from neuronal damage with concomitant restoration of TRPV1 and CGRP, and exert its analgesic effect by reversing BDNF increase. Further research is required to understand the role of TRPV1 and CGRP restoration in improving mechanical allodynia.

Epidural Anesthesia and Continuous Epidural Analgesia in a Pediatric Patient With Pelizaeus-Merzbacher Disease: A Case Report.

Pelizaeus-Merzbacher disease (PMD) is a genetic leukodystrophy, which is a progressive and degenerative central nervous system abnormality caused by dysmyelination. Because the incidence of PMD is extremely low, only a few case reports have been published regarding its anesthetic management. In particular, epidural anesthesia has only been reported in one case of general anesthesia combined with caudal anesthesia. We performed general anesthesia combined with epidural anesthesia for the soft-tissue release surgery for bilateral hip subluxation in a six-year-old male patient diagnosed with PMD. General anesthesia was induced with sevoflurane in nitrous oxide and oxygen. Rocuronium was administered to facilitate tracheal intubation. After intubation, general anesthesia was maintained with sevoflurane in the air and oxygen. An epidural catheter was placed from L3/4. For epidural anesthesia and analgesia, 1% mepivacaine was used as needed, and 2 ml/h of 0.2% ropivacaine was started one hour before the end of surgery. During surgery, only epidural analgesia was provided as postoperative analgesia, and the patient did not complain of pain after extubation. Anesthesia lasted three hours and 55 minutes. No significant hemodynamic or respiratory changes occurred. Postoperatively, the patient received continuous epidural analgesia and regular oral acetaminophen, and pain control was good. The epidural catheter was removed on the second postoperative day. The postoperative course was good, and the patient was transferred to a pediatric rehabilitation hospital on the fifth postoperative day. No adverse events occurred and no neurological deficits were observed during hospitalization. In conclusion, anesthesiologists should pay attention to the possibility of perioperative aspiration, spasticity, and seizure, even with mild PMD. Proper preoperative evaluations, intraoperative monitoring, and anesthetic techniques will ensure safe anesthesia for PMD patients. Although regional anesthesia in patients with pre-existing neurologic deficits is controversial, we were able to safely perform epidural anesthesia and postoperative continuous epidural analgesia in a pediatric patient with PMD.

Selective optogenetic activation of NaV1.7-expressing afferents in NaV1.7-ChR2 mice induces nocifensive behavior without affecting responses to mechanical and thermal stimuli.

In small and large spinal dorsal root ganglion neurons, subtypes of voltage-gated sodium channels, such as NaV1.7, NaV1.8, and NaV1.9 are expressed with characteristically localized and may play different roles in pain transmission and intractable pain development. Selective stimulation of each specific subtype in vivo may elucidate its role of each subtype in pain. So far, this has been difficult with current technology. However, Optogenetics, a recently developed technique, has enabled selective activation or inhibition of specific neural circulation in vivo. Moreover, optogenetics had even been used to selectively excite NaV1.8-expressing dorsal root ganglion neurons to induce nocifensive behavior. In recent years, genetic modification technologies such as CRISPR/Cas9 have advanced, and various knock-in mice can be easily generated using such technology. We aimed to investigate the effects of selective optogenetic activation of NaV1.7-expressing afferents on mouse behavior. We used CRISPR/Cas9-mediated homologous recombination to generate bicistronic NaV1.7-iCre knock-in mice, which express iCre recombinase under the endogenous NaV1.7 gene promoter without disrupting NaV1.7. The Cre-driver mice were crossed with channelrhodopsin-2 (ChR2) Cre-reporter Ai32 mice to obtain NaV1.7iCre/+;Ai32/+, NaV1.7iCre/iCre;Ai32/+, NaV1.7iCre/+;Ai32/Ai32, and NaV1.7iCre/iCre;Ai32/Ai32 mice. Compared with wild-type mice behavior, no differences were observed in the behaviors associated with mechanical and thermal stimuli exhibited by mice of the aforementioned genotypes, indicating that the endogenous NaV1.7 gene was not affected by the targeted insertion of iCre. Blue light irradiation to the hind paw induced paw withdrawal by mice of all genotypes in a light power-dependent manner. The threshold and incidence of paw withdrawal and aversive behavior in a blue-lit room were dependent on ChR2 expression level; the strongest response was observed in NaV1.7iCre/iCre;Ai32/Ai32 mice. Thus, we developed a non-invasive pain model in which peripheral nociceptors were optically activated in free-moving transgenic NaV1.7-ChR2 mice.

Extracellular signal-regulated kinase phosphorylation enhancement and NaV1.7 sodium channel upregulation in rat dorsal root ganglia neurons contribute to resiniferatoxin-induced neuropathic pain: The efficacy and mechanism of pulsed radiofrequency therapy.

Pulsed radiofrequency (PRF) therapy is one of the most common treatment options for neuropathic pain, albeit the underlying mechanism has not been hitherto elucidated. In this study, we investigated the efficacy and mechanism of PRF therapy on resiniferatoxin (RTX)-induced mechanical allodynia, which has been used as a model of postherpetic neuralgia (PHN). Adult male rats were intraperitoneally injected with a vehicle or RTX. Furthermore, PRF current was applied on a unilateral sciatic nerve in all RTX-treated rats. On both ipsilateral and contralateral sides, the paw mechanical withdrawal thresholds were examined and L4-6 dorsal root ganglia (DRG) were harvested. In the DRG of rats with RTX-induced mechanical allodynia, NaV1.7, a voltage-gated Na+ channel, was upregulated following the enhancement of extracellular signal-regulated kinase phosphorylation. Early PRF therapy, which was applied 1 week after RTX exposure, suppressed this NaV1.7 upregulation and showed an anti-allodynic effect; however, late PRF therapy, which was applied after 5 weeks of RTX exposure, failed to inhibit allodynia. Interestingly, late PRF therapy became effective after daily tramadol administration for 7 days, starting from 2 weeks after RTX exposure. Both early PRF therapy and late PRF therapy combined with early tramadol treatment suppressed NaV1.7 upregulation in the DRG of rats with RTX-induced mechanical allodynia. Therefore, NaV1.7 upregulation in DRG is related to the development of RTX-induced neuropathic pain; moreover, PRF therapy may be effective in the clinical management of patients with PHN via NaV1.7 upregulation inhibition.

Effect of cryoprecipitate on an increase in fibrinogen level in patients with excessive intraoperative blood loss: a single-center retrospective study.

BACKGROUND: Cryoprecipitate, which contains fibrinogen and factor VIII in large quantities, is concentrated from fresh frozen plasma, and it has hemostatic effects in severe bleeding. We retrospectively examined the effects of cryoprecipitate on the increase in fibrinogen levels in patients with excessive intraoperative blood loss. METHODS: Ninety-seven patients who were administered cryoprecipitate during surgery between June 2014 and May 2019 were enrolled in our study and categorized according to the volume of intraoperative blood loss as follows: group A, 2000-5000 mL; group B, 5000-10,000 mL; group C, > 10,000 mL. Data were extracted from electronic medical records and electronic anesthesia records. The primary endpoint was an increase in the fibrinogen level after the administration of cryoprecipitate. RESULTS: Nine patients with no fibrinogen data and four patients with a bleeding volume of less than 2000 mL were excluded; thus, 84 patients (A: n = 36, B: n = 37, C: n = 11) were evaluated. The mean intraoperative blood loss (mL) in groups A, B, and C were 3348 ± 791, 6688 ± 1225, and 14,281 ± 5142, respectively. The fibrinogen levels (mg/dL) before cryoprecipitate administration in groups A, B, and C were 189 ± 94, 113 ± 42, and 83 ± 29, respectively (p < 0.05 among the groups). The increase in fibrinogen level (mg/dL) after cryoprecipitate administration in group C was significantly greater than that in group A (84 ± 34 versus 50 ± 36, p < 0.01). CONCLUSIONS: The results of this study indicate that the effect of cryoprecipitate on the increase in fibrinogen level was most apparent in patients with excessive intraoperative blood loss ≥ 10,000 mL. In addition, most patients with intraoperative blood loss ≥ 5000 mL had fibrinogen levels < 150 mg/dL which improved to ≥ 150 mg/dL after cryoprecipitate administration in approximately 70% of patients. Therefore, cryoprecipitate administration should be considered for patients with hypofibrinogenemia (≤ 150 mg/dL) experiencing severe bleeding (e.g., ≥ 5000 mL) and rapid administration of cryoprecipitate is necessary to maximize the hemostatic effect, especially when the bleeding volume exceeds 10,000 ml.

The usefulness of plasma levels of mature and total adrenomedullin as biomarkers indicating the magnitude of surgical stress responses: A single-center, prospective, observational study.

BACKGROUND AND AIM: Adrenomedullin (AM), a vasodilatory peptide, is known for its pleiotropic actions. AM levels are increased under inflammatory conditions such as sepsis and can be useful as a prognostic biomarker. However, there are only a few reports on the physiological actions of AM in the perioperative period. The aim of this single-center, prospective, and observational study was to investigate the changes in the plasma levels of mature AM (mAM) and total AM (tAM) observed during the perioperative period. In addition, we aimed to determine the association between each AM level and immune-inflammatory parameters to explore the usefulness of AM as a biomarker of the magnitude of surgical stress responses. METHODS: The levels of both mAM and tAM, in addition to the levels of presepsin, interleukin-6, procalcitonin, white blood cell, and C-reactive protein, were measured in blood samples obtained during the perioperative period. Other laboratory data, including sequential organ failure assessment (SOFA) and acute physiology and chronic health evaluation (APACHE) II scores, were obtained from individual clinical records. Correlations between each AM and clinical parameters were determined using Spearman's rank correlation. P<0.05 were considered statistically significant. RESULTS: One hundred and twenty-three perioperative patients scheduled for three types of surgical procedures, including cardiopulmonary bypass surgery, abdominal surgery, and cervical laminoplasty, were included in this study. There was a moderate to strong correlation between each AM and immune-inflammatory parameters, SOFA score, and APACHE II score, as related to surgical trauma. Specifically, the strongest correlation was observed between each AM and SOFA score. CONCLUSIONS: These findings suggest that plasma AM levels may represent the most important inflammatory mediators that are evident in surgical stress responses. RELEVANCE FOR PATIENTS: Since the levels of both tAM and mAM show the same trend, mAM and tAM may be equally used as biomarkers for the evaluation of the physiological status of surgical patients. TRIAL REGISTRATION: This observational study was retrospectively registered with Japanese Clinical Trial Registry "UMIN-CTR" on March 19, 2018, and was given a trial ID number UMIN000031792.

Comparison of opioid local anesthetic combination regimens using the number of self-administrated boluses in patient-controlled epidural analgesia after cesarean section: A retrospective single-center study.

ABSTRACT: The aim of this study was to assess the efficacy of combined opioids by comparing four regimens of patient-controlled epidural analgesia (PCEA) after cesarean section.Parturient patients who underwent elective or emergent cesarean section under combined spinal and epidural anesthesia from April 2013 to March 2016 were retrospectively analyzed. Based on PCEA, they were assigned to one of 4 groups: local anesthetic alone (LA), epidural single morphine administration during surgery followed by local anesthetic alone (M), local anesthetic combined with fentanyl 10 µg/h (F10), or local anesthetic combined with fentanyl 20 µg/h (F20). The primary outcome was the number of PCEA boluses used. Secondary outcomes included the use of rescue analgesia, postoperative nausea and vomiting, and postoperative pruritus.A total of 250 parturients were analyzed. Whereas the number of PCEA boluses in the LA group was significantly higher than in the other combined opioid groups on the day of surgery and postoperative day 1 (LA: 3 [1-6] and 7 [4-9] vs M: 2 [0-4] and 4 [0-7] vs F10: 1 [0-4] and 3 [0-6] vs F20: 1 [0-3] and 2 [0-8], P = .012 and 0.010, respectively), within the combined opioid groups, the number was not significantly different. Significantly fewer patients in the F20 group required rescue analgesia on postoperative day 1 and 2 (25 and 55%) than those in the M (66 and 81%) and F10 (62 and 66%) groups (P < .001 and P = .007, respectively). Postoperative nausea and vomiting and pruritus were significantly higher in the M group (P < .008 and P = .024, respectively).The results of the present study suggest that local anesthetic alone after a single administration of morphine, or local anesthetic combined with fentanyl 10 µg/h would generally be adequate for PCEA, whereas local anesthetic combined with fentanyl 20 µg/h would be suitable for conventional epidural analgesia.

The diagnostic and prognostic value of mature and total adrenomedullin for sepsis: a prospective observational study.

INTRODUCTION: Information about biologically active adrenomedullin (mature AM), a potential new biomarker for sepsis and septic shock, is limited. Here, we investigated the value of mature AM for diagnosis and outcome prediction in sepsis. MATERIAL AND METHODS: Patients admitted to the intensive care unit (ICU) were retrospectively cate-gorised into non-sepsis or sepsis groups, according to the Sepsis-3 definitions. Plasma levels of mature and total (the sum of the levels of intermediate and mature forms) AM were measured, and their usefulness was compared with that of other sepsis biomarkers, such as procalcitonin and presepsin. RESULTS: Of the 98 patients analysed, 42 were assigned to the non-sepsis and 56 to the sepsis group. Mature and total AM levels on admission were significantly higher in patients with than in those without sepsis. The areas under the receiver operating characteristic curves (AUCs) of mature and total AM for diagnosing sepsis were 0.85 and 0.88, whereas those of procalcitonin and presepsin were 0.83 and 0.68, respectively. AUCs of mature and total AM for predicting 28-day mortality in patients with sepsis became significant on day 3 after admission. A good correlation between the AM forms was found, indicating that changes in their plasma levels may directly reflect each other. CONCLUSIONS: Because mature and total AM levels increased significantly in patients with sepsis on admission, both forms may be used as reliable and early biomarkers for diagnosing sepsis according to the Sepsis-3 definitions. However, prediction of 28-day mortality in such patients would require several days of ICU stay.

Upregulation of ERK phosphorylation in rat dorsal root ganglion neurons contributes to oxaliplatin-induced chronic neuropathic pain.

Oxaliplatin is the first-line chemotherapy for metastatic colorectal cancer. Unlike other platinum anticancer agents, oxaliplatin does not result in significant renal impairment and ototoxicity. Oxaliplatin, however, has been associated with acute and chronic peripheral neuropathies. Despite the awareness of these side-effects, the underlying mechanisms are yet to be clearly established. Therefore, in this study, we aimed to understand the factors involved in the generation of chronic neuropathy elicited by oxaliplatin treatment. We established a rat model of oxaliplatin-induced neuropathic pain (4 mg kg-1 intraperitoneally). The paw withdrawal thresholds were assessed at different time-points after the treatment, and a significant decrease was observed 3 and 4 weeks after oxaliplatin treatment as compared to the vehicle treatment (4.4 ± 1.0 vs. 16.0 ± 4.1 g; P < 0.05 and 4.4 ± 0.7 vs. 14.8 ± 3.1 g; P < 0.05, respectively). We further evaluated the role of different mitogen-activated protein kinases (MAPKs) pathways in the pathophysiology of neuropathic pain. Although the levels of total extracellular signal-regulated kinase (ERK) 1/2 in the dorsal root ganglia (DRG) were not different between oxaliplatin and vehicle treatment groups, phosphorylated ERK (p-ERK) 1/2 was up-regulated up to 4.5-fold in the oxaliplatin group. Administration of ERK inhibitor PD98059 (6 µg day-1 intrathecally) inhibited oxaliplatin-induced ERK phosphorylation and neuropathic pain. Therefore, upregulation of p-ERK by oxaliplatin in rat DRG and inhibition of mechanical allodynia by an ERK inhibitor in the present study may provide a better understanding of intracellular molecular alterations associated with oxaliplatin-induced neuropathic pain and help in the development of potential therapeutics.

Intraoperative Single-Dose Intravenous Acetaminophen for Postoperative Analgesia After Skin Laser Irradiation Surgery in Paediatric Patients: A Small Prospective Study.

OBJECTIVE: Acetaminophen is an analgesic that shows efficacy in postoperative pain relief in children. Many drugs such as opioids, non-steroidal anti-inflammatory drugs, and/or acetaminophen have been used in paediatric skin laser irradiation surgery for postoperative pain relief. However, acetaminophen has some advantages over opioids, and opioids are being used less often. We aimed to demonstrate the effectiveness of intravenous (IV) acetaminophen during surgery for postoperative pain in paediatric skin laser irradiation. METHODS: The present study is a small, prospective, double-blinded, randomized controlled trial. Paediatric patients (1-12 years old with an American Society of Anesthesiologists physical Status I and II), scheduled for skin laser irradiation for a nevus or haemangioma between October 2014 and April 2016 were randomized into the acetaminophen (n=9) and placebo (saline, n=8) groups. The observational face scale (FS) and the Behavioural Observational Pain Scale (BOPS) scores were recorded on emergence from anaesthesia, and 1, 2, and 4 hr post-surgery. RESULTS: Patient characteristics were not significantly different except with regard to the irradiation area and surgery time. The observational FS and BOPS scores of the acetaminophen group were lower than those of the placebo group; median (minimum-maximum) at each recording time: 1 (0-2) - 0 (0-2) - 0 (0-1) - 0 (0-2) vs. 2 (0-4) - 0 (0-2) - 0 (0-2) - 0 (0-1) and 1 (0-3) - 1 (0-3) - 1 (0-2) - 0 (0-1) vs. 2 (0-4) - 3 (0-5) - 1 (0-4) - 0 (0-3), p=0.07 and p=0.003, respectively. No differences in post-surgical analgesic use or adverse events were observed. CONCLUSION: In this study, we showed that the IV acetaminophen group had lower observational FS and BOPS scores in the early postoperative period; however, further studies including a large number of patients are required to confirm our findings.

Comparison of the effect of continuous intravenous infusion and two bolus injections of remifentanil on haemodynamic responses during anaesthesia induction: a prospective randomised single-centre study.

BACKGROUND: Remifentanil is an effective drug for protecting against adverse haemodynamic responses to tracheal intubation. We compared the haemodynamic responses during anaesthesia induction between continuous intravenous (IV) infusion and two bolus injections of remifentanil. METHODS: This prospective, randomised, open-label, single-centre study included patients with American Society of Anesthesiologists physical status I-II, scheduled to undergo elective surgery under general anaesthesia. Patients were randomised into two groups based on remifentanil administration type: the continuous IV infusion group (Group C) receiving a 0.3-µg/kg/min remifentanil infusion for 5 min followed by a 0.1-µg/kg/min remifentanil infusion, and the IV bolus group (Group B) receiving a combination of two bolus injections of remifentanil (first bolus of 0.4 µg/kg and second bolus of 0.6 µg/kg after 3 min) and 0.1 µg/kg/min remifentanil. General anaesthesia was induced with 1 mg/kg propofol and 0.6 mg/kg rocuronium 3 min after remifentanil infusion (Group C) or immediately after the first bolus of remifentanil (Group B). Tracheal intubation was performed 4 min after the injection of propofol and rocuronium. Heart rate and non-invasive blood pressure were recorded at 1-min intervals from baseline (i.e., before induction) to 5 min after tracheal intubation. RESULTS: A total of 107 patients were enrolled (Group C, 55; Group B, 52). Normotensive patients with no history of antihypertensive medication use were assigned to the normotensive subgroup (41 each in both groups), while those with hypertension but without a history of antihypertensive medication use were assigned to the untreated hypertensive subgroup (Group C vs. B, n = 7 vs. 4). Finally, patients with a history of antihypertensive medication use were assigned to the treated hypertensive subgroup (7 each in both Groups C and B). No differences in heart rate and blood pressure were observed between Groups C and B within each subgroup. CONCLUSIONS: Haemodynamic responses during anaesthesia induction were similar between continuous infusion and two bolus injections of remifentanil within both normotensive and hypertensive patients with or without medication. TRIAL REGISTRATION: The trial was retrospectively registered with Japanese Clinical Trial Registry "UMIN-CTR" on 20 October 2016 and was given a trial ID number UMIN000024495 .

Up-regulation of NaV1.7 sodium channels expression by tumor necrosis factor-α in cultured bovine adrenal chromaffin cells and rat dorsal root ganglion neurons.

BACKGROUND: Tumor necrosis factor-α (TNF-α) is not only a key regulator of inflammatory response but also an important pain modulator. TNF-α enhances both tetrodotoxin-sensitive (TTX-S) and tetrodotoxin-resistant Na channel currents in dorsal root ganglion (DRG) neurons. However, it remains unknown whether TNF-α affects the function and expression of the TTX-S NaV1.7 Na channel, which plays crucial roles in pain generation. METHODS: We used cultured bovine adrenal chromaffin cells expressing the NaV1.7 Na channel isoform and compared them with cultured rat DRG neurons. The expression of TNF receptor 1 and 2 (TNFR1 and TNFR2) in adrenal chromaffin cells was studied by Semiquantitative reverse transcription-polymerase chain reaction. The effects of TNF-α on the expression of NaV1.7 were examined with reverse transcription-polymerase chain reaction and Western blot analysis. Results were expressed as mean ± SEM. RESULTS: TNFR1 and TNFR2 were expressed in adrenal chromaffin cells, as well as reported in DRG neurons. TNF-α up-regulated NaV1.7 mRNA by 132% ± 9% (N = 5, P = 0.004) in adrenal chromaffin cells, as well as 117% ± 2% (N = 5, P < 0.0001) in DRG neurons. Western blot analysis showed that TNF-α increased NaV1.7 protein up to 166% ± 24% (N = 5, corrected P < 0.0001) in adrenal chromaffin cells, concentration- and time-dependently. CONCLUSIONS: TNF-α up-regulated NaV1.7 mRNA in both adrenal chromaffin cells and DRG neurons. In addition, TNF-α up-regulated the protein expression of the TTX-S NaV1.7 channel in adrenal chromaffin cells. Our findings may contribute to understanding the peripheral nociceptive mechanism of TNF-α.

New insights concerning insulin synthesis and its secretion in rat hippocampus and cerebral cortex: amyloid-ß1-42-induced reduction of proinsulin level via glycogen synthase kinase-3ß.

The reduction of insulin levels in hippocampal areas is associated with Alzheimer's disease. The present study using rat brain explores the mechanisms of insulin synthesis and secretion, as well as amyloid-ß1-42 (Aß(1-42))-induced reduction of proinsulin expression. After confirming the expression of insulin mRNA and proinsulin in rat brain, we visualized and analyzed the motion of insulin secretion in rat hippocampal neurons using pH-sensitive green fluorescent protein (pHluorin) fused to the insulin. In the rat hippocampal neurons expressing insulin-pHluorin, time-lapse confocal laser scanning microscopy revealed the appearance of fluorescent spots induced by depolarization after stimulation with 50 mM KCl. In these fluorescent spots, Ca(2+)-dependent activator protein for secretion 2 (CAPS2), which is the regulator of the dense-core vesicle involving neuronal peptides, was co-localized with insulin-pHluorin. However, Aß(1-42)-induced reduction of proinsulin in rat hippocampal neurons was inhibited by treatment with lithium and transfection with glycogen synthase kinase-3ß (GSK-3ß) siRNA. These results demonstrate that synthesized insulin is secreted from rat hippocampal and cortical neuron's dense-core vesicles, and that activation of GSK-3ß in Aß(1-42)-induced Alzheimer's model hippocampal neurons decreases the insulin synthesis.

Endothelin-1-induced down-regulation of NaV1.7 expression in adrenal chromaffin cells: attenuation of catecholamine secretion and tau dephosphorylation.

Endothelin-1 and voltage-dependent sodium channels are involved in control and suppression of neuropathological factors, which contribute to sculpting the neuronal network. We previously demonstrated that veratridine-induced NaV1.7 sodium channel activation caused intracellular calcium elevation, catecholamine secretion and tau dephosphorylation in adrenal chromaffin cells. The aim of this study was to examine whether endothelin-1 could modulate NaV1.7. Our results indicated that endothelin-1 decreased the protein level of NaV1.7 and the veratridine-induced increase in intracellular calcium. In addition, it also abolished the veratridine-induced dephosphorylation of tau and the phosphorylation of glycogen synthase kinase-3ß and extracellular signal-regulated kinase. These findings suggest that the endothelin-1-induced down-regulation of NaV1.7 diminishes NaV1.7-related catecholamine secretion and dephosphorylation of tau.

Effects of intravenous low-dose recombinant human atrial natriuretic peptide on renal function in the perioperative management for gastrointestinal perforation or ileus: a retrospective single-center study.

PURPOSE: We studied the effectiveness of human atrial natriuretic peptide (hANP) on management of acute kidney injury. METHODS: This retrospective single-center study included 43 patients from January 2007 to February 2010 who had undergone non-elective abdominal surgery for gastrointestinal perforation and ileus. Patients were separated into 2 groups according to whether hANP was administered or not, and 4 subgroups according to whether or not baseline serum creatinine <1.2 mg/dL; normal cre/hANP (-) (n = 22), high cre/hANP (-) (n = 10), normal cre/hANP (+) (n = 4), and high cre/hANP (+) (n = 7). The administration of hANP was started during operation. RESULTS: The administration rate of hANP ranged between 0.02 and 0.05 µg/kg per minute, except for one patient and the average postoperative administration time of hANP was 167 ± 237 h (range, 8-888 h). There were no significant differences in characteristics of patients within four subgroups, except for patient's weight. Serum creatinine in high cre/hANP (+) got to decrease more than high cre/hANP (-). Outcomes such as 28-day mortality were not significantly different among four subgroups. No patients required renal replacement therapy in each subgroup. CONCLUSION: Intravenous low dose of hANP was useful as acute kidney injury management in gastrointestinal perforation and ileus patients undergoing non-elective surgery.

[Anesthesia and perioperative management in a patient with acquired angioedema].

We experienced anesthesia and perioperative management for hysterectomy in a patient with acquired angioedema. Angioedema due to C1 esterase inhibitor (C1-INH) deficiency (loss or dysfunction of C1-INH) is one of the rarest diseases, and is characterized by recurrent episodes of regional hard edema and ascites induced by mechanical stimuli or mental stress. Edema spreads to the subcutaneous and submucosal layer, and laryngeal edema may cause the upper airway obstruction. Tranexamic acid and C1-INH concentrates were administered perioperatively for prophylaxis of attacks, and combined spinal and epidural anesthesia was performed for hysterectomy. We could manage perioperative care without causing edema.

Transcriptional up-regulation of cell surface Na V 1.7 sodium channels by insulin-like growth factor-1 via inhibition of glycogen synthase kinase-3ß in adrenal chromaffin cells: enhancement of 22Na+ influx, 45Ca2+ influx and catecholamine secretion.

Insulin-like growth factor-1 (IGF-1) plays important roles in the regulation of neuronal development. The electrical activity of Na(+) channels is crucial for the regulation of synaptic formation and maintenance/repair of neuronal circuits. Here, we examined the effects of chronic IGF-1 treatment on cell surface expression and function of Na(+) channels. In cultured bovine adrenal chromaffin cells expressing Na(V)1.7 isoform of voltage-dependent Na(+) channels, chronic IGF-1 treatment increased cell surface [(3)H]saxitoxin binding by 31%, without altering the Kd value. In cells treated with IGF-1, veratridine-induced (22)Na(+) influx, and subsequent (45)Ca(2+) influx and catecholamine secretion were augmented by 35%, 33%, 31%, respectively. Pharmacological properties of Na(+) channels characterized by neurotoxins were similar between nontreated and IGF-1-treated cells. IGF-1-induced up-regulation of [(3)H]saxitoxin binding was prevented by phosphatydil inositol-3 kinase inhibitors (LY204002 or wortmannin), or Akt inhibitor (Akt inhibitor IV). Glycogen synthase kinase-3 (GSK-3) inhibitors (LiCl, valproic acid, SB216763 or SB415286) also increased cell surface [(3)H]saxitoxin binding by ∼ 33%, whereas simultaneous treatment of IGF-1 with GSK-3 inhibitors did not produce additive increasing effect on [(3)H]saxitoxin binding. IGF-1 (100 nM) increased Ser(437)-phosphorylated Akt and Ser(9)-phosphorylated GSK-3ß, and inhibited GSK-3ß activity. Treatment with IGF-1, LiCl or SB216763 increased protein level of Na(+) channel α-subunit; it was prevented by cycloheximide. Either treatment increased α-subunit mRNA level by ∼ 48% and accelerated α-subunit gene transcription by ∼ 30% without altering α-subunit mRNA stability. Thus, inhibition of GSK-3ß caused by IGF-1 up-regulates cell surface expression of functional Na(+) channels via acceleration of α-subunit gene transcription.

Insulin-induced neurite-like process outgrowth: acceleration of tau protein synthesis via a phosphoinositide 3-kinase~mammalian target of rapamycin pathway.

Both insulin and tau, promoting neuronal differentiation (neurite outgrowth, neuronal polarity, and myelination) and cell survival, are associated with neurodegenerative disease (e.g., Alzheimer's disease). The aim of this study was to explore relation between insulin-induced activation of insulin signal and expression of tau protein on neurite-like process outgrowth in adrenal chromaffin cells. Primary cultured bovine adrenal chromaffin cells were incubated with insulin to determine whether stimulant of insulin signal could affect tau expression and neurite-like process outgrowth. Chronic treatment with insulin (⩾6h) led neurite-like process outgrowth as well as increased tau protein level by ∼99% in a concentration (EC(50) 5.5nM)- and time-dependent manner, without changing Ser(396)-phosphorylated tau level. The insulin-induced increase of tau protein level was abolished by LY294002 [an inhibitor of phosphoinositide 3-kinase (PI3K)] and rapamycin [an inhibitor of mammalian target of rapamycin (mTOR)], but not by PD98059 and U0126 [two inhibitors of mitogen-activated protein kinase/extracellular signal-regulated kinase (MEK)]. Additionally, insulin-induced increase of tau was blocked by cyclohexamide (an inhibitor of protein synthesis), but not by actinomycin D (an inhibitor of gene transcription). Pulse-label followed by polyacrylamide gel electrophoresis revealed that insulin accelerated tau protein synthesis rate (t(1/2)) from 2.6 to 1.9h. Insulin did not change tau mRNA level. Taken together, these results suggest that insulin-induced activation of PI3K∼mTOR pathway up-regulated tau protein via acceleration of protein synthesis, on which insulin promoted neurite-like process outgrowth.

Dexmedetomidine and clonidine inhibit the function of Na(v)1.7 independent of α(2)-adrenoceptor in adrenal chromaffin cells.

PURPOSE: Besides being administered systemically for sedation and analgesia, α(2)-agonists such as dexmedetomidine and clonidine have been administered with intrathecal, epidural, or perineural injections, leading to an antinociceptive effect at the spinal cord or peripheral nerve level. However, the mechanism for this remains unclear. In the present study, we examined whether dexmedetomidine and clonidine could inhibit the function of tetrodotoxin-sensitive Na(+) channels, which play important roles in the generation of pain. METHODS: Cultured bovine adrenal chromaffin cells expressing the tetrodotoxin-sensitive Na(v)1.7 Na(+) channel isoform were incubated in KRP buffer containing 2 µCi (22)NaCl for 5 min without or with dexmedetomidine or clonidine in the absence or presence of veratridine, α-scorpion venom, ß-scorpion venom, Ptychodiscus brevis toxin-3 or ouabain. Cells were then washed and counted radioactively. RESULTS: Dexmedetomidine and clonidine reduced veratridine-induced (22)Na(+) influx via Na(v)1.7 in a concentration-dependent manner (EC(50) = 50 µM and 530 µM), even in the presence of ouabain, an inhibitor of Na(+), K(+)-ATPase. Dexmedetomidine and clonidine shifted the concentration-response curve of veratridine for (22)Na(+) influx downward without altering the EC(50) of veratridine. Atipamezole and yohimbine, α(2)-antagonists, did not prevent the inhibition of veratridine-induced (22)Na(+) influx by dexmedetomidine. Dexmedetomidine and clonidine combined with lidocaine induced more inhibition of veratridine-induced (22)Na(+) influx than each drug did individually. Atipamezole and yohimbine did not prevent the lidocaine-enhancing effect of dexmedetomidine and clonidine. CONCLUSION: Dexmedetomidine and clonidine inhibit the function of Na(v)1.7 independent of α(2)-adrenoceptor. These results may lead to a deeper understanding of the peripheral antinociceptive effects of α (2)-agonists.

Nav1.7-Ca2+ influx-induced increased phosphorylations of extracellular signal-regulated kinase (ERK) and p38 attenuate tau phosphorylation via glycogen synthase kinase-3beta: priming of Nav1.7 gating by ERK and p38.

In cultured bovine adrenal chromaffin cells expressing Nav1.7 sodium channel isoform, we previously showed that veratridine-induced Na+ influx via Nav1.7 and the subsequent Ca2+ influx via voltage-dependent calcium channels activated protein kinase C-alpha and Akt, which converged on increasing inhibitory Ser9-phosphorylation of glycogen synthase kinase-3beta, decreasing constitutive Ser396-phosphorylation of tau. Here, veratridine increased constitutive Tyr204-phosphorylation of extracellular signal-regulated kinase-1/-2 (ERK1/ERK2) and constitutive Thr180/Tyr182-dual phosphorylation of p38 by approximately 118% (EC50=2.8 microM). Veratridine-induced increased phosphorylation levels of ERK1/ERK2 and p38 were abolished by tetrodotoxin, extracellular Ca2+ removal, or Gö6976 [12-(2-cyanoethyl)-6,7,12,13-tetrahydro-13-methyl-5-oxo-5H-indolo(2,3-a)pyrrolo(3,4-c)-carbazole;Go6976] (protein kinase C-alpha inhibitor). PD98059 (2'-amino-3'-methoxyflavone) (ERK1/ERK2 inhibitor) or SB203580 [4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole] (p38 inhibitor) attenuated veratridine-induced increased phosphorylation of glycogen synthase kinase-3beta and decreased phosphorylation of tau by approximately 54% and approximately 56%, as partial blockade by Gö6976. Additionally, basal constitutive phosphorylation levels of ERK1/ERK2 and p38 were decreased by PD98059 or SB203580, but not by SB216763 [3-(2,4-dichlorophenyl)-4-(1-methyl-1H-indolo-3-yl)-1H-pyrrole-2,5-dione] (glycogen synthase kinase-3beta inhibitor) or extracellular Ca2+ removal. In this condition, PD98059 or SB203580 (but not SB216763 or extracellular Ca2+ removal) inhibited veratridine-induced 22Na+ influx and 45Ca2+ influx, without changing nicotine-induced 22Na+ influx via nicotinic receptor-associated cation channels and nicotine-induced 45Ca2+ influx via voltage-dependent calcium channels. These results suggest that Nav1.7-Ca2+ influx-protein kinase C-alpha pathway activated ERK1/ERK2 and p38, which increased phosphorylation of glycogen synthase kinase-3beta, decreasing tau phosphorylation. In veratridine-nontreated cells, basal constitutive activities of ERK1/ERK2 and p38 primed Nav1.7 to increase 22Na+ influx.