• Biomolecules & Therapeutics
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• v.9 no.2
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• pp.119-124
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• 2001

In order to determine the role of dehydroepiandrosterone (DHEA), the important sex-steroid hormone precursor, in vascular reactivity in rats, animals were treated for two weeks with DHEA or sex hormones, and the vascorelaxant and contractile responses of isolated aorta were examined. DHEA diminished the acetylcholine (ACh)-induced relaxation in female rats, while the drug was without effect in males. Testoterone lowered the vasorelaxant activity to ACh in either sex. 17$\beta$-Estradiol enhanced ACh-induced vasorelaxation in male rats, but this female sex hormone did not influence in females. In male rats, the androgen receptor antagonist flutamide also enhanced vasorelaxant action of ACh. When the male rat aorta was incubated in vitro with a nitric oxide (NO) synthase inhibitor L-NAME, phenylephrine-induced contraction was greatly potentiated in DHEA-pretreated rats compared to control ones. The present results suggest that DHEA stimulates mainly androgen in female, but both androgen and estrogen in male rats. The participation of NO In the modulation of vascular reactivity with pretreated DHEA was also considered.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.727-730
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• 2005

Cellulose based Electro-Active Papers (EAPap) is very promising material due to its merits in terms of large bending deformation, low actuation voltage, ultra-lightweight, and biodegradability. These advantages make it possible to utilize applications, such as artificial muscles and achieving flapping wings, micro-insect robots and smart wall papers. This paper investigates the in-plane strains of EAPap under electric fields, which are useful for a contractile actuator application The preparation of EAPap samples and the in-plane strain measurement system are explained, and the test results are shown in terms of electric field, frequency and the oriental ions of the samples. The power consumption and the strain energy of EAPap samples are discussed. Although there are still unknown facts in EAPap material, this in-plane strain may be useful for artificial muscle applications.

• Biomaterials and Biomechanics in Bioengineering
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• v.2 no.4
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• pp.225-235
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• 2015

Treatments for asthma are largely pharmaceutical, with some therapies also utilising alternative breathing techniques. The objective of both medical and alternative methods is to relax contracted airway smooth muscle (ASM). In normal subjects, tidal breathing- and deep inspiration-oscillations are believed to have a bronchodilatory effect. Similarly, application of length oscillations to isolated, contracted ASM also elicits muscle relaxation. As a means of investigating more-effective alternative treatment methods for contracted airways, we analyse the combined effects of bronchodilators and length oscillations on isolated, contracted ASM. The contractile state of the muscle tissue prior to treatment is of primary interest. Thereafter, the effect of applying a combination of small superimposed length oscillations with tidal breathing-like oscillations to ASM is studied alone and in combination with a common bronchodilator, isoproterenol (ISO). This work suggests that relaxation of isolated, contracted ASM following application of combined oscillations and ISO is larger than treatments of either combined oscillations or ISO alone. Further, the observed oscillation-associated relaxation is found to be amplitude- rather than frequency-dependent. This study gives additional insight into the role of oscillations and bronchodilators on contracted airways.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.4
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• pp.1036-1040
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• 2004

The purpose of the present study is to measure the effect of Tuber Pinelliae on EP(epinephrine) induced contraction of isolated rat thoracic aorta. Contractile force was measured with force displacement transducer under 1.5g loading tension. The mean percent increasing of rCBF was 11.4% (p<0.05) after 10㎎/㎏ Tuber Pinelliae. Contractions evoked by EP (ED50) and KCI 65.4mM were decreased significantly by Tuber Pinelliae. L-NNA, ODQ and atropine significantly altered the effect of Tuber Pinelliae, but propranolol and indomethacin did not change the relaxation of Tuber Pinelliae. These results indicate that Tuber Pinelliae can relax EP and KCI induced contraction of isolated rat thoracic aorta and that this decreasing contraction related to epithelium, nitric oxide, and parasympathetics.

• The Journal of Internal Korean Medicine
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• v.11 no.1
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• pp.165-177
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• 1990

In order to study the effects of HWA GAE SAN known clinically for their effects of treatment for cough and asthma, the study was carried out to investigate the effect of HWA GAE SAN extract on the contractile force of isolated guinea pig trachea smooth muscle and elucidate its mechanism. The results were obtained as follows. 1. Preparation of isolated guinea pig trachea smooth muscle was suspended in the oxygeneted Kreb's Henseleit bicarbonate buffer solution at $37^{\circ}C$ and recorded the developed tension by the drug with the isometric transducer (Nacro F-60). The restin tension was approximately 0.5g. 2. The trachea smooth muscle in normal state showed a significant atony to the increase of density of HWA GAE SAN. 3. The atonic effect of the trachea smooth muscle was restricted after prescription of Pyrilamine& Cyproheptadine. Hireceptor broker, which were prearranged. 4. After 5, 15, 50& $150{\mu}l/ml$ of HWA GAE SAN were prescribed, the atony of trachea smooth muscle was caused by Histamine. 5. After 50& $150{\mu}l/ml$ of HWA GAE SAN were prescribed, the atony of trachea smooth muscle was remarkably dwindled which was caused by Acetylcholine. 6. After $150{\mu}l/ml$ of HWA GAE SAN were prescribed, the atony of trachea smooth muscle was remarkably dwindled which was caused by 5-Hydroxytryptamine.

• The Korean Journal of Pharmacology
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• v.10 no.1 s.15
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• pp.47-52
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• 1974

The isolated rabbit gall bladder strips were prepared according to the technique described by Amer and Becvar (1969). The strips were placed in a bath containing 100 ml of Locke-Ringer solution maintained at $38^{\circ}C$. Oxygen was continuously bubbled through the solution. The tension of the muscle strip was initially adjusted to 0.7g. The contractile response was measured isometrically by a force-displacement transducer connected to a polygraph. The effect of a number of autonomic drugs were studied for their interaction with caerulein (Prof. V. Erspamer, F.I. 6934 Caerulein, Farmitalia, Italia), a gastrin or CCK.PZ like peptide, on isolated rabbit gall bladder strips. In this preparation caerulein produced contractions of CCK-PZ type, but the relative potency on a weight basis was 40 times that of CCK-PZ. The response of caerulein was not modified by either cholinergic or alpha or beta adrenergic blockade. However, the response of caerulein and of barium on the strips were prevented by papaverine or aminophylline. Isoproterenol, papaverine or aminophylline alone relaxed the preparation whereas caerulein, CCK-PZ, acetylcholine, serotonin, histamine or barium chloride contracted the preparation. In summary, it is concluded that caerulein on the gall bladder strip seems to act independently of the autonomic nervous system and mediated via mechanisms apparently similar to those involved in the action of barium chloride.

• Archives of Pharmacal Research
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• v.22 no.5
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• pp.479-484
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• 1999

In this study, the effects of ursodeoxycholic acid (UDCA) on ischemia/reperfusion injury were investigated on isolated heart perfusion model. Hearts were perfused with oxygenated Krebs-Henseleit solution (pH 7.4, $37^{\circ}C$) on a Langendroff apparatus. After equilibration, isolated hearts were treated with UDCA 20 to 160 $\mu$M or vehicle (0.04% DMSO) for 10 min before the onset of ischemia. After global ischemia (30 min), ischemic hearts were reperfused and allowed to recover for 30 min. The physiological (i.e. heart rate, left ventricular developed pressure, coronary flow, double product and time to contracture formation) and biochemical (lactate dehydrogenase; LDH) parameters were evaluated. In vehicle-treated group, time to contracture formation was 21.4 min during ischemia, LVDP was 18.5 mmHg at the endpoint or reperfusion and LDH activity in total reperfusion effluent was 54.0 U/L. Cardioprotective effects of UDCA against ischemia/reperfusion consisted of a reduced TTC $(EC_{25}=97.3{\mu}M)$, reduced LDH release and enhanced recovery of cardiac contractile function during reperfusion. Especially, the treatments of UDCA 80 and $160 {\mu}M $ significantly increased LVDP and reduced LDH release. Our findings suggest that UDCA ameliorates ischemia/reperfusion-induced myocardial damage.

• The Korean Journal of Pharmacology
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• v.16 no.1 s.26
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• pp.57-63
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• 1980

The Pharmacologic action of ethanol extracts and essential substance obtained from fruits of Evodia rutaecarpa are studied. 1) Motility of the isolated rabbit-intestine was decreased in proportion to the concentration of essential substance. 2) Intestinal contraction induced by acetylcholine 10? 6g/ml was inhibited by the essential substance $10^{-5}g/ml$. 3) Contractile responses of the isolated rabbit-intestine by serotonin $10^{-5}g/ml$ and histamine $10^{-5}g/ml$ were depressed significantly with the essential substance $10^{-5}g/ml$. 4) Alpha adrenergic receptor blocking effect of dihydroergotamine was interfered significantly with the essential substance. 5) Analgesic effect in mice by acetic acid stimulating method was observed significantly with both of the ethanol extracts and essential substance. 6) Blood pressure and respiration of the rabbits were not significantly influenced with the essential substance.

• The Korean Journal of Pharmacology
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• v.11 no.2
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• pp.9-17
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• 1975

The adrenergic blocking activity and refractory period of cardiac muscle on isolated rabbit atria were measured after administration of Scutellaria. In rabbits and cats the antiarrhythmic action of Scutellaria on atrial and ventricular arrhythmias produced by epinephrine or ouabain was examined and also compared with that of propranolol and quinidine. The alcoholic extract of Scutellaria produced a marked decrease in heart rate and contractile amplitude of the isolated rabbit atria. Pretreatment with Scutellaria rendered the atria to fail to respond to epinephrine, indicating that this crude drug possesses an adrenergic blocking activity. The extract produced a marked prolongation of the refractory period of atrial muscle. The extract effectively abolished the spontaneous arrhythmia occurring in the isolated rabbit atria. As propranolol and quinidine it also suppressed the atrial arrhythmia induced by ouabain. The extract prevented, as propranolol and quinidine, the induction of ventricular arrhythmia arising from excessive dose of epinephrine in anesthetized rabbits and cats. With regard to the ventricular arrhythmia induced by a continuous infusion of ouabain, the alcoholic extract of Scutellaria exerted some suppressive effect in anesthetized rabbits but no effect on cats. From the above results, it may be concluded that Scutellaria is effective against atrial and ventricular arrhythmias. The antiarrhythmic effects of this drug may be the result of adrenergic beta receptor blocking and cardiac depressive activities including prolongation of the refractory period of cardiac muscle.

• Korean Journal of Acupuncture
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• v.17 no.1
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• pp.75-80
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• 2000

Fructus Aristolochiae has been used in Korea for many centuries as a treatment for various disease.The purpose of the present study is to determine the effect of Fructus Aristolochiae on norepinephrine(NE) induced blood vessel contraction in rabbits. Rabbit(2 kg, male) were killed by $CO_2$ exposure and a segment (8-10mm) of each rabbit was cut into equal segments and mounted in a tissue bath. Contractile force was measured with force displacement transducers under 2-3 g loading tension. The dose of norepinephrine(NE) which evoked 50% of maximal response ($ED_{50}$) was obtained from cumulative dose response curves for NE ($10^{-6}{\sim}10^{-3}M$). Contractions evoked by NE ($ED_{50}$) were inhibited significantly by Fructus Aristolochiae in abdominal aorta and femoral artery. Fructus Aristolochiae inhibited the relaxation pretreated propranolol and L-NNA in femoral artery. But Fructus Aristolochiae did not effect the relaxation pretreated ODQ in femoral artery and abdominal aorta. These results indicate that Fructus Aristolochiae can relax NE induced contraction of rabbit blood vessel selectively, and that this relaxation relates to nitric oxide synthesis and sympathetic action.