Study of electrophysiological mechanism of dopamine inhibiting insulin secretion by Kv channels / 中国药理学通报

Aim To study the electrophysiological mechanism of dopamine inhibiting insulin secretion hv voltage-dependent potassium ( Kv) channels.Methods Islets and (3 cells were isolated from male SD rats.D,-like receptor agonist ( SKP38393), D2-like receptor agonist (Quinpirole) and antagonist (Epiclopride) were used according to the experiment.Insulin secretion was detected by insulin radioimmunoassay.Whole-cell j J patch-clamp technique was applied to detect Kv channel currents and action potential duration of p cells.Di- BAC4(3) staining was used to observe membrane potential.Results SKF38393 did not affect insulin secretion and the Kv channel currents.Quinpirole signifi cantly inhibited insulin secretion and increased Kv channel currents.Dopamine significantly inhibited insulin secretion, increased Kv channel currents and shortened action potential duration of p cells, which could be reversed by epiclopride.In addition, dopamine de-creased membrane potential of INS-1 cells.Conclusions Dopamine inhibits insulin secretion by acting on D2-like receptors, resulting in actived Kv channels, shortened action potential duration and decreased cell membrane potential.

Comparison of two vasopressor protocols for preventing hypotension post-spinal anesthesia during cesarean section: a randomized controlled trial / 中华医学杂志(英文版)

BACKGROUND@#Norepinephrine infusion decreases hypotension after spinal anesthesia during cesarean section. This study aimed to compare the efficacy of norepinephrine infusion and ephedrine bolus against post-spinal hypotension in parturients.@*METHODS@#In this double-blinded, randomized controlled clinical trial, parturients scheduled for elective cesarean section were randomly allocated to receive norepinephrine infusion (0.05 μg·kg-1·min-1) just before spinal anesthesia continuing for 30 min or ephedrine bolus (0.15 mg/kg) just before spinal anesthesia. A rescue bolus (5 μg norepinephrine for the norepinephrine group, and 5 mg ephedrine for the ephedrine group) was administered whenever hypotension occurred. Our primary outcome was the incidence of hypotension within 30 min of spinal anesthesia administration. Secondary outcomes included maternal and neonatal outcomes 30 min after spinal block, and neonatal cerebral oxygenation 10 min after birth.@*RESULTS@#In total, 190 patients were enrolled; of these patients, 177 were included in the final analysis. Fewer patients suffered hypotension in the norepinephrine group than in the ephedrine group (29.5% vs. 44.9%, odds ratio [OR]: 0.51, 95% confidence interval [CI]: 0.28-0.95, P = 0.034). Moreover, the tachycardia frequency was lower in the norepinephrine group than in the ephedrine group (OR: 0.22, 95% CI: 0.11-0.44, P < 0.001), and patients suffered less nausea and vomiting (OR: 0.28, 95% CI: 0.11-0.70, P = 0.004). There was no difference in Apgar scores and umbilical arterial blood gas analysis between the two groups. However, neonatal cerebral regional saturations were significantly higher after birth in the norepinephrine group than in the ephedrine group (mean difference: 2.0%, 95% CI: 0.55%-3.45%, P = 0.008).@*CONCLUSION@#In patients undergoing elective cesarean section with spinal anesthesia, norepinephrine infusion compared to ephedrine bolus resulted in less hypotension and tachycardia, and exhibited potential neonatal benefits.@*TRIAL REGISTRATION@#ClinicalTrials.gov, NCT02542748; https://clinicaltrials.gov/ct2/show/record/NCT02542748.

Effect of electroacupuncture preconditioning on serum S100beta and NSE in patients undergoing craniocerebral tumor resection / 中国结合医学杂志

<p><b>OBJECTIVE</b>To investigate the effect of electroacupuncture preconditioning on the serum level of S100 calcium-binding protein beta (S100beta) and neuron-specific enolase (NSE) in patients undergoing craniocerebral tumor operation.</p><p><b>METHODS</b>A total of 32 patients, who would go through craniocerebral tumor resection under general anesthesia, were randomly assigned to two groups, 16 in each group. Patients in the electroacupuncture (EA) group received electroacupuncture on Fengfu acupoint (Du16) and Fengchi acupoint (GB20) for 30 min, 2 h before operation. The stimulus is 1-4 mA with a density wave frequency of 2/15 Hz. Patients in the control group received no pretreatment. Anesthesia was maintained with remifentanil at the dose of 4-8 mg/kg per hour, pumped intravenous drip of vecuronium at 1.0-2.0 microg/kg each hour, and discontinuous intravenous dripped with vecuronium bromide at 0.5-1 mg. The serum levels of S100beta and NSE were measured with ELISA before operation, before skin incision, after tumor removal, at the end of operation, and at 24 h after operation.</p><p><b>RESULTS</b>The serum level of S100beta and NSE did not change before skin incision. The serum level of NSE increased significantly and the level of S100beta increased insignificantly after the tumor resection. The serum levels of S100beta and NSE in the EA group and the control group were 1.16+/-0.28 microg/L vs 1.47+/- 0.33 microg/L, 24.7+/-13.3 microg/L vs 31.4+/-14.1 microg/L at the end of the operation, respectively. Twenty-four h after operation, the correspondence indices were 1.18+/-0.31 microg/L vs 1.55+/-0.26 microg/L, and 25.5+/-12.4 microg/L vs 32.4+/- 11.7 microg/L. The two indices at these two time points were significantly increased than those before operation, respectively (P<0.05). At the end of the operation and 24 h post-operation, the serum levels of S100beta and NSE in the EA group were significantly lower than those in the control group (P<0.05).</p><p><b>CONCLUSION</b>Electroacupuncture Fengchi and Fengfu for 30 min before craniocerbral tumor operation could decrease the serum level of S100beta and NSE, thus may have potential protective effect on brain damage, which needs to be further studied.</p>

Involvement of delta-and mu-opioid receptors in the delayed cerebral ischemic tolerance induced by repeated electroacupuncture preconditioning in rats / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Preconditioning with repeated electroacupuncture (EA) could mimic ischemic preconditioning to induce cerebral ischemic tolerance in rats. The present study was designed to investigate whether mu (micro)-, delta (delta)- or kappa (kappa)-opioid receptors are involved in the neuroprotection induced by repeated EA preconditioning.</p><p><b>METHODS</b>The rats were pretreated with naltrindole (NTI), nor-binaltorphimine (nor-BNI) or D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP), which is a highly selective delta-, kappa- or micro-opioid receptor antagonist respectively, before each EA preconditioning (30 minutes per day, 5 days). Twenty-four hours after the last EA treatment, the middle cerebral artery occlusion (MCAO) was induced for 120 minutes. The brain infarct volume was determined with 2, 3, 5-triphenyltetrazolium chloride staining at 24 hours after MCAO and compared with that in rats which only received EA preconditioning. In another experiment, the met-enkephalin-like immunoreactivity in rat brain was investigated by immunohistochemistry in both EA preconditioning and control rats.</p><p><b>RESULTS</b>The EA preconditioning reduced brain infarct volume compared with the control rats (P = 0.000). Administration of both NTI and CTOP attenuated the brain infarct volume reduction induced by EA preconditioning, presenting with larger infarct volume than that in the EA preconditioning rats (P < 0.001). But nor-BNI administration did not block the infarct volume reduction induced by EA preconditioning, presenting with smaller infarct volume than the control group rats (P = 0.000). The number of met-enkephalin-like immunoreactivity positive neurons in the EA preconditioning rats was more than that of the control rats (P = 0.000).</p><p><b>CONCLUSION</b>Repeated EA preconditioning stimulates the release of enkephalins, which may bind delta- and micro-opioid receptors to induce the tolerance against focal cerebral ischemia.</p>

Shenfu injection attenuates neurotoxicity of bupivacaine in cultured mouse spinal cord neurons / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Our previous in vivo study in the rat demonstrates that Shenfu injection, a clinically used extract preparation from Chinese herbs, attenuates neural and cardiac toxicity induced by intravenous infusion of bupivacaine, a local anesthetic. This study was designed to investigate whether bupivacaine could induce a toxic effect in primary cultured mouse spinal cord neuron and if so, whether the Shenfu injection had a similar neuroprotective effect in the cell model.</p><p><b>METHODS</b>The spinal cords from 11- to 14-day-old fetal mice were minced and incubated. Cytarabine was added into the medium to inhibit the proliferation of non-neuronal cells. The immunocytochemical staining of beta-tubulin was used to determine the identity of cultured cells. The cultured neurons were randomly assigned into three sets treated with various doses of bupivacaine, Shenfu and bupivacaine + Shenfu, for 48 hours respectively. Cell viability in each group was analyzed by methyl thiazoleterazolium (MTT) assay.</p><p><b>RESULTS</b>The viability of the cultured neurons treated with bupivacaine at concentrations of 0.01%, 0.02%, 0.04% and 0.08% was decreased in a dose-dependent manner. Although the Shenfu injection at concentrations ranging from 1/50 to 1/12.5 (V/V) had no significant influence on the viability of cultured neurons (P < 0.05 vs control), the injection significantly increased the cellular viability of cultured neurons pretreated with 0.03% bupivacaine (P < 0.05).</p><p><b>CONCLUSION</b>Although Shenfu injection itself has no effect on spinal neurons, it was able to reduce the bupivacaine-induced neurotoxicity in vitro.</p>