As a new laboratory test for evaluation of endogenous pain inhibition,conditioned pain modulation (CPM) deficiency means dysfunction of endogenous pain inhibitory systems and higher incidence of chronic pain.Age,psychological factors and physical activity all seem to influence the individual CPM effect.A standard CPM testing way has an important role in comparison between different researches.

After first report of local anesthetics on cardiac toxicity was published in 1979, A lot of researches of local anesthetics on the mechanism of cardiac toxicity and its treatments were reported, and some advances were reviewed in this article during recent years.

NMDA(N-Methyl-D-Aspartate)receptor is a kind of ionotropic receptors, which have been widely localized in peripheral somatic tissues and visceral pain pathways. The activation or expression changes of peripheral NMDA receptor may play an important role in pain occurrence. Peripheral administration of NMDA receptor antagonist can alleviate or prevent pain and enhance the analgesic effect of opiate. This method of administration can reduce the side effect of central action induced by the drug. It will be an important research direction of pain management.

Spinal opioids have been widely used in clinical anesthesia and analgesia. In this article, we reviews the characteristics about the clinical applications of spinal opioids, including the opioid selection, drug dosage, administration route, effects of different opioids, drug combination, associated adverse effects and so on.

Objective To evaluate the pharmacokineties of ropivacaine for single sciatic nerve block in dogs.Methods Twelve healthy adult mongrel dogs weighing 14-17 kg were randomized to receive 0.5% ropivaeaine 10 mg/kg or 20 mg/kg for single sciatic nerve block(n=6 each).ECG,BP and HR were monitored and recorded during anesthesia.Blood samples were obtained from femoral artery before ropivacaine injection (baseline)and at 10,20,30,40,60,90,120,150,180,240,360 and 720 min after ropivacaine injeetion for determination of plasma ropivaeaine concentration(by reversc-phasc high performance liquid chromatography).Arterial blood samples were also taken when adverse reactions occurred.The pharmacokinetic parameters were eMeulated with DAS 1.0 software package.Results The concentration-time curve of ropivacaine for single sciatic nenre block was fitted to two-compartment open model in both groups.The peak plasma concentration of ropivaeaine was significantly lower in 10 mg/kg group than in 20 mg/kg group.Two dogs developed convulsion in 20 mg/kg group.The plasma ropivaeaine concentration was 12.56 and 13.67 mg/L respectively during convulsion.Conclusion Pharmaeokinetic profile of ropivaeaine for single sciatic nerve block is best described by two-compartment model.Bopivaeaine 20 mg/kg for sciatic nerve block can hardly be tolerated by dogs.

Objective To investigate the safety and feasibility of anesthesia for patients with myasthenia gravis using target controlled infusion without muscle relaxant.Methods Thirty-one patients with myasthenia gravis were recruited into study.A target controlled infusion was started with targeting effect-site concentration of propofol 3 μg/mL and remifentanil 4 ng/mL.Intubation was performed when patients were unconsciousness and target concentrations of both drugs were reached.No muscle relaxant was used during anesthesia.Blood pressure,heart rate,performance of intubation and respiratory recovery including extubation and wake time were observed.Results All patients were intubated successfully in one attempt.38.7% patients had mild cough when the endotracheal tube past through the vocal cord during intubation.Blood pressure and heart rate at post-intubation increased significantly as compared with pre-intubation (P＜0.01).After cease of drugs,time of spontaneous breathing recovery was (6.5±2.9) min.Extubation and wakeup time were (9.8±3.6) and (7.4±3.1) min respectively.No adverse event was noted.Conclusion Target controlled infusion without muscle relaxant was safe and effective anesthesia for myasthenia gravis patients undergoing thymectomy.

Objective To evaluate the effect of gabapentin on Cav3.2 channels in the dorsal root ganglia ( DRG) of rats with neuropathic pain. Methods Thirty male Sprague?Dawley rats, aged 6-7 weeks, weighing 225-275 g, were divided into 3 groups ( n=10 each) using a random number table:sham operation group ( S group) , neuropathic pain group ( NP group) and gabapentin group ( G group) . In NP and G groups, neuropathic pain was induced by chronic constriction injury to the left sciatic nerve. Starting from 7th day after operation, gabapentin 100 mg∕kg in 1 ml of normal saline was injected intraper?itoneally twice a day for 7 consecutive days in group G, and the equal volume of normal saline was given twice a day for 7 consecutive days in S and NP groups. The mechanical paw withdrawal threshold ( MWT) and thermal paw withdrawal latency ( TWL) were measured on day 3 before operation and on postoperative days 3, 7 and 14. After the last measurement of pain thresholds on the postoperative day 14, 4 rats were sacrificed for determination of Cav3. 2 mRNA expression ( by real?time polymerase chain reaction) and Cav3.2 protein expression (by Western blot) in the DRG. Results Compared with S group, the MWT was significantly decreased, and TWL was significantly shortened on postoperative days 3, 7 and 14, and the expression of Cav3.2 protein and mRNA in the DRG was significantly up?regulated in group NP, and the MWT was significantly decreased, and TWL was significantly shortened on postoperative days 3 and 7 ( P<0.05), and no significant change was found in the expression of Cav3.2 protein and mRNA in the DRG in group G ( P>0.05) . Compared with NP group, the MWT was significantly increased, and TWL was signif?icantly prolonged on the postoperative day 14, and the expression of Cav3.2 protein and mRNA in the DRG was significantly down?regulated in group G ( P<0.05) . Conclusion The mechanism by which gabapentin attenuates neuropathic pain may be related to inhibition of the function of Cav3.2 channels in the DRG of rats.

5) who were conscious and had no obvious cardio-respiratory and hepato-renal dysfunction were enrolled in this study. The patients received intravenous PCA with morphine for the first 48 hours. The PCIA morphine solution contained morphine 2-6mg?ml-1 and droperidol 1-2 mg?30 ml-1 . PCIA included a bolus dose of morphine 1-3 mg with a 5 min lockout. No background infusion was given. Morphine PCIA was then combined with transdermal fentanyl. The initial dose of transdermal fentanyl was 25?g ? h-1 in the first two to three days. The dose was then gradually increased in 25 ?g?h-1 increments according to VAS scores and the amount of Ⅳ morphine needed to reduce the persistent pain until transdermal fentanyl alone could provide sufficient relief of persistent pain and Ⅳ morphine was given only for breakthrough pain. Pain intensity (VAS scores) before and after treatment, daily consumption of morphine (mg?d-1) and transdermal fentanyl (?g?h-1), vital signs and side effects were recorded.Results The 13 patients included 6 males and 7 females. Their mean (?SD) age was 54?15 yrs and body weight 53? 8 kg. There was positive correlation between the titrated dose of transdermal fentanyl (??k-1) and the initial need of Ⅳ morphine (mg?day-1). Y= 1.3606 X + 6.5088. Persistent pain intensity and breakthrough pain intensity evaluated by VAS scores were significantly reduced during the treatment ( P

0.05] between group L and other two groups.Conclusion PCEA with 0.125% levobupivacaine containing fentanyl 2 ?g?ml-1 provides adequate pain relief after cesarean section with recovery of motor function similar to that with 0.2% ropivacaine and 0.125% racemic bupivacaine.

The influences of lactic/hydrochloric acidosis on pulmonary vasoconstriction and gas exchanges were investigated in 36 dogs. The tv infusion of lactic or hydrochloric acid reducing arterial pH to 7. 00 could elicit significant changes of pulmonary hemodynamics, including the consistent increase of pulmonary arterial pressure and the decrease of arterial oxygen saturation. It is suggested that pulmonary vasocostriction is related to arterial PH but not to arterial lactic acid levels.