Dexmedetomidine Attenuates Neuropathic Pain by Inhibiting P2X7R Expression and ERK Phosphorylation in Rats

α2-Adrenoceptor agonists attenuate hypersensitivity under neuropathic conditions. However, the mechanisms underlying this attenuation remain largely unknown. In the present study, we explored the potential roles of purinergic receptor 7 (P2X7R)/extracellular signal-regulated kinase (ERK) signaling in the anti-nociceptive effect of dexmedetomidine in a rat model of neuropathic pain induced by chronic constriction injury (CCI) of the sciatic nerve. An animal model of CCI was adopted to mimic the clinical neuropathic pain state. Behavioral hypersensitivity to mechanical and thermal stimuli was determined by von Frey filament and Hargreaves' tests, and the spinal P2X7R expression level and ERK phosphorylation were analyzed using western blot analysis and immunohistochemistry. In parallel with the development of mechanical and thermal hyperalgesia, a significant increase in P2X7R expression was noted in the ipsilateral spinal cord on day 7 after CCI. Intrathecal administration of dexmedetomidine (2.5 µg) for 3 days not only attenuated neuropathic pain but also inhibited the CCI-induced P2X7R upregulation and ERK phosphorylation. Intrathecal dexmedetomidine administration did not produce obvious effects on locomotor function. The present study demonstrated that dexmedetomidine attenuates the neuropathic pain induced by CCI of the sciatic nerve in rats by inhibiting spinal P2X7R expression and ERK phosphorylation, indicating the potential therapeutic implications of dexmedetomidine administration for the treatment of neuropathic pain.

Influence of Guiqiyiyuan Ointment on the expression of caspase-3 and caspase-9 in rat lung tissues injured by heavy ion radiation-induced bystander effect / 解放军医学杂志

Objective To explore the influence of Guiqiyiyuan Ointment on the expressions of caspase-3 and caspase-9 in the lung and kidney of the rats damaged by heavy ion (12C6+) radiation-induced bystander effect.Methods The Wistar male rats were equally and randomly divided into seven groups,normal control group (NCG),radiation alone group (RAG) and Chinese medicine group (CMG),with the latter two groups being redivided into 6,12 and 24h groups according to the executing time.The Chinese medicine groups were given Guiqiyiyuan Ointment by gavage for two weeks in advance.The normal control group and the radiation alone groups were given the equal normal saline.Afterwards,the right lung of the rats in the radiation alone groups and Chinese medicine groups were radiated by 2Gy 12C6+ ion once.The rats in normal control group were not radiated.All groups of rats were executed 6,12,and 24h after radiation.The protein and mRNA expressions of caspase-3 and caspase-9 in the right lung,left lung and left kidney were examined with immunohistochemistry and Q-PCR.Results Compared with the normal control group,the mRNA expressions of caspase-3 and caspase-9 in the right lung,left lung and left kidney in the radiation alone groups obviously increased 6 and 24h after radiation.While the protein expressions of caspase-3 and caspase-9 in the radiation alone group obviously increased only 24h after radiation (P＜0.01).Compared with the radiation alone groups,the expressions of protein and mRNA ofcaspase-3 and caspase-9 were obviously down-regulated in the Chinese medicine groups (P＜0.01).Conclusion By controlling the up-regulation of the expression ofcaspase-3 and caspase-9,Guiqiyiyuan Ointment can prevent the lung and kidney cell apoptosis and alleviate the damage caused by heavy ion radiation-induced bystander effect in vivo.

Worry about ill consequences in cancer patients and its relationship with depression / 重庆医学

Objective To understand the worry situation about ill consequences in cancer patients and its relationship with depression.Methods The inpatients with cancer were extracted from 4 general hospitals of Wuhan and Beijing city by the cluster sampling.The self-designed questionnaires were adopted to survey the worry situation about ill consequences in cancer patients.The self-rating depression scale (SDS) was used to assess the patients' depression status.Results A total of 485 cancer patients were surveyed,including 204 males (42.1 ％),281 females(57.9 ％),and the mean age was (56.59 ± 11.19)years old.More than half of the patients usually or always worried about medical expenses.Worries about not taking care of their children,losing their lives,physical disability,leaving sequela and losing life ability also happened a lot.Patients worried more about losing their life,the possibility appearing depression was greater (P＜0.05).The younger the patients were,the greater the depression possibility was;the company staffs had lower risk of depression compared with those whose occupation was others (P＜0.05).Conclusion Cancer patients have different degrees of worries about ill consequences such as medical expenses,not taking care of their children and losing their lives and their worries about losing their lives could affect their depression status.

Worry about ill consequences in cancer patients and its relationship with depression / 重庆医学

Objective To understand the worry situation about ill consequences in cancer patients and its relationship with depression.Methods The inpatients with cancer were extracted from 4 general hospitals of Wuhan and Beijing city by the cluster sampling.The self-designed questionnaires were adopted to survey the worry situation about ill consequences in cancer patients.The self-rating depression scale (SDS) was used to assess the patients' depression status.Results A total of 485 cancer patients were surveyed,including 204 males (42.1 ％),281 females(57.9 ％),and the mean age was (56.59 ± 11.19)years old.More than half of the patients usually or always worried about medical expenses.Worries about not taking care of their children,losing their lives,physical disability,leaving sequela and losing life ability also happened a lot.Patients worried more about losing their life,the possibility appearing depression was greater (P＜0.05).The younger the patients were,the greater the depression possibility was;the company staffs had lower risk of depression compared with those whose occupation was others (P＜0.05).Conclusion Cancer patients have different degrees of worries about ill consequences such as medical expenses,not taking care of their children and losing their lives and their worries about losing their lives could affect their depression status.

Effect of Volatile Oil of Radix Angelicae Sinensis on experimental asthma in rats / 中国应用生理学杂志

<p><b>OBJECTIVE</b>To study the effects of Volatile Oil of Radix Angelicae Sinensis (VOA) on experimental asthma in rat model based on abnormal immune functions of Treg cells.</p><p><b>METHODS</b>After grouping, the asthmatic rats were developed through injecting OVA and AI(OH)3 for sensitization and then administering OVA aerosol for challenge, and the respiratory functions, asthmatic behaviors, IL-10 levels in bronchoalveolar lavage fluid (BALF) (ELISA) and Foxp3 expression (immunohistochemistry) in lung of asthmatic rats were observed.</p><p><b>RESULTS</b>VOA at the doses of 40-160 mg/kg could improve the respiratory functions and the asthmatic behaviors, and upgrade IL-10 levels in BALF and Foxp3 expression in lung of asthmatic rats.</p><p><b>CONCLUSION</b>VOA has some effects of anti-asthma and one of the mechanisms is to improving the lower immune functions of Treg cells.</p>

Combined use of transmyocardial laser revascularization and endothelial progenitor cells enhances neovascularization and regional contractility in a canine model of ischemic hearts / 华中科技大学学报（医学）（英德文版）

The purpose of this study was to determine the combined effect of transmyocardial laser revascularization (TMLR) and the implantation of endothelial progenitor cells (EPCs) on cardiac function of ischemic hearts in canines. The left anterior descending artery (LAD) was occluded to establish the canine model of acute myocardial infarct (AMI). Four weeks later, the animals were randomly divided into four groups: TMLR group, in which transmyocardial laser-induced channels were established at the ischemic region; EPCs+TMLR group, in which EPCs were locally transplanted into laser-induced channels at the ischemic region; EPCs group, in which the EPCs were injected into the ischemic region; control group, in which the AMI animals received neither TMLR nor EPCs. The peripheral blood (50 mL) was sampled in all groups. Mononuclear cells from the peripheral blood were separated and cultured to obtain spindle-shaped attaching (AT) cells in vitro. AT cells were labeled with 1, 1'-dioctadecyl-1 to 3,3, 3',3'-tetramethyl-indocarbocyanine perchlorate (DiI) before injecting into the laser-induced channels or ischemic region. Four weeks after the first operation, TMLR was performed in the TMLR group and EPCs+TMLR group, and at the same time, the EPCs originating from the AT cells were mixed with calcium alginate (CA). Then the EPCs-CA composites were implanted into myocardial channels induced by laser in the EPCs+TMLR group, and into the myocardial infarct area in the EPCs group. All dogs underwent echocardiography at second month after LAD occlusion. Finally the samples of myocardium around the LAD were subjected to histochemical and immunohistologic examinations. The results showed there was no significant difference in the diameter of left atrium and ventricle before treatment among all groups (P>0.05). Eight weeks after modeling, the regional contractility in the LAD territory in the EPCs+TMLR group was increased as compared with control group and TMLR group, but there was no significant difference between control group and TMLR group. Neoangiogenesis was observed in the EPCs+TMLR group, and the fibrosis was seen in the TMLR group. There was no significant difference in neoangiogenesis around the channels induced by laser among EPCs+TMLR, EPCs and TMLR groups. It was concluded that TMLR combined with EPCs could improve the regional and global cardiac function in AMI, and augment neovascularizaiton in channels of ischemic myocardium induced by laser.

Effects of heme oxygenase-1 protein transduction on intestinal injury in septic rats / 中华麻醉学杂志

Objective To investigate the effects of heme oxygenase-1 (HO-1) protein transduction mediated by cell penetrating peptide PEP-1 on intestinal injury in a rat model of sepsis induced by cecal ligation and puncture (CLP).Methods Twenty-four healthy male Sprague-Dawley rats,aged 7-9 weeks,weighing 210-260 g,were randomly divided into 4 groups (n =6 each) using a random number table:sham operation group (group S),group CLP,low-dose fusion protein PEP-1-HO-1 + CLP group (group P1) and high-dose fusion protein PEP-1-HO-1 + CLP group (group P2).Fusion protein PEP-1-HO-1 0.3 mg was administrated via the left iliac vein at 1 h before CLP and 5 h after CLP in group P1.Fusion protein PEP-1-HO-1 0.6 mg was administrated via the left iliac vein at 1 h before CLP and 5 h after CLP in group P2.The equal volume of normal saline was given instead of PEP-1-HO-1 in the other groups.The animals underwent laparotomy,but the caecum was not ligated or punctured in group S.Blood samples were collected at 12 h after CLP from the right common carotid artery for measurement of serum TNF-α and IL-6 levels.The rats were then sacrificed and intestines were removed for microscopic examination and for determination of malondialdehyde (MDA) content and superoxide dismutase (SOD) activity in intestinal tissues.Results Compared with group S,the serum TNF-α and IL-6 levels,and MDA content in intestinal tissues were significantly increased,while SOD activity in intestinal tissues was decreased in CLP,P1 and P2 groups.Compared with group CLP,the serum TNF-α and IL-6 levels,and MDA content in intestinal were significantly decreased,while SOD activity in intestinal tissues was increased in P1 and P2 groups.Compared with group P1,the serum TNF-α and IL-6 levels,and MDA content in intestinal tissues were significantly decreased,while SOD activity in intestinal tissues was increased in group P2.The pathological changes of intestines were significantly mitigated in P1 and P2 groups as compared with group CLP.Conclusion HO-1 protein transduction attenuates intestinal injury induced by sepsis in rats,and the mechanism is related to inhibition of systemic inflammatory responses and lipid peroxidation in intestinal tissues.

Combined use of transmyocardial laser revascularization and endothelial progenitor cells enhances neovascularization and regional contractility in a canine model of ischemic hearts / 华中科技大学学报（医学）（英德文版）

The purpose of this study was to determine the combined effect of transmyocardial laser revascularization (TMLR) and the implantation of endothelial progenitor cells (EPCs) on cardiac function of ischemic hearts in canines. The left anterior descending artery (LAD) was occluded to establish the canine model of acute myocardial infarct (AMI). Four weeks later, the animals were randomly divided into four groups: TMLR group, in which transmyocardial laser-induced channels were established at the ischemic region; EPCs+TMLR group, in which EPCs were locally transplanted into laser-induced channels at the ischemic region; EPCs group, in which the EPCs were injected into the ischemic region; control group, in which the AMI animals received neither TMLR nor EPCs. The peripheral blood (50 mL) was sampled in all groups. Mononuclear cells from the peripheral blood were separated and cultured to obtain spindle-shaped attaching (AT) cells in vitro. AT cells were labeled with 1, 1'-dioctadecyl-1 to 3,3, 3',3'-tetramethyl-indocarbocyanine perchlorate (DiI) before injecting into the laser-induced channels or ischemic region. Four weeks after the first operation, TMLR was performed in the TMLR group and EPCs+TMLR group, and at the same time, the EPCs originating from the AT cells were mixed with calcium alginate (CA). Then the EPCs-CA composites were implanted into myocardial channels induced by laser in the EPCs+TMLR group, and into the myocardial infarct area in the EPCs group. All dogs underwent echocardiography at second month after LAD occlusion. Finally the samples of myocardium around the LAD were subjected to histochemical and immunohistologic examinations. The results showed there was no significant difference in the diameter of left atrium and ventricle before treatment among all groups (P>0.05). Eight weeks after modeling, the regional contractility in the LAD territory in the EPCs+TMLR group was increased as compared with control group and TMLR group, but there was no significant difference between control group and TMLR group. Neoangiogenesis was observed in the EPCs+TMLR group, and the fibrosis was seen in the TMLR group. There was no significant difference in neoangiogenesis around the channels induced by laser among EPCs+TMLR, EPCs and TMLR groups. It was concluded that TMLR combined with EPCs could improve the regional and global cardiac function in AMI, and augment neovascularizaiton in channels of ischemic myocardium induced by laser.

A cross-sectional study on diabetes among the migrating population in Inner Mongolia / 中华流行病学杂志

Objective To investigate the prevalence rates of diabetes and pre-diabetes among migrating population in Inner Mongolia.Methods Using stratified cluster sampling on different industries.Each industry would have the same sample size.Questionnaire survey was performed together with anthropometric data gathered and laboratory tests completed.Results The prevalence rates of diabetes and impaired glucose regulation (IGR) among the migrating population in Inner Mongolia were 12.5％ and 12.8％ with the age-standardized rate as 9.9％ and 9.9％.The prevalence of diabetes increased significantly along with the increase of age among both males and females (x2=11.162,P=0.001),but was significantly higher in males.The prevalence of IGR in females was significantly higher than in males.The prevalence of diabetes among the construction industry workers was 19.2％,which was the highest among all the industries.The prevalence of diabetes was higher in the inter-province pre-migrating group,while the prevalence of IGR was increasing along with the duration of migration in the intra-province migration group with the trend as x2=9.989,P=0.002.Conclusion The prevalence of diabetes among the migrating population in Inner Mongolia seemed to be high,close to the level of urban residents.The prevalence rates of diabetes in the population of middle-aged and aged population as well as workers at the construction industry were higher than that in the other populations.The prevalence of diabetes and IGR among the migration population were related to the area where the migration population the in-coming areas Inter-provincial migration had a higher contribution to the prevalence of diabetes.

Efficacy of postoperative antiviral combined transcatheter arterial chemoembolization therapy in prevention of hepatitis B-related hepatocellular carcinoma recurrence / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Recurrence of hepatitis B-related hepatocellular carcinoma (HCC) after curative resection is the leading factor influencing the prognosis of the disease. Therefore, further improvement of long-term survival may depend on the prevention and treatment of the recurrent tumor. The aim of this research was to investigate the role of antiviral therapy and postoperative transcatheter arterial chemoembolization (TACE) in the prevention and treatment of hepatitis B-related HCC recurrence.</p><p><b>METHODS</b>One hundred and twenty patients who underwent curative resection of hepatitis B-related HCC between January 2005 and June 2008 at our hospital were enrolled. Patients were divided into four groups according to the post-operative adjuvant therapy they received, i.e., control, antiviral therapy group, TACE group, and combined group. The disease-free survival (DFS) and the 12-, 24-, 36-month cumulative recurrence rates were studied.</p><p><b>RESULTS</b>There was no significant difference between isolated postoperative antiviral therapy group and control in terms of disease-free survival (P = 0.283), while it was significantly higher in the TACE group compared to control (P = 0.019). In all patients, however, viral prophylactic therapy combined with/without TACE brought a favorable result compared to those only with/without TACE (P < 0.001). Similarly, no matter combined with or without antiviral treatment, postoperative TACE prolonged DFS (P = 0.015). Naturally, a combination of viral prophylactic therapy on the baseline TACE significantly benefited patients' postoperative DFS (P = 0.047) and vice verse (P = 0.002). The 24-month cumulative recurrence rates of combined group were significantly lower than that of isolated control group and antiviral therapy (P < 0.001 and P = 0.011 respectively). However, 36-month recurrence rate was significantly different in the control group compared to the TACE group and combined group (P = 0.040 and 0.002 respectively); same as the antiviral group compared to the combined group (P = 0.034).</p><p><b>CONCLUSIONS</b>Post-operative TACE prevents early recurrence while antiviral therapy prevents late recurrence of HCC. Combination of antiviral therapy and TACE are suggested for prevention in HCC patients with high risk of recurrence.</p>

Effects of heme oxygenase-1 transduced by cell penetrating peptide PEP-1 on renal ischemia/reperfusion injury in rats / 中华麻醉学杂志

Objective To investigate the effects of heme oxygenase-1 (HO-1) transduced by cell penetrating peptide PEP-1 on renal ischemia/reperfusion (I/R) injury in rats.Methods Eighteen male Sprague-Dawley rats,aged 7-9 weeks,weighing 210-260 g,were randomly divided into 3 groups (n =6 each):sham operation group (group S),renal I/R injury group (group I/R) and fusion protein PEP-1/HO-I + I/R group (group HO).I/R injury was produced by occluding bilateral renal arteries for 45 min followed by reperfusion for 6 h.The fusion protein PEP-1/HO-1 was injected via the left iliac vein 30 min prior to ischemia in group HO.Bilateral renal arteries were only exposed but not occluded in group C.Blood samples were collected from the right common carotid artery at 6 h of reperfusion for determination of serum blood urea nitrogen (BUN) and creatinine (Cr) concentrations.The malondialdehyde (MDA) content,superoxide dismutase (SOD) activity and HO-1 expression in renal tissues were measured.Results Compared with group S,the levels of MDA,serum BUN and Cr were significantly increased,the SOD activity was decreased,and HO-1 expression was up-regulated in groups I/R and HO (P ＜0.05).Compared with group I/R,the levels of MDA,serum BUN and Cr were significantly decreased,the SOD activity was increased,and HO-1 expression was up-regulated in group HO (P ＜ 0.05).Conclusion HO-1 protein can be successfully transduced into renal tissues by PEP-1 and transduced HO-1 protein reduces renal I/R injury by inhibiting lipid peroxidation response.

Histone deacetylase inhibitor promotes differentiation of embryonic stem cells into neural cells in adherent monoculture / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Embryonic stem (ES) cells poss unlimited self-renewal capacity and the ability to differentiate into cell of all three germ layers in vitro. Induced differentiation of ES cells to neural lineage cells has great potential in basic study of neurogenesis and regeneration therapy of neurodegenerative diseases. Histone deacetylase (HDAC) inhibitors enhance histone acetylation so that globularly activate gene expression and may initiate multilineage differentiation. In this study, we aimed to develop a method to induce the differentiation of ES cells to neural cells combining HDAC inhibition and neural cell selection.</p><p><b>METHODS</b>In this study, we used HDAC inhibitor sodium butyrate (NaB) to induce the differentiation of mouse embryonic stem cells to neural cells through monolayer culture. After differentiation initiation by histone deacetylase inhibitor sodium butyrate, neural cells were induced and selected with a serum free culture system.</p><p><b>RESULTS</b>Homogeneous neurons without glial cells demonstrated by molecular marker expression were differentiated with the method. The resultant neurons were excitable.</p><p><b>CONCLUSION</b>The method combined differentiation induction effect of HDAC inhibitors and selective culture system to derive neural cells from ES cells, and implied the involvement of epigenetic regulation in neural differentiation.</p>

PET/CT-based classification of delayed radiation encephalopathy following radiotherapy for nasopharyngeal carcinoma / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate positron-emission tomography-computed tomography (PET/CT) findings of radiation encephalopathy (RE) following radiotherapy for nasopharyngeal carcinoma (NPC), observe the metabolic changes of the compromised brain tissues, and postulate the clinical classification of RE to provide reference for its diagnosis.</p><p><b>METHODS</b>This study included 53 pathologically confirmed NPC patients who received previous radical radiotherapy, and the diagnosis of RE was established according to the clinical manifestations and CT/PET findings. All the patients underwent PET/CT whole-body and head scans, and the image data were evaluated along with the clinical data of the patients.</p><p><b>RESULTS</b>RE most frequently involved the lateral or bilateral inferior temporal lobes. PET identified hypometabolic changes in the bilateral temporal lobes of 35 patients (70 lobes) and in the lateral temporal lobe of 18 patients (18 lobes). According to the PET/CT findings, the lesions were classified into 3 types, namely the oedema type (56 temporal lobes), liquefactive necrosis type (10 temporal lobes), and atrophic calcification type (22 temporal lobes). One patient with oedema type lesion received neurotrophic treatment and recovered completely with normal brain tissue density and metabolism, but the oedema type lesions in 2 patients progressed into to atrophic calcification type; the liquefactive necrotic lesions in another 2 patients also progressed into atrophic calcification type.</p><p><b>CONCLUSION</b>RE patients exhibit significant hypometabolic changes in the inferior temporal lobe on PET. According to the findings by PET/CT, RE can be classified into the oedema type, liquefactive necrosis type, and atrophic calcification type, and lesions of the former two types may progress into the third type.</p>

Analysis on body impairment assessment upon 447 thoracolumbar, spinal injury cases in traffic accidents / 法医学杂志

OBJECTIVE@#To discuss the relation between degree of body impairment and that of thoracolumbar spinal injuries resulting from road traffic accidents, and sum up the experiences in body impairment assessment and its regularity.@*METHODS@#For comprehensive body impairment assessment, 477 cases of thoracolumbar spinal injuries in road accidents have been sorted out, reassessed and rediagnosed. In addition, analyses have been undertaken about their treatment, the assessment of the degree of their thoracolumbar dysfunction,nerve dysfunction and the relations between injuries and sequelaes.@*RESULTS@#The analyses show that the degree of thoracolumbar dysfunction and that of the post-injury nerve dysfunction don't necessarily depend on the quantity and degree of spinal injuries. However, the position suffering from the thoracolumbar spinal injuries has an immense impact on the thoracolumbar dysfunction, and the nerve impairment result mainly from the T1-1L spinal injuries. The research also shows that there has been a high misdiagnosis rate in hospital about the spinal injuries.@*CONCLUSION@#In body impairment assessment, the cause and effect relations between the injury and degree of injury extent should be analyzed, the injury extent should be employed as principal evidence, and the degree of spinal dysfunction should be taken into greater consideration.

Designing and implementation of a PACS / 中国医疗器械杂志

PACS (Picture Archiving and Communication System) is successfully applied in Huzhou Central Hospital, and is well integrated with its HIS system by WEBSERVICE middleware. The system supports DICOM 3.0 Standard, and DICOM gateways are installed for modalities that do not support DICOM so as to have implemented the digitalization of all the image departments in the hospital.

Effects of amiloride on potassium and calcium currents in guinea pig ventricular myocytes / 药学学报

<p><b>AIM</b>To elucidate the possible mechanisms underlying antiarrhythmia of the non-selective Na+/H+ exchanger inhibitor--amiloride.</p><p><b>METHODS</b>Single ventricular cells were isolated using a double-enzyme method. Effects of amiloride on voltage-dependent potassium and calcium currents in isolated guinea pig ventricular myocyte were recorded by using whole-cell patch clamp techniques.</p><p><b>RESULTS</b>Exposure to amiloride (10 -100 micromol x L(-1)), the L-type and T-type calcium currents were depressed. Amiloride resulted in a concentration-dependent inhibition of peak (Ca,L), But amiloride did not change the shape of their I - V curves. It only decreased the amplitudes of the currents of the two types. When myocytes were incubated with 100 micromol x L(-1) amiloride, I(Kr) was slightly depressed and I(Ks) did not change. Amiloride (1 - 100 micromol x L(-10) depressed I(K1) in a concentration-dependent manner.</p><p><b>CONCLUSION</b>Amiloride depressed potassium and calcium currents, which may give support to its uses in some diseases of the cardiovascular system.</p>

Effects of Rbl on action potentials and force of contraction in guinea pig ventricular papillary muscles / 中国中药杂志

<p><b>OBJECTIVE</b>To evaluate the effects of Rbl on action potentials and force of contraction in guinea pig ventricular papillary muscles.</p><p><b>METHOD</b>The ventricular papillary muscles of guinea pig were isolated regularly and immersed with Tyrode, s solution. The effects of Rbl (purified saponins of panaxnotoginseng) on the action potentials (AP), the slow action potentials and the force of contraction (FC) of the muscles were studied. The AP and FC were measured synchronously.</p><p><b>RESULT</b>Rbl shortened the duration of AP, including APD2O and APD90, and reduced the FC(n = 5, P < 0.01), but didn't affect the rest potential (RP), the amplitude of action potential (APA), overshot (OS) and maximal upstrok velocity (Vmax). Rbl also decreased the APA of slow action potential, but quinidine had no such effects.</p><p><b>CONCLUSION</b>Rbl may be a channel blocker.</p>

Effect of ouabain on the aortic rings of guinea pig and its interactions with Ca2+, norepinephrine / 药学学报

<p><b>AIM</b>To observe the effects of ouabain on vascular smooth muscle (VSM) of the guinea pig and its interactions with Ca2+ and norepinephrine (NE).</p><p><b>METHODS</b>Using isolated thoracic aortic ring of the guinea pig, the degrees of contractile activity of drugs were recorded.</p><p><b>RESULTS</b>Ouabain showed a direct contractile effect in a concentration-dependent manner on thoracic aortic ring of guinea pig. Ouabain shifted the NE dose-response curve to the left without changing in the maxium response. Ouabain shifted the CaCl2 dose-response curve to the left and upward, increased the maximum response to Ca2+; In Ca(2+)-free medium, the ouabain induced contraction was abolished, an increase in extracellular Ca2+ restored the response; nifedipine and verapamil abolished the ouabain induced contraction.</p><p><b>CONCLUSION</b>The ouabain induced contraction is mainly dependent on the extracellular Ca2+ concentration, independent on the presence of endothelia of aorta, suggesting that Ca2+ antagonist may treat the hypertension induced by ouabain. Ouabain, NE and CaCl2 have synergetic contractile effects, suggesting that the synergetic contractile effects of ouabain and NE may contribute to the generation and development of hypertension.</p>

Modulation of protein kinase A and protein kinase C on the delayed rectifier potassium current in guinea pig ventricular myocytes / 中国应用生理学杂志

<p><b>AIM</b>To study modulation of protein kinase A (PKA) and protein kinase C (PKC) on the delayed rectifier potassium current (Ik)in guinea pig ventricular myocytes.</p><p><b>METHODS</b>The delayed rectifier potassium current was recorded by using whole cell arrangement of the patch-clamp procedure.</p><p><b>RESULTS</b>cAMP 150 micromol/L increased intracellularly Ik and Ik,tail(pA/pF) from 13.7 +/- 2.1 and 6.1 +/- 0.1 to 18.5 +/- 3.3 and 6.4 +/- 2.1 (P < 0.01, n=6). Ik and Ik,tail(pA/pF) were augmented by 8-CPT-cAMP 150 micromol/L extracellularly from 11.4 +/- 1.8 and 5.3 +/- 0.6 to 17.9 +/- 4.0 and 6.2 +/- 1.3. The half-maximal voltage of activation of Ik was shifted from + 23.3 mV to 18.7 mV by cAMP. Phorbol 12-myristate 13-acetate(PMA, 10.0 micromol/L) applied intracellularly caused an enhance effect on Ik, with increasing Ik and Ik,tail(pA/pF) from 12.9 +/- 1.8 and 5.0 +/- 1.7 to 23.7 +/- 2.8 and 7.5 +/- 1.1. With shifting position potential of depolarization, effect of PMA on Ik was gradually augmented. PMA resulted in shifting the slop of activation curve from +15.3 mV to +25.6 mV, with only a small effect on the half-maximal voltage of activation of Ik.</p><p><b>CONCLUSION</b>Ik was increased by both PKA and PKC, with different characteristics of regulation.</p>

Effects of benzyltetrahydropalmatine on the rapidly activating component of delayed rectifier potassium current in guinea pig ventricular myocytes / 药学学报

<p><b>AIM</b>To investigate the effect of benzyltetrahydropalmatine (BTHP) on the rapidly activating component of delayed rectifier K+ current (Ikr) in single guinea pig ventricular myocytes.</p><p><b>METHODS</b>Whole-cell patch clamp technique was used to record Ikr.</p><p><b>RESULTS</b>Ikr was blocked by 1-100 mumol.L-1 BTHP in concentration-, voltage-, and specifically frequency-dependent fashion, with IC50 of 13.5 mumol.L-1 (95% confidence range: 11.2-15.8 mumol.L-1). 30 mumol.L-1 BTHP reduced Ikr and Ikr.tail by (31 +/- 4)% and (36 +/- 5)% (n = 6, P < 0.01), respectively. The time constant for deactivation (tau') of the tail current was decreased by 30 mumol.L-1 BTHP from (238 +/- 16) ms to (196 +/- 14) ms, while drug had no any effect on the time constant for activation (tau) of Ikr,tail.</p><p><b>CONCLUSION</b>BTHP inhibited Ikr in a frequency-dependent fashion.</p>