• The Journal of Internal Korean Medicine
• /
• v.34 no.2
• /
• pp.147-154
• /
• 2013

Objectives : The aims of this study was to find out whether Jichul-hwan (JCH) extract has an effect on gastric contractility in conscious rats by using a force transducer implanted in the body of the stomach. Methods : The force transducer (model: F-081S, Starmedical, JAPAN) was implanted to the exterior wall of the stomach body in rats. The gastric contractility was measured 30 minutes before and after administration of JCH (110.1 mg/kg). The control group was administrated with normal saline instead of JCH to compare the effect of JCH. The gastric contractility of the control group (normal saline: NS) was also measured 30 minutes before and after administration of NS. Results : The ratio of gastric contractility between before and after medication by JCH was $1.707{\pm}0.731$, and with NS was $0.701{\pm}0.541$. The gastric motility increased by JCH was significantly higher than NS. Conclusions : JCH extract increases gastric contractility in conscious rats. We could expect that this drug would be effective in the treatment of functional dyspepsia or post-surgical gastroparesis.

• The Korean Journal of Nuclear Medicine
• /
• v.37 no.6
• /
• pp.355-363
• /
• 2003

Purpose: Regional contractility can be calculated using the regional volume change of left ventricle measured by gated myocardial SPECT image and curve of central artery pressure obtained from radial artery pressure data. In this study, a program to obtain the regional contractility was developed, and reproducibility of regional contractility measurement was assessed. Materials and Methods: Seven patients(male:female=5:2, $58{\pm}11.9$ years) with coronary artery diseases underwent gated Tc-99m MIBI myocardial SPECT twice without delay between two scans. Regional volume change of left ventricle was estimated using CSA (Cardiac SPECT Analyzer) software developed in this study. Regional contractility was iteratively estimated from the time-elastance curve obtained using the time-pressure curve and regional time-volume curve. Reproducibility of regional contractility measurement assessed by comparing the contractility values measured twice from the same SPECT data and by comparing those measured from the pair of SPECT data obtained from a same patient. Results: Measured regional contractility was $3.36{\pm}3.38{mm}Hg/mL$ using 15-segment model, $3.16{\pm}2.25{mm}Hg/mL$ using 7-segment model, and $3.11{\pm}2.57{mm}Hg/mL$ using 5-segment model. The harmonic average of regional contractility value was almost identical to the global contractility. Correlation coefficient of regional contractility values measured twice from the same data was greater than 0.97 for all models, and two standard deviations of contractility difference on Bland Altman plot were 1.5%, 1.0%, and 0.9% for 15-, 7-, and 5-segment models, respectively. Correlation coefficient of regional contractility values measured from the pair of SPECT data obtained from a same patient was greater than 0.95 for all models, and two standard deviations on Bland Altman plot were 2.2%, 1.0%, and 1.2%. Conclusion: Regional contractility of left ventricle measured using developed software in this study was reproducible. Regional contractility of left ventricle will be a new useful index for myocardial function after analysis of the clinical data.

• The Journal of Internal Korean Medicine
• /
• v.35 no.4
• /
• pp.439-447
• /
• 2014

Objectives: The aim of this study was to investigate whether 1) variation of bowel sounds recorded stably through an electronic stethoscope in a sound insulation box can be related with that of gastric contraction and 2) if they are thus useful tool in the measurement of the gastric contractility in awake rats or not. Methods: Electrical potentials of both electronic stethoscope of bowel sound and force transducer were recorded simultaneously and continuously in the sound insulation box for the starting 30 min of basal state, and then 30 min of 0.2 ml normal saline administration, finally 30 min of 0.2 ml mosapride citrate solution (100 mg/Kg) in rats. Each motility index of normal saline or mosapride citrate treatment was presented with ratio against the basal state by using integrated electrical potentials. Results: A pattern of significance of gastric contractility between bowel sound and force transducer was showed analogously. Conclusions: The amplitude of bowel sounds recorded by the electronic stethoscope related with the intensity of gastric contractions. This confirms that a sound insulation box and electronic stethoscope are useful tools in the measurement of the gastric contractility of awake rats.

• KSBB Journal
• /
• v.26 no.3
• /
• pp.211-216
• /
• 2011

To study the effects of ethanol extract of the Rhodiola Sachalinensis on the anti-oxidation and blood pressure and skeletal muscles contractility in rats. The ethanol extracts and fractions of Rhodiola Sachalinensis were determinated the anti-oxidation effects by DPPH(1,1-dipenyl-2-picrylhydrazyl) method and comparing with the BHA (Butylated hydroxyanisole) and AA(Ascorbic acid). The gastrocnemius and soleus muscle contractility were observed by stimulating the sciatic nerve with electricity after affusing stomach with ethanol extract of the 200 mg/kg dosage of Rhodiola Sachalinensis for 4 weeks. The ethanol extract of the Rhodiola Sachalinensis could shorten latent period, increase maximal contractive extent and time and relaxative time at the twitch and complete tetanus of gastrocnemius and soleus muscles. The ethanol extract of the Rhodiola Sachalinensis shows high anti-oxidation effect and can enhance skeletal muscles contractility in rats.

• Journal of Sensor Science and Technology
• /
• v.31 no.1
• /
• pp.6-11
• /
• 2022

To date, various techniques have been utilized to assess the contractility of cardiomyocytes and their response to drug-induced toxicity. However, these techniques are either invasive or involve complex fabrication methods and expertise. Here, we introduce the use of video-based analysis software to track the motion of cardiomyocytes and assess their contractility. The software, called "Tracker", is freely available and this is the first attempt at using it for cardiac contractility measurement. We used the software to measure the contractile properties of cells cultured on a rigid substrate and two flexible polydimethylsiloxane (PDMS) substrates having different elastic moduli day-wise up to eight days. Contractility was found to be highest in the most flexible substrate. Subsequently, the cardiotoxicity response of the cells on three different substrates was analyzed with verapamil. It was observed that the cells on rigid substrate were primarily affected by drug-induced toxicity, while the drug had a lesser impact on cells on the more flexible PDMS substrate. Evidently, the flexible substrate aided the maturation of cells and had lower drug toxicity, while the cells on PS could not fully mature. The assessment of cardiomyocytes using "Tracker" proved to be simple and reliable.

• Korean Journal of Veterinary Research
• /
• v.34 no.1
• /
• pp.63-67
• /
• 1994

Berberine $(10^{-7}-10^5M)$ increased the contractility dose-dependently in isolated rabbit ileal and jejunal segments. Atropine and hemicholinium abolished this response but not mecamylamine. Berberine$(10^{-8}-10^5M)$ enhanced the transmurally-stimulated(80 V, 0.5 ms, 0.05 Hz) twitch response in the isolated guinea-pig ileal segments. Atropine and hemicholinium also abolished this response but not mecamylamine. Effect of KCI, carbachol and histamine were not affected by pretreatment with berberine$(10^{-5}M)$. The results of our study suggest that berberine increases the intestinal contractility by increasing a small amount of acetylcholine release from the postganglionic parasympathetic nerve terminal but not by a direct activation of muscarinic receptors.

• The Korean Journal of Pharmacology
• /
• v.28 no.1
• /
• pp.41-48
• /
• 1992

A concentration of 0.01 mM bupivacaine was necessary to maintain approximately 50% depression of contractility of rat atria suspended in a modified Krebs-Ringer bicarbonate glucose medium, pH 7.4 at $30^{\circ}C$. Sodium pyruvate, sodium acetate, and fructose partially restored the contractility of the bupivacaine-depressed atria. However, 20 mM glucose had no effect on the bupivacaine-depressed atria, although this concentration of glucose markedly increased the contractility of normal atria not to be exposed to bupivacaine. Contractility of normal atria was not significantly influenced by sodium pyruvate, sodium acetate, and fructose. The results suggested that at least part of the negative inotropic action of bupivacaine is the result of inhibition of glucose uptake or utilization in the glycolytic pathway, and further pinpoint the blockade as an early step in the glycolytic sequence prior to the phosphofructokinase step.

• The Korean Journal of Physiology
• /
• v.21 no.2
• /
• pp.179-189
• /
• 1987

Since it has been known that ryanodine has a potent negative inotropic effect on the cardiac muscle contractility (Jenden and Fairhurst, 1968), ryanodine has been a subject of intensive research (Frank and Sleator, 1975; Jones et al, 1978; Sutko et al, 1985). However, the underlying mechanism for the ryanodine dependent negative inotropic effect is still uncertain. In this study, the effects of ryanodine on the generation and relaxation of contracture due to Na-withdrawal and on the force-frequency relationship of heart muscles isolated from rats and guinea pigs were measured in an effort to understand the underlying mechanism of the ryanodine-induced negative inotropy. Results are summerized as follows: 1 ) Ryanodine significantly reduced the contractility of heart muscles produced at low frequency of stimulation, but showed a little effect on the contractility at high frequency stimulation. 2) Ryanodine, at the concentrations ranging from $10^{-6}\;M$ to $10^{-8}\;M$, had no significant effect on the Na-dependent relaxation of Na-withdrawl contracture. 3) Ryandoine significantly reduced the amplitude of the Na-withdrawl contracture, and this inhibitory effect was reinforced by procaine, antiagonized by caffeine and high potassium. From these results, it may be concluded that the negative inotropic effect of ryanodine is mainly due to an inhibition of calcium release from sarcoplasmic reticulum.

• The Korean Journal of Pharmacology
• /
• v.10 no.1 s.15
• /
• pp.21-39
• /
• 1974

Certain metabolic aspects of halothane's cardiac depressant action on the contractility of the myocardium were elucidated from a sudy of the effect of pyruvate on halothane-depressed rat atria. Approximately 6 mg% halothane was required to maintain a 50% depression of the contractility of rat atria suspended in a modified Krebs-Ringer bicarbonate glucose medium, pH 7.4, $30^{\circ}C$ for a 2 hr. period. Pyruvate was found to restore partially the contractility of halothane-depressed atria. The maximally effective concentration of pyruvate was 2.5 mM. There was minimal pyruvate effect on the force of contraction of control atria. The effect of pyruvate on halothane-depressed atria was shown to be due to the pyruvate and not the sodium ion of the sodium pyruvate. Pyruvate was found to produce no increase in the contractility of atria depressed by hypertonic medium, but caused a further depression. Selected aspects regarding the action of halothane on glucose metabolism in myocardial cells are discussed. The results are consistent with the hypothesis that at least a part of the negative inotropic action of halothane is due to an inhibition of glucose uptake or utilization in the glycolytic pathway.

• The Korean Journal of Physiology and Pharmacology
• /
• v.5 no.1
• /
• pp.87-92
• /
• 2001

Carbon monoxide (CO) binds to soluble guanylate cyclase to lead its activation and elicits smooth muscle relaxation. The vascular tissues have a high capacity to produce CO, since heme oxygenase-2 (HO-2) is constitutively expressed in endothelial and smooth muscle cells, and HO-1 can be greatly up-regulated by oxidative stress. Moreover, the substrate of HO, heme, is readily available for catalysis in vascular tissue. Although the activation of heme oxygenase pathway under various stress conditions may provide a defence mechanism in compromised tissues, the specific role of HO-1-derived CO in the control of aortic contractility still remains to be elucidated. The present study was done to determine the effect of HO-1 induction on the aortic contractility. Thus, the effects of incubation of aortic tissue with S-nitroso-N-acetylpenicillamine (SNAP) for 1 hr on the aortic contractile response to phenylephrine were studied. The preincubation with SNAP resulted in depression of the vasoconstrictor response to phenylephrine. This effect was restored by HO inhibitor or methylene blue but not by NOS inhibitor. The attenuation of vascular reactivity by preincubation with SNAP was also revealed in endothelium-free rings. $AlF4^--evoked$ contraction in control did not differ from that in SNP-treated group. These results suggest that increased production of CO was responsible for the reduction of the contractile response to phenylephrine in aortic ring preincubated with SNAP and this effect of SNAP was independent on endothelium.