• The Korean Journal of Physiology and Pharmacology
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• v.2 no.3
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• pp.361-368
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• 1998

The spontaneous contractions of gastric smooth muscles are regulated by slow waves, which are modulated by both nervous system and humoral agents. This study was designed to examine the effects of prostaglandin $E_2$ ($PGE_2$) on the contractile and electrical activities of antral smooth muscles in guinea-pig stomach, using an intracellular recording technique. To elucidate the underlying mechanism for its effect on contractility, ionic currents were also measured using a whole-cell patch clamp method. The basal tone by $PGE_2$ was variable, whereas the magnitude of phasic contractions was reduced ($19.0{\pm}2.1%$, n=19). The resting membrane potentials were hyperpolarized ($-4.4{\pm}0.5%$ mV, n=10), and plateau potentials were lowered ($-2.9{\pm}0.5%$ mV, n=10). In most cases, however, the initial peak potentials of slow waves were depolarized more by $PGE_2$ than those of control. The frequency of the slows wave was increased from $5.7{\pm}0.2$ cycles/min to $6.5{\pm}0.2$ (n=22). Voltage-operated $Ca^{2+}$ currents were decreased by $PGE_2$ (n=5). Voltage-operated $K^+$ currents, both Ca-dependent and Ca-independent, were increased (n=5). These results suggest that $PGE_2$ plays an important role in the modulation of gastric smooth muscle activities, and its inhibitory effects on the contractility and activities of slow waves are resulted from both decrease of $Ca^{2+}$ currents and increase of $K^+$ currents.

• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.4
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• pp.532-538
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• 2012

The aim of this study was to find correlation between EGG and HRV parameters in dyspeptic patients. 39 patients (male 8, female 31) were enrolled. EGG and HRV was measured in all patients. EGG parameters like % of gastric slow wave and power ratio were used to classify patients as normal or abnormal EGG groups. HRV parameters which were included TP (total power), LF(low frequency density), HF (high frequency density), and LF/HF ratio were compared between them. EGG parameters were compared among normal, sympathetic hyperactivity, and parasympathetic hyperactivity groups classified by LF/HF ratio. There was no difference in HRV parameters between normal and abnormal EGG groups. Comparing EGG parameters among normal, sympathetic hyperactivity, and parasympathetic hyperactivity groups, both sympathetic and parasympathetic hyperactivity groups had lower value of postprandial regularity of gastric slow wave than normal group. Abnormal value of LF/HF ratio(both sympathetic and parasympathetic hyperactivity) may be related with disturbance of electrical gastric activity in patients with dyspepsia.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.233-241
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• 1995

The nonapeptide bradykinin has been shown to exhibit an array of biological activities including relaxation/contraction of various smooth muscles. In order to investigate the effects of bradykinin on the contractility and the electrical activity of antral circular muscle of guinea-pig stomach, the isometric contraction and membrane potential were recorded. Also, using standard patch clamp technique, the $Ca^{2+}-activated$ K currents were recorded to observe the change in cytosolic $Ca^{2+}$ concentration. $0.4 {\mu}M$ bradykinin induced a triphasic contractile response (transient contraction-transient relaxation-sustained contraction) and this response was unaffected by pretreatment with neural blockers (tetrodotoxin, atropine and guanethidine) or with apamin. Bradykinin induced hyperpolarization of resting membrane potential and enhanced the amplitude of slow waves and spike potentials. The enhancement of spike potentials was blocked by neural blockers. Both the bradykinin-induced contractions and changes in membrane potential were reversed by the selective $B_2$-receptor antagonist $(N{\alpha}-adamantaneacetyl-_{D}-Arg-[Hyp, Thy,_{D}-Phe]-bradykinin)$. In whole-cell patch clamp experiment, we held the membrane potential at -20 mV and spontaneous and transient changes of Ca-activated K currents were recorded. Bradykinin induced a large transient outward current, consistent with a calcium-releasing action of bradykinin front the intracellular calcium pool, because such change was blocked by pretreatment with caffeine. Bradykinin-induced contraction was also blocked by pretreatment with caffeine. From these results, it is suggested that bradykinin induces a calciumrelease and contraction through the $B_{2}$ receptor of guinea-pig gastric smooth muscle. Enhancement of slow wave activity is an indirect action of bradykinin through enteric nerve cells embedded in muscle strip.

• The Journal of the Society of Korean Medicine Diagnostics
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• v.12 no.1
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• pp.131-141
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• 2008

Background: In relation to a diagnosis of Korean Medicine, heat-cold is one of the most important indicators for evaluation. In spite of this importance, there has not been the study that tries to examine the change of indicators in an electrogastrography (EGG) according to the heat-cold patternization. Objective: The objective of this study is to establish the correlation between the heat-cold patternization and indicators of EGG by means of Standardized Questionnaire for Heat-Cold Patternization. Method: To conduct this study, we used the method as follows: Before conducting EGG, subjects were requested to give answers to the questionnaire which was developed by Kim. Before EGG, subjects were demanded to fast for more than 8 hours and then eat the test meal. Before eating the test meal(test meal: two slices of bread, 4oz of apple juice), EGG signals were detected for 30 minutes, and then subjects could eat the test meal for 10 minutes. After eating the test meal, EGG signals were detected for 30 minutes. Results: 1. There was a negative correlation between heat score and the power ratio of channel 1 and channel 2 of EGG. There was a positive correlation between cold score and the power ratio of channel 1 of EGG. 2. There was a positive correlation between heat score and pre-prandial gastric arrhythmia in the channel 1, 2 and 4 of EGG. There was a negative correlation between cold score and post-prandial gastric arrhythmia in the channel 1, 2 and 3 of EGG. 3. There was a negative correlation between heat score and normal pre-prandial gastric slow wave in the channel 1, 2 and 4 of EGG. There was a positive correlation between cold score and normal post-prandial gastric slow wave in the channel 3 of EGG. Conclusions: From the results above, we could conclude as follows: Indicators of EGG and cold score presented a positive correlation, and heat score displayed a negative correlation. As a result, to apply EGG to a diagnosis of functional indigestion, the application of EGG to subjects who have heat patternization would increase the reliability of a diagnosis.

• The Journal of Korean Medicine
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• v.24 no.4
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• pp.92-101
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• 2003

Background ＆ Aims : The aim of this study was to investigate the change of dominant power with observation of gastric myoelectrical activity and its parameter linkage in electrogastrography. Methods : Electrogastrography was performed on a total of 123 subjects (113 patients with functional dyspepsia, 10 healthy controls) for 30 min in fasting state and 50 min in postprandial state. Average myoelectrical activity per frequency and accumulated electrical activity of 5 min duration in each bradygastria, normogastria, and tachygastria were measured at the moment of frequency switchover of slow wave. Assumed parameter linkages were also investigated among dominant frequency, ％ of normal regularity, and dominant power (or power ratio). Results : Average myoelectrical activity per frequency was highest in bradygastria (mean 1.10-1.47 Volt/s), next highest in normogastria (mean 0.50-0.82 Volt/s), and lowest in tachygastria (mean 0.44-0.47 Volt/s). Average accumulated myoelectrical activity was highest in normogastria (mean 114.90-126.29 Volt/ss), next highest in tachygastria (mean 71.02-90.00 Volt/ss), and lowest in bradygastria (mean 12.93-51.94 Volt/ss). Significance of parameter linkages were noted in dominant frequency (p< 0.01) and in ％ of normal regularity (p< 0.01), but not in dominant power in case of frequency shift from bradygastria to normogastria (p=0.376). Conclusion : Dominant power is not a parameter that reflects the gastric myoelectrical activity related with only gastric contraction. Bradygastric dominant power does not follow the inter-parameter linkage of electrogastrography for gastric motility assessment.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.1
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• pp.152-157
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• 2010

The aim of this study was to investigate the effects of traditional Korean medical therapy in patients with functional dyspepsia evaluted using multi-channel electrogastrography. Before the treatment, the EGG of 14 outpatients (male 3, female 11) with functional dyspepsia were recorded and their dominant frequency(DF), percentage of gastric slow waves, percentage of Power ratio, and percentage of slow wave couplings were analysed. For 8 weeks, the patients received acupuncture treatment. After 8 weeks, EGG was rechecked and compared with the previous data. After treatment, normogastria was significantly increased in channel 1 and channel 3($53.70{\pm}18.94$% vs $72.64{\pm}15.49$% in channel 1, P<0.05; $79.74{\pm}18.09$ vs $90.86{\pm}8.86$ in channel 3, P<0.05). arrythmia was significantly decreased in channel 3($14.34{\pm}15.21$ vs $5.93{\pm}6.90$, P<0.05). The patients who had less severe decrease in EGG indexes showed improvement of those indexes through 8 weeks of outpatient care. EGG channel 3 was shown to be the most adequate standard of evaluation. But there was no significant improvement in slow wave coupling rate which is a new index of multichannel EGG.

• The Korean Journal of Physiology
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• v.24 no.1
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• pp.39-49
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• 1990

It has been reported that bombesin induces contraction of the smooth muscle of the gastrointestinal tract. Thus, the present investigation was undertaken to see an influence of bombesin on electrical activity of the gastric smooth muscle, since electrical activity is associated with contractile activity in the smooth muscle of the stomach. Smooth muscle strips $(5\;{\times}\;1.5\;cm)$ that included the corpus and antrum were prepared from the ventral and dorsal portion of the feline stomach along the greater curvature. Circular muscle strips $(1\;{\times}\;0.3\;cm)$ of the corpus were also obtained. Electrical activity of the corpus and antrum of the muscle strip was monophasically recorded by using Ag-AgCl capillary electrodes placed on the circular muscle layer. Contractile activity of the circular muscle strip was also recorded. The recordings were performed in Krebs-Ringer solution that was continuously aerated with $O_{2}$ containing 5% $Co_{2}$, and kept at $36^{\circ}C$. Dose-related responses of electrical activity and contractility to bombesin was studied after frequency of slow waves and contraction of each strip reached to a steady state. An action of $D-leu^{13}-{\psi}\;(CH_{2}NH)-D-leu^{14}-bombesin,\;D-pro^{2}-D-trp^{7,9}-substance\;P$, tetrodotoxin, hexamethonium, atropine, phentolamine or propranolol on the effect of bombesin was also observed. 1) Bombesin increased frequency of slow waves and contractions dose-dependently at concentrations from $10^{-9}\;M\;to\;3\;{\times}\;10^{-8}\;M$. 2) The bombesin analogue at a concentration of $3\;{\times}\;10^{-7}\;M$ antagonized the effect of bombesin on frequency of slow waves. 3) The effect of bombesin on frequency of slow waves was inhibited by tetrodotoxin $(10^{-6}\;M)$ and hexamethonium $(10^{-3}\;M)$ but unaffected by atropine $(10^{-6}\;M)$, phentolamine $(10^{-5}\;M)$ and propranolol $(10^{-5}\;M)$. 4) The effect of bombesin on frequency of slow waves was blocked by the substance P analogue at a concentration of $10^{-5}\;M$. 5) Substance P at a concentration of $10^{-5}\;M$ failed to change frequency of slow waves. It is concluded from the above results that bombesin increases the frequency of slow waves as well as contractions of the smooth muscle strip from the feline stomach, and the effect of bombesin might be mediated by non-cholinergic or non-adrenergic mechanism at neuromuscular junction. However, enteric nerves that have substance P as a neurotransmitter do not appear to participate in the action of bombesin on frequency of slow waves.

• The Journal of Internal Korean Medicine
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• v.26 no.2
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• pp.360-368
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• 2005

Background & Object: The aim of this study was to investigate the effects of Traditional Korean medical therapy on gastric myoelectrical activity in patients with functional dyspepsia. Methods: 29 patients(male 10, female 19) were divided into two groups; Inpatient group(N=10, male 1, female 9) and outpatient group(N=19, male 9, female 10). 10 healthy people participated in this study as normal controls. Gastric motility was recorded and analyzed by electrogastrography(EGG) during fasting and postprandial periods. Hospital treatment included electroacupuncture on ST36, acupuncture, and herbal medicine. Outpatients were treated with herbal medicine and acupuncture. Inpatients underwent hospital treatment for two weeks, and after discharge they were treated as outpatients for six weeks. In inpatient group, EGG was recorded before and after hospital treatment and it was recorded at six weeks after discharge. In outpatient group, EGG was recorded before starting treatment and it was recorded once a every six weeks for twelve weeks. Results: There was no significant difference in EGG parameters between before and after therapy in outpatient group. In inpatient group, postprandial normal slow wave increased after hospital treatment(from $33.94{\pm}14.13$ to $62.63{\pm}20.18$, p<0.05) and postprandial tachygastria decreased(from $43.53{\pm}13.99$ to $28.30{\pm}16.63$, p<0.05) and arrhythmia decreased(from $20.35{\pm}15.91$ to $5.67{\pm}6.80$, p<0.05). Conclusions: Results suggest that hospital treatment through electroacupuncture on ST36, acupuncture, and herbal medicine is useful to improve gastric myoelectrical activity in Patients with Functional Dyspepsia.

• The Korean Journal of Physiology
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• v.28 no.1
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• pp.37-50
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• 1994

Synthetic potassium channel openers (KCOs) are agents capable of opening K-channels in excitable cells. These agents are known to have their maximal potency in the smooth muscle tissue, especially in the vascular smooth muscle. Much attention has been focused on the type of K-channel that is responsible for mediating the effects of KCOs. As the KCO-induced changes are antagonized by glibenclamide, an $K_{ATP}$ (ATP-sensitive K-channel) blocker in the pancreatic ${\beta}-cell,\;K_{ATP}$ was suggested to be the channel responsible. However, there also are many results in favor of other types of K-channel $$(maxi-K,\;small\;conductance\;K_{Ca,}\; SK_{ATP}) mediating the effects of KCOs. Effects of lemakalim, (-)enantiomer of cromakalim (BRL 34915), on the spontaneous contractions and slow waves, were investigated in the antral circular muscle of the guinea-pig stomach. Membrane currents and the effects on membrane currents and single channel activities were also measured in single smooth muscle cells and excised membrane patches by using the patch clamp method. Lemakalim induced hyperpolarization and inhibited spontaneous contractions in a dose-dependent manner. These effects were blocked by glibenclamide and low concentrations of tetraethyl ammonium (< mM). Glibenclamide blocked the effect of lemakalim on the membrane potential and slow waves. The mechanoinhibitory effect of lemakalim was blocked by pretreatment with glibenclamide. In a whole ceIl patch clamp condition, lemakalim largely increased outward K currents. These outward K currents were blocked by TEA, glibenclamide and a high concentration of intracelIular EGTA (10 mM). Volatage-gated Ca currents were not affected by lemakalim. In inside-out patch clamp experiments, lemakalim increased the opening frequency of the large conductance $Ca^{2+}-activated$ K channels $(BK_{Ca},\;Maxi-K).$ From these results, it is suggested that lemakalim induces hyperpolarization by opening K-channels which are sensitive to internal Ca and such a hyperpolarization leads to the inhibition of the spontaneous contraction.