Objective To investigate the analgesic effect of adenosine A1 receptor agonist R( - )-N6-(2-phenylisopropyl)-adenosine (R-PIA) administered into the brainstem medial pontine reticular formation (mPRF) and the underlying mechanism. Methods Sixty male SD rats aged 8-10 weeks weighing 250-300 g were used in this study. The animals were anesthetized with intraperitoneal 10% chloral hydrate 300 mg?kg-1 .A 24-gauge stainless steel cannula was inserted into mPRF on one side using a stereotaxic apparatus. One week after operation the animals were randomly divided into 12 groups ( n=5 each) : groupⅠcontrol; groupⅡR-PIA 0.5?g; groupⅢR-PIA 1.0?g; groupⅣR-PIA 2.0?g; groupⅤtheophylline (an adenosine receptor antagonist) 5.0?g; groupⅥ8-cyclopentyl-1 ,3-dipropylxanthine (DPCPX, an adenosine A, receptor antagonist) 1.0?g; groupⅦglibenclamide (an ATP-sensitive K+ channel blocker) 5.0?g; groupⅧ4-aminopyridine (4-AP, a voltage dependent K+-channel blocker) 5.0?g; groupⅨtheophylline 5.0?g + R-PIA 2.0?g; groupⅩDPCPX 1.0?g + R-PIA 2.0?g; groupⅪglibenclamide 5.0?g + R-PIA 2.0?g and groupⅫ4-AP 5.0?g + R-PIA 2.0?g. All the drugs were injected into mPRF in 0.3?l of normal saline. In groupⅨ-ⅫR-PIA 2.0?g was administered 15 min after pretreatment with theophylline, DPCPX, glibenclamide or 4-AP. Analgesia was determined using the tailflick latency (TFL) (the time between the onset of the radiant heat stimulus and voluntary tail withdrawal) at 5, 15, 30, 45, 60 and 90 min after R-PIA injection into mPRF. The pain threshold was expressed as percentage of the maximal possible effect ( MPE) : MPE = (TFL after drug - baseline TFL)/( 10.0 -baseline TFL)?100% .Results R-PIA 0.5-2.0?g injected into mPRF produced significant analgesia in a dose-dependent manner. Pretreatment with theophylline or DPCPX completely reversed the analgesic effect of R-PIA while pretreatment with glibenclamide or 4-AP only partially reversed the analgesic effect of R-PIA.Conclusion R-PIA administered into mPRF produces analgesia through activation of both ATP-sensitive and voltage-dependent K+ -channel in mPRF.

Objective To investigate the effect of propofol on the activation of NF-?B and the expression of Bcl-2 and Caspase-3 gene in cerebral cortex after transient focal cerebral ischemia-reperfusion (I/R) and the possible mechanism. Methods Ninety healthy male Wistar rats aged 3-4 months weighing 250-300g were randomly divided into 3 groups (n=30 each) : group Ⅰ sham operation; group Ⅱ I/R and group Ⅲ propofol + I/R. The animals were anesthetized with intraperitoneal chloral hydrate 300 mg?kg-1. Left common, internal and external carotid arteries (CCA, ICA, ECA) were exposed. Middle cerebral artery occlusion (MCAO) was produced by inserting a nylon thread, 0.26-0.28 mm in diameter and 4.0 cm in length into ICA and advancing it cranially until resistance was felt. After 2 h MCAO the nylon thread was withdrawn to allow reperfusion. In propofol group propofol 100 mg?kg-1 was given IP 10 min before MCAO. The animals were decapitated at 2, 3, 6, 12, 24 and 72 h of reperfusion (n=5 at each time point in each group) . Their brains were immediately removed for determination of translocation of NF-?B in the neurons (by immuno-histochemistry) and expression of NF-?B in cerebral cortex (by Western blotting). The expression of Bcl-2 mRNA and Caspase-3 mRNA in cerebral cortex was determined by in situ hybridization. Neurological deficit was scored and microscopic examination of ischemic cerebral cortex was performed at 24 h of reperfusion. Results In I/R group (Ⅱ) NF-?B was significantly translocated from cytoplasm into the nucleus of the neurons in the ischemic cerebral cortex during 2-24 h of reperfusion while in non-ischemic cortex NF-?B was confined to the cytoplasm. The expression of NF-?B, Bcl-2 mRNA and Caspase-3 mRNA was significantly higher in ischemic cortex than in non-ischemic cortex. Neurologic deficit scores were higher in I/R group than in sham-operation group. Microscopic examination showed congestion and edema of ischemic cerebral cortex and degeneration and necrosis of the neurons in I/R group. In group Ⅲ propofol pretreatment significantly inhibited the translocation of NF-?B, decreased expression of NF-?B and Caspase-3 mRNA and increased Bcl-2 mRNA expression as compared with I/R group (Ⅱ) . Neurologic dificit and histologic damage induced by I/R were significantly ameliorated by propofol pretreatment. Conclusion Propofol pretreatment can inhibit apoptosis of neurons induced by I/R by inhibiting the activation of NF-B, up-regulating Bcl-2 gene and down-regulating Caspase-3 gene.

Objective To investigate the effect of ketamine on the synaptic long-term potentiation(LTP) in the CA1 area of rat hippocampal slices,and to elucidate the mechanisms underlying the effect of ketamine on memory.Methods Hippocampal slices(400 ?m thick) were obtained from the brains of male Sprague-Dawley rats(2 months old) weighing 200-250 g that were decapitated.The slices were incubated in artificial cerebrospinal fluid(ACSF) at room temperature for at least 120 min before use.Forty-nine slices were randomly divided into 7 groups(n=7):control group,ketamine 1,5,10,30,50 and 100 ?mol?L-1 groups.All the slices in each group were perfused with ACSF,ketamine 1,5,10,30,50 or 100 ?mol?L-1,respectively.The slices in each group were performed to record evoked population spikes(PS) using extracellular microelectrode recording technique.Another forty-nine slices were randomly divided into 7 groups(n=7):LTP group,ketamine-LTP 1,5,10,30,50 and 100 ?mol?L-1 groups.All the slices in each group were perfused with ACSF,ketamine 1,5,10,30,50 or 100 ?mol?L-1,respectively.PSs were recorded for at least 30 min before LTP in each group.For LTP induction,high-frequency stimulation(HFS) conditioning pulses(100 Hz?s-1) were applied to the Schaffer collateral-commissural pathway of hippocampus using a bipolar stimulating electrode.The changes in PS amplitude after HFS were analyzed in each group.Results The PS amplitude of the rat hippocampal slices in ketamine 1,5,and 10 ?mol?L-1 groups had no significant difference compared with control group.The PS amplitude in ketamine 30,50 and 100 ?mol?L-1 groups decreased compared with control group(P

Objective To evaluate the effects of patient controlled analgesia(PCEA)on the perioperative changes of circulatory and pulmonary function of elderly with hypertensions after abdominal surgery.Methods Twenty-eight patients of ASAⅡ-Ⅲ aged more than 60 years undergoing uratomy were randomly divided into two groups:control group and PCEA group.Preoperative and postoperative circulatory and pulmonary functions were measured with noninvasion circulatory monitor and pocket lung function meter respectively.Results In control group,the systolic pressure,diastolic pressure,and heart rate increased by 19%,17% and 19%,respectively,as compared with preoperation.The percentage of forced vital capacity(FVC%),percentage of forced expiratory volume in first second to forced vital capacity(FEV1%) and percentage of maximal ventilatory volume(MVV%) of postoperation in control group were significantly decreased compared with preoperation(P

0.05),but it was significantly lower than that in LTP group (P

Objective To discuss the effects of sevoflurane on perioperative hemodynamics and serum cardiac troponin I(cTnI) in patients undergoing abdominal surgery,and offer the reference for selecting anesthetic in clinic.Methods Forty patients with ASA Ⅱ—Ⅲ,undergoing radical gastrectomy were randomly allocated into sevoflurane group(group S) and propofol group(group P),with each 20 patients.Systemic blood pressure(SBP),diastolic blood pressure(DBP),heart reat(HR) and saturation of oxygen(SPO2) were monitored as routine.The concerntration of cTnI was examined at pre-anesthesia(T1),post-induction(T2),beginning of operation(T3),end of operation(T4),the first day post-operation(T5) and the third day post-operation(T6) with radioimmunoassay.Results SBP,DBP and HR in group P at post-induction were significantly lower than those in group S(P

0.05).Significant differences were observed in analgesia grade between two groups.Visual analogue scores(VAS) in different postoperative time points(4,8,12,24 and 48h) were lower in experiment group than those in control group(P0.05).Conclusion Flurbiprofen axeti1 has preemptive analgesia effects with the chosen dosage regimen in patients undergoing thoracotomy and doesn't increase side effects.But the preemptive analgesia can't improve postoperative respiratory function.

ObjectiveTo observe the changes of HR,MAP,BIS and Narcotrend induced by different doses of propofol in elderly patients. MethodsOne hundred elder patients(60 ～ 85 years old), AS A class Ⅰ or Ⅱ, scheduled for selective surgeries,were divided equally into 5 different doses of propofol( constant intravenous injection for 1min) groups of 0.5mg/kg( Ⅰ ) ,0. 75mg/kg( Ⅱ ) ,1.0mg/kg(Ⅲ) ,1.25mg/kg( Ⅳ)and 1.5mg/kg(Ⅴ). HR,MAP,BIS and Narcotrend were monitored before propofol injection and at 1 and 5 min after propofol injection. ResultsHR of 5 group s as similar. At 1 min after pmpofol injection, MAP decreased remarkably compared with at before in all 5 groups( t =2. 17,2.84,2.49,5.63,7.10, all p ＜ 0.05 ), which in group Ⅳ and Ⅴ decreased significantly compared with at in group Ⅰ, Ⅱ and Ⅲ(t =4.67,2.77,2.45,5.49,4.57,2. 18,all P＜0.05).At 1 min after propofol injection,BIS and NI values decreased compared with at before in all 5 groups(t =7.74,11.74,28.18,30.34,45.28, 6. 65,10.52,17.27,26.28,30. 14,allP ＜0.05) ,which in groupⅢ, Ⅳ and Ⅴ were significantly lower than those in group Ⅰ and Ⅱ (t =12.59,11.08,16.72,15.12,17.67,15.64,allP＜0.05).Dose of propofol was negatively correlated with BIS and NI value ( r =-0. 898/0. 930, P ＜ 0.01 ). ConclusionPropofol 1.0mg/kg constant injection should meet the sedation and hypnosis demand of general anesthesia in elderly patients and could not inhibit circulatory system; Bispectral Index and Narcotrend could accuratly monitor depth of anesthesia in elderly patients.

Objective To evaluate the effect of hypothermia on somatosensory evoked potentials (SSEPs). Methods Thirteen ASA Ⅱ or Ⅲ patients aged 23-51 yr weighing 45-82 kg scheduled for cardiac surgery were enrolled in this study. Bilateral median nerve SSEPs (N9, N13, N20) were recorded after induction.The MAP, peak latency and amplitude of N9, N13 and N20 were recorded when the target temperature (36, 35,34, 33 ℃ ) was reached during the cooling and rewarming periods. The neurological dysfunction was recorded after operation. Results The peak latency was prolonged and MAP was decreased with the decrease in the body temperature during the cooling period, the peak latency was shortened with the increase in the body temperature during the rewarming period ( P ＜ 0.05), but no significant change in the amplitudes was found ( P ＞ 0.05). The regression equation of the interaction between the peak latency and body temperature was YN9= -0.558X + 28.994(r=-0.673), YN13 =-1.121X+53.242 (r= -0.702) , YN20 = -1.458X+72.036(r= -0.702) during the cooling period (P ＜ 0.05), and YN9 = - 0.505X + 27.313 ( r = - 0.634), YN13 = - 0.905X + 46.249(r= -0.619), YN20 = - 1.142X + 61.668 (r= -0.600) during the rewarming period (P ＜0.05). No neurological dysfunction was found in all the patients. Conclusion Hypothermia can prolong the peak latency of SSEP and does not alter the SSEP amplitude.

Objective To investigate the variation in the position of conus medullaris in Chinese adult population in order to avoid hitting conus during spinal puncture. Methods Eight hundred patients suffering from back pain, aged 18-91 yr, were enrolled in this study. The position of conus medullaris was determined using Siemens 1.5 T magnetic resonance imaging system. According to the method described by Reimann, the vertebral body was used as mark of reference to the level of the end of conus. Results There were 190 patients in whom the position of the end of conus medullaris was lower than L1,2 . The incidence of the position of the end of conus medullaris lower than L1,2 was higher in patients 30-60 or older than in those under 30, and in those over the age of 60 than in those 30-60 (P ＜ 0.05). Conclusion Spinal puncture should be performed cautiously at L2,3. CT or MRI is recommended before operation for the patients to locate the position of conus medullaris and avoid injury to the spinal cord.