Effect of different immunization schedules on diphtheria antibody level among preschool children in Shenzhen / 中国学校卫生

Objective@#To evaluate the immunity and influencing factors of diphtheria among preschool children in Shenzhen,to provide reference for effective monitoring of diphtheria IgG antibody level in preschool children.@*Methods@#Serum samples were collected from 296 preschool children aged 4-6 who were recruited in Shenzhen. The diphtheria antibody titer in serum was determined by enzyme linked immunosorbent assay, and the effect of different immumuzation schedule including types of vaccine and vaccination timing, on the geometric mean concentration (GMC) of diphtheria IgG antibody and antibody positive rate were analyzed.@*Results@#The GMC of diphtheria IgG antibody was 0.71 IU/mL, and the positive conversion rate was 33.1%. There were significant differences in antibody GMC and antibody positive conversion rate of diphtheria in different age groups( F/χ 2=11.77, 27.45, P < 0.01 ). The GMC and antibody positive conversion rate showed significant differences by diphtheria antibodies, vaccine types and end dose vaccination intervals( F=49.53, 12.95，11.61, P <0.01). There were statistically significant differences in the positive conversion rate of diphtheria antibodies in children with different types of diphtheria antibodies, vaccine types of diphtheria antibodies, and diphtheria antibodies at the time interval of final vaccination (Fisher exact probability method, P <0.01).@*Conclusion@#The overall positive conversion rate of diphtheria antibody in preschool children in Shenzhen is high. Timely completion of full diphtheria vaccination can improve the antibody level and plays a better role in protecting preschool children.

Protein Kinase CK2 Modulates the Calcium Sensitivity of Type 3 Small-conductance Calcium-activated Potassium Channels in Colonic Platelet-derived Growth Factor Receptor Alpha-positive Cells From Streptozotocin-induced Diabetic Mice

Background/Aims@#The gastrointestinal symptom of diabetes mellitus, chronic constipation, seriously affects patients’ life. Whereas, the mechanism of chronic constipation is still ambiguous, resulting in a lack of effective therapies for this symptom. As a part of the smooth muscle cells, interstitial cells of Cajal, and platelet-derived growth factor receptor alpha-positive (PDGFRα+ ) cells syncytium (SIP syncytium), PDGFRα+ cells play an important role in regulating colonic motility. According to our previous study, in PDGFRα+cells in colons of diabetic mice, the function of the P2Y1 purinergic receptor/type 3 small-conductance calcium-activated potassium (SK3) channel signaling pathway is strengthened, which may lead to colonic dysmotility. The purpose of this study is to investigate the changes in SK3 channel properties of PDGFRα+ cells in diabetic mice. @*Methods@#Whole-cell patch clamp, Western blotting, superoxide dismutase activity measurement, and malondialdehyde measurement were main methods in the present study. @*Results@#The present study revealed that when dialysed with low calcium ion (Ca 2+ ) solution, the SK3 current density was significantly decreased in PDGFRα+ cells from diabetic mice. However, the SK3 current density in PDGFRα+ cells was enhanced from diabetic mice when dialysed with high Ca 2+ solution. Moreover, hydrogen peroxide-treatment mimicked this phenomenon in SK3 transgenic HEK293 cells. The subunit of SK3 channels, protein kinase CK2, was up-regulated in colonic muscle layers and hydrogen peroxidetreated HEK293 cells. Additionally, protein phosphatase 2A, the subunit of SK3 channels, was not changed in streptozotocin-treated mouse colons or hydrogen peroxide-treated HEK293 cells. @*Conclusion@#The diabetic oxidative stress-induced upregulation of CK2 contributed to modulating SK3 channel sensitivity to Ca 2+ in colonic PDGFRα+ cells, which may result in colonic dysmotility in diabetic mice.

Research progress on total skin irradiation using helical tomotherapy / 中华放射肿瘤学杂志

Cutaneous T-cell lymphomas are a relatively rare group of mature T-cell lymphomas mainly manifesting in the skin, and its common subtype is mycosis fungoides. Total skin electron irradiation is one of the important conventional treatment methods, but there are many disadvantages, such as uneven dose distribution, poor position repetition, and long treatment time, which affect the clinical efficacy and patient prognosis. With the emergence and gradual popularization of helical tomotherapy in recent years, more and more medical institutions are gradually expanding their applications in total skin irradiation due to their ability to treat ultra-long targets and achieve dose-sculpted distribution, aiming to further explore its good or bad, and confirm whether it can replace the traditional total skin electron irradiation. In this article, research progress on total skin irradiation using helical tomotherapy was reviewed, the development of treatment technology, clinical efficacy and current concerns and controversies were illustrated.

Personalized quantitative evaluation of the quality of radiotherapy plans based on dose prediction / 中华放射医学与防护杂志

Objective:To develop a dose prediction-based quantitative evaluation method of the quality of radiotherapy plans, and to verify the clinical feasibility and clinical value of the method .Methods:The 3D U-Netwas trained using the radiotherapy plans of 45 rectal cancer cases that were formulated by physicists with more than five years of radiotherapy experience. After obtaining 3D dose distribution using 3D U-Net prediction, this study established the plan quality metrics of intensity modulated radiotherapy(IMRT) rectal cancer radiotherapy plans using dose-volume histogram(DVH) indexes of dose prediction. Then, the initial scores of rectal cancer radiotherapy plans were determined.Taking the predicted dose as the optimization goal, the radiotherapy plans were optimized and scored again. The clinical significance of this scoring method was verified by comparing the scores and dosimetric parameters of the 15 rectal cancer cases before and after optimization.Results:The radiotherapy plans before and after optimization all met the clinical dose requirements. The total scores were(77.21±9.74) before optimization, and (88.78±4.92) after optimization. Therefore, the optimized radiotherapy planswon increased scores with a statistically significant difference( t=-4.105, P<0.05). Compared to the plans before optimization, the optimized plans show decreased Dmax of all organs at risk to different extents. Moreover, the Dmax, V107%, and HI of PTV and the Dmax of the bladder decreased in the optimized plans, with statistically significant differences ( t=2.346-5.771, P<0.05). There was no statistically significant difference in other indexes before and after optimization ( P>0.05).The quality of the optimized plans were improved to a certain extent. Conclusions:This study proposed a dose prediction-based quantitative evaluation method of the quality of radiotherapy plans. It can be used for the effective personalized elevation of the quality of radiotherapy plans, which is beneficial to effectively compare and review the quality of clinical plans determined by different physicists and provide personalized dose indicators. Moreover, it can provide great guidance for the formulation of clinical therapy plans.

Self-adjustable automatic planning method of intensity modulated radiotherapy based on 3D predicted dose / 中华放射医学与防护杂志

Objective:To develope a self-adjustable automatic planning method of intensity modulated radiotherapy based on predicted dose, in order to enhance the robustness of automatic planning.Methods:After the patients′ dose by 3D U-Res-Net_B network was predicted, the current dose was calculated based on the last iteration result, then the predicted dose was combined to calculate the target dose and optimized. With all iterations completed or exit conditions satisfied, final treatment plannings would be acquired. A total of 30 cases of rectal cancer were tested to verify the effectiveness of the algorithm.Results:The mean value of planning target volumes′ V100% was (95.03±0.91)% for clinical plans, close to (94.67±1.96)% for automatical plans( P>0.05), and better than (92.90±2.13)% for predicted dose with the statisically significant difference ( t=29.0, P<0.05). Automatic planning′s indexes such as V35 of small intestines, V40 of bladders and V20 - V40 of femoral heads were lower than predicted and clinical ones, with the statisically significant difference( t=4.5-118.0, P<0.05). Discrepancy in other indexes of organs at risk was not statistically significantly different( P>0.05). Conclusions:This method made automatic planning processes more robust and more adaptive to difficult clinical situations.

Role of platelet-derived growth factor receptor α positive cells in purinergic inhibitory nerve-smooth muscle transmission / 生理学报

Under physiological conditions, the motility of smooth muscle in digestive tract is mainly regulated by enteric nervous system (ENS). However, how neural signal is transmitted to smooth muscle is not fully understood. Autonomic nerve endings in the smooth muscle layer form large number of varicosities which contain neurotransmitters. It was considered that nerve pulses arriving at the varicosities may cause the release of neurotransmitters, which may diffuse to the smooth muscle cells to induce contractile or relaxant responses. Over the past decade, a new understanding of the neurotransmission between ENS and smooth muscle has emerged, which emphasizes the role of a functional syncytium consisting of the interstitial cells of Cajal (ICC), the platelet-derived growth factor receptor α positive (PDGFRα) cells and the smooth muscle cells. Within the syncytium, purine neurotransmitters bind to P2Y1 receptors on PDGFRα cells, activating small-conductance calcium activated potassium channel (SK3) to hyperpolarize PDGFRα cells, and thus hyperpolarize smooth muscle cells through gap junction, resulting in relaxation of smooth muscle. In this paper, we review the research progress in the field of inhibitory purinergic neurotransmission in the gastrointestinal tract.

Robust optimization of intensity-modulated proton therapy for range uncertainty / 中华放射肿瘤学杂志

Objective Because of high precision and mild side effects,intensity-modulated proton therapy (IMPT) has become a hot spot in the radiotherapy field.Nevertheless,the precision of IMPT is extremely sensitive to the range uncertainties.In this paper,a novel robust optimization method was proposed to reduce the effect of range uncertainty upon IMPT.Methods Firstly,the robust optimization model was established which contained three types of range including the increased range,the normal range and the shortened range.The objective function was expressed in quadratic function.The organ dose contribution matrix of each range was calculated by proton pencil beam algorithm.The range deviation was discretized and the probability of each range was obtained based on the Gauss distribution function.Finally,the conjugate gradient method was adopted to find the optimal solution to make the actual dose coverage of the target area and the organs at risk distributed within the expected dose as possible.Results The 3 sets of simulation tests provided by the AAPM TG-119 Report were utilized to evaluate the effectiveness of this method:nasopharyngeal carcinoma,prostate and "C"-type cases.Compared with conventional IMPT optimization approach,this novel method was less sensitive to the range uncertainty.When the range deviation occurred,the dose coverage of the target area and organs at risk of the nasopharyngeal carcinoma and prostate cases almost reached the expected dose,and the high dose coverage of the target area and organs at risk protection were improved in the"C"-type cases.Conclusions To compensate for the range uncertainty,this novel method can enhance the dose coverage of the target area and reduce the dose coverage of the organs at risk.

Monte Carlo simulation of whole body dose distribution in patients with total body X (γ) ray irradiation / 中华放射肿瘤学杂志

Objective To explore the feasibility of application of the Monte Carlo method to simulate the whole body dose distribution in patients with total body X (γ) ray irradiation by comparing the actual measurement results.Methods A Monte Carlo model of a 6 MV Elekta Synergy Clinical linear accelerator was established by MCNPX.According to the relationship between the CT value and the density of the material,the CT of the ATOM physical phantom was converted into a voxel phantom for MCNPX calculation.The dose distribution of the whole body was simulated in the total body X (γ) ray irradiation.The simulated results were compared with the measurement values of the thermoluminescence dosimetry at different positions in the ATOM physical phantom to analyze the differences.Results The difference between the depth dose curve and the off-axis dose curve and the actual measurement values calculated by the 6 MV accelerator treatment head model in the water tank was less than 2％,with the maximum dose depth of approximately 1.5 cm and field size of 10 cm× 10 cm,which were consistent with the actual measurement values.The maximum difference between the simulated results at different locations in the body and the thermoluminescence dosimeter was approximately 4％,and the simulated results of MCNPX were almost in good agreement with the results of thermoluminescence.Conclusions The whole body dose distribution in patient with total body X (γ) ray irradiation can be accurately simulated by MCNPX.Monte Carlo simulation makes it possible to optimize the uniformity of the total body dose during the total body irradiation process.

Construction of hidden curriculum in the academic experience inheritance of distinguished TCM veteran doctors / 中国针灸

To discuss the advantages and necessity of hidden curriculum construction in the academic experience inheritance of distinguished TCM veteran doctors by analyzing the characteristics of the hidden curriculum and the academic experience inheritance of distinguished TCM veteran doctors, and put forward viewpoints and pathways of promoting academic experience inheritance of distinguished TCM veteran doctors through the construction of hidden curriculum，such as optimal design of teaching environment，reasonable planning of teaching content and development of teaching information model，to effectively improve student cultivation quality and achieve the TCM talent cultivation goal which clinical diagnosis and treatment skills and clinical innovation ability are the core.

The study of automatic treatment planning of prostate cancer based on DVH prediction models of organs at risk / 中华放射肿瘤学杂志

Objective To evaluate the feasibility of utilizing dose-volume histogram (DVH) prediction models of organs at risk (OARs) to deliver automatic treatment planning of prostate cancer.Methods The training set included 30 cases randomly selected from a database of 42 cases of prostate cancer receiving treatment planning.The bladder and rectum were divided into sub-volumes (Ai) of 3 mm in layer thickness according to the spatial distance from the boundary of planning target volume (PTV).A skewed normal Gaussian function was adopted to fit the differential DVH of Ai,and a precise mathematical model was built after optimization.Using the embedded C++ subroutine of Pinnacle scripa,ahe volume of each Ai of the remaining validation set for 12 patients was obtained to predict the DVH parameters of these OARa,ahich were used as the objective functions to create personalized Pinnacle script.Finalla,automatic plans were generated using the script.The dosimetric differences among the original clinical plannina,aredicted value and the automatic treatment planning were statistically compared with paired t-test.Results DVH residual analysis demonstrated that predictive volume fraction of the bladder and rectum above 6 000 cGy were lower than those of the original clinical planning.The automatic treatment planning significantly reduced the V70,V60,V50 of the bladder and the V70 and V60 of the rectum than the original clinical planning (all P＜0.05),the coverage and conformal index (CI) of PTV remained unchangea,and the homogeneity index (HI) was slightly decreased with no statistical significance (P＞ 0.05).Conclusion The automatic treatment planning of the prostate cancer based on the DVH prediction models can reduce the irradiation dose of OARs and improve the treatment planning efficiency.

Laparoscopic camera navigation training for medical students / 基础医学与临床

Objective To investigate the performance of laparoscopic camera navigation training for medical students using the virtual reality simulator .Methods Ten medical clerks ( group A ) , 10 medical interns ( group B ) and 10 first year surgical residents (group C) are randomly enrolled in this study , and 10 surgical attendings (group D) are enrolled as control group .The performance of pre-training and post-training is analyzed .Results The performance of pre-training and post-training in the same group was significant improved ( P<0.05) and there was significant differ-ence among group A , B and C, also there was significant difference between the training group and the surgical at -tendings (control group) (P<0.05), respectively.Conclusions The laparoscopic camera navigation skills can be improved by laparoscopic virtual reality simulator especially for the medical interns and surgical residents .

Optimization of DXA lumber spine bone imaging parameters based on Monte Carlo method and CT voxel phantom / 中华放射医学与防护杂志

Objective@#To study the lumber spine imaging process of dual-energy X-ray absorptiometry (DXA) and parameters used to optimize the image quality.@*Methods@#A computational voxel phantom was constructed from patient computed tomography (CT) data. Using the Monte Carlo radiation transport method, a dual energy x-ray beam was simulated to scan the phantom of lumbar spine to generate a bone density image. The Figure of Merit (FOM) of each image was claculated. Parameters including the combination of the high and low energy tube voltage, the thickness of Cu filter, and the ratio of two beam energy incident photon number were optimized, which based on FOM.@*Results@#FOM reaches a minimum of 1.59 × 10-2 with the tube voltage combination of 75 and 200 kVp. With the thickness of the Cu filter from 0 mm to 3 mm, FOM decreases from 6.30×10-2 to 1.87×10-2, showing a gradually slow-down trend. With the incident photon number ratio (low energy/high energy) increasing from 1∶3 to 19∶1, FOM decreases firstly and then increases, reaching a minimum of 1.40×10-2 at 3∶1.@*Conclusions@#According to the simulation results, the combinations of low tube voltage from 70 kVp to 85 kVp and high tube voltage from 160 kVp to 200 kVp, 0.3 mm Cu filter and beam incident photon number ratio from 1 to 5 can yield the best lumbar spine image quality with the lowest patient dose.

Treatment of Lumbar Disc Herniation with Acupressure-Rubbing Method based on the Theory of "Waist is the Storehouse of Kidney" / 世界科学技术-中医药现代化

Objective: To observe the clinical effect of lumbar disc herniation (LDH) treatment with acupressure-rubbing method based on the theory of"Waist is the Storehouse of Kidney". Methods: A total of 120 patients with LDH were randomly divided into control group and treatment group, with 60 cases in each group. The control group was treated with prone position and lumbar extension. The treatment group was treated with acupressure-rubbing method. All the patients were given treatment once a day and it was continuous for 2 weeks, then the corresponding curative effect was evaluated after experiment. Results: The overall clinical efficacy, waist JOA scores and VAS scores of the treatment group were better than those of the control group (P ＜ 0.05) . Conclusion: The mechanism of acupressure-rubbing method curing LDH may be through regulating the body.s immune system to achieve the effect of"benefiting kidney for relieving pain"and it is worthy of clinical application and in-depth research.

Development of the software package VirtualDose-IR for evaluating radiation doses to patients during interventional procedure / 中华放射医学与防护杂志

Objective To develop an online organ doses reporting software VirtualDose-IR, which can compute the radiation doses and provide an easy access to evaluation and control of patients ′radiation doses.Methods Monte Carlo method was applied to simulating various interventional radiology ( IR) processes , which included various parameters such as different patient models at different ages and with different weights , different projection angles and regions of interest , and other parameters .All of the dose data was acquired and then integrated into a database , and displayed with hyper text markup language (HTML), so only a web browser was necessary for users .Results A web-based software that reports organ doses for patients under IR progress was developed .The organ doses assessed with VirtualDose-IR were compared with other experiment and simulation data , and the results were basically consistent with each other .Conclusions VirtualDose-IR is a easy and efficient method to assess patients′radiation doses of IR.

Physiological and pathophysiological meanings of gastrointestinal smooth muscle motor unit SIP syncytium / 生理学报

Gastrointestinal smooth muscle layer contains two kinds of interstitial cells with special differentiation, i.e., interstitial cells of Cajal (ICC) and platelet-derived growth factor receptor α-positive (PDGFRα) cells. The ICC and PDGFRαcells contact with smooth muscle cells (SMCs) by gap junctions and regulate contractive function of the SMCs. Therefore, these three kinds of cells constitute a functional syncytium, i.e., the SMC, ICC and PDGFRαcells syncytium (SIP syncytium). Various neurotransmitters, humoral factors, endogenous bioactive molecules, as well as drugs regulate gastrointestinal motility through the SIP syncytium. In this review, we introduce the concept of SIP syncytium and summarize functions of the syncytium, as well as its physiological and pathological significances.

Myometrial relaxation of mice via expression of two pore domain acid sensitive K⁺ (TASK-2) channels

Myometrial relaxation of mouse via expression of two-pore domain acid sensitive (TASK) channels was studied. In our previous report, we suggested that two-pore domain acid-sensing K⁺ channels (TASK-2) might be one of the candidates for the regulation of uterine circular smooth muscles in mice. In this study, we tried to show the mechanisms of relaxation via TASK-2 channels in marine myometrium. Isometric contraction measurements and patch clamp technique were used to verify TASK conductance in murine myometrium. Western blot and immunehistochemical study under confocal microscopy were used to investigate molecular identity of TASK channel. In this study, we showed that TEA and 4-AP insensitive non-inactivating outward K⁺ current (NIOK) may be responsible for the quiescence of murine pregnant longitudinal myometrium. The characteristics of NIOK coincided with two-pore domain acid-sensing K⁺ channels (TASK-2). NIOK in the presence of K⁺ channel blockers was inhibited further by TASK inhibitors such as quinidine, bupivacaine, lidocaine, and extracellular acidosis. Furthermore, oxytocin and estrogen inhibited NIOK in pregnant myometrium. When compared to non-pregnant myometrium, pregnant myometrium showed stronger inhibition of NIOK by quinidine and increased immunohistochemical expression of TASK-2. Finally, TASK-2 inhibitors induced strong myometrial contraction even in the presence of L-methionine, a known inhibitor of stretch-activated channels in the longitudinal myometrium of mouse. Activation of TASK-2 channels seems to play an essential role for relaxing uterus during pregnancy and it might be one of the alternatives for preventing preterm delivery.

H2 Receptor-Mediated Relaxation of Circular Smooth Muscle in Human Gastric Corpus: the Role of Nitric Oxide (NO)

This study was designed to examine the effects of histamine on gastric motility and its specific receptor in the circular smooth muscle of the human gastric corpus. Histamine mainly produced tonic relaxation in a concentration-dependent and reversible manner, although histamine enhanced contractility in a minor portion of tissues tested. Histamine-induced tonic relaxation was nerve-insensitive because pretreatment with nerve blockers cocktail (NBC) did not inhibit relaxation. Additionally, K+ channel blockers, such as tetraethylammonium (TEA), apamin (APA), and glibenclamide (Glib), had no effect. However, N(G)-nitro-L-arginine methyl ester (L-NAME) and 1H-(1,2,4)oxadiazolo (4,3-A) quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase (sGC), did inhibit histamine-induced tonic relaxation. In particular, histamine-induced tonic relaxation was converted to tonic contraction by pretreatment with L-NAME. Ranitidine, the H2 receptor blocker, inhibited histamine-induced tonic relaxation. These findings suggest that histamine produced relaxation in circular smooth muscle of human gastric smooth muscle through H2 receptor and NO/sGC pathways.

Mechanism of Relaxation Via TASK-2 Channels in Uterine Circular Muscle of Mouse

Plasma pH can be altered during pregnancy and at labor. Membrane excitability of smooth muscle including uterine muscle is suppressed by the activation of K+ channels. Because contractility of uterine muscle is regulated by extracellular pH and humoral factors, K+ conductance could be connected to factors regulating uterine contractility during pregnancy. Here, we showed that TASK-2 inhibitors such as quinidine, lidocaine, and extracellular acidosis produced contraction in uterine circular muscle of mouse. Furthermore, contractility was significantly increased in pregnant uterine circular muscle than that of non-pregnant muscle. These patterns were not changed even in the presence of tetraetylammonium (TEA) and 4-aminopyridine (4-AP). Finally, TASK-2 inhibitors induced strong myometrial contraction even in the presence of L-methionine, a known inhibitor of stretchactivated channels in myometrium. When compared to non-pregnant myometrium, pregnant myometrium showed increased immunohistochemical expression of TASK-2. Therefore, TASK-2, seems to play a key role during regulation of myometrial contractility in the pregnancy and provides new insight into preventing preterm delivery.

High K(+)-Induced Relaxation by Nitric Oxide in Human Gastric Fundus

This study was designed to elucidate high K(+)-induced relaxation in the human gastric fundus. Circular smooth muscle from the human gastric fundus greater curvature showed stretch-dependent high K+ (50 mM)-induced contractions. However, longitudinal smooth muscle produced stretch-dependent high K(+)-induced relaxation. We investigated several relaxation mechanisms to understand the reason for the discrepancy. Protein kinase inhibitors such as KT 5823 (1 microM) and KT 5720 (1 microM) which block protein kinases (PKG and PKA) had no effect on high K(+)-induced relaxation. K+ channel blockers except 4-aminopyridine (4-AP), a voltage-dependent K+ channel (KV) blocker, did not affect high K(+)-induced relaxation. However, N(G)-nitro-L-arginine and 1H-(1,2,4)oxadiazolo (4,3-A)quinoxalin-1-one, an inhibitors of soluble guanylate cyclase (sGC) and 4-AP inhibited relaxation and reversed relaxation to contraction. High K(+)-induced relaxation of the human gastric fundus was observed only in the longitudinal muscles from the greater curvature. These data suggest that the longitudinal muscle of the human gastric fundus greater curvature produced high K(+)-induced relaxation that was activated by the nitric oxide/sGC pathway through a KV channel-dependent mechanism.

Nitric Oxide-mediated Relaxation by High K+ in Human Gastric Longitudinal Smooth Muscle

This study was designed to elucidate high-K+induced response of circular and longitudinal smooth muscle from human gastric corpus using isometric contraction. Contraction from circular and longitudinal muscle stripes of gastric corpus greater curvature and lesser curvature were compared. Circular smooth muscle from corpus greater curvature showed high K+ (50 mM)-induced tonic contraction. On the contrary, however, longitudinal smooth muscle strips showed high K+ (50 mM)-induced sustained relaxation. To find out the reason for the discrepancy we tested several relaxation mechanisms. Protein kinase blockers like KT5720, PKA inhibitor, and KT5823, PKG inhibitor, did not affect high K+-induced relaxation. K+ channel blockers like tetraethylammonium (TEA), apamin (APA), glibenclamide (Glib) and barium (Ba2+) also had no effect. However, N(G)-nitro-L-arginine (L-NNA) and 1H-(1,2,4) oxadiazolo (4,3-A) quinoxalin-1-one (ODQ), an inhibitor of soluble guanylate cyclase (sGC) and 4-AP (4-aminopyridine), voltage-dependent K+ channel (KV) blocker, inhibited high K+-induced relaxation, hence reversing to tonic contraction. High K+-induced relaxation was observed in gastric corpus of human stomach, but only in the longitudinal muscles from greater curvature not lesser curvature. L-NNA, ODQ and KV channel blocker sensitive high K+-induced relaxation in longitudinal muscle of higher portion of corpus was also observed. These results suggest that longitudinal smooth muscle from greater curvature of gastric corpus produced high K+-induced relaxation which was activated by NO/sGC pathway and by KV channel dependent mechanism.