• Korean Journal of Fisheries and Aquatic Sciences
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• v.30 no.2
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• pp.244-251
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• 1997

The relationship between structure and biological activity was studied on the three neuropeptides (mammalian, trout- and goldfish-neuropeptide $\gamma$) that were syntheized by the solid-phase method. Circular dichroism spectra showed that mammalian, trout- and goldfish-neuropeptide $\gamma$ adopted an unordered structure in buffer solution. In the-presence of neutral and acidic liposomes, mammalian and trout-neuropeptioe $\gamma$ also took a random structure. However, goldfish-neuropeptide $\gamma$ took an $\alpha-helical$ structure in acidic liposomes. The intestinal motility response was investigated with carp intestines, guinea-pig ileums and rat duodenums. In case of carp intestine, contractile activity was as follows : goldfish-neuropeptide $\gamma\simeq$ trout-neuropeptide $\gamma>$ mammalian-neuropeptide $\gamma$, On the other hand, the contractile activity of mammalian-neuropeptide $\gamma$ was more potent than trout- and goldfish-neuropeptide $\gamma$ in the guinea-pig ileums and rat duodenums. These results suggest that neuropeptide $\gamma$ show the species-specific activity.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.10
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• pp.2997-3003
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• 2009

The pharmacological profile of KR-31081, a nonpeptide $AT_1$ selective angiotensin receptor antagonist, was investigated by receptor binding studies, functional in vitro assays with rabbit aorta. KR-31081 inhibited the specific binding of $[^{125}I]\;[Sar^1,\;Ile^8]$-angiotensin II to human recombinant $AT_1$ receptor with an 8.6-fold greater potency than losartan ($IC_{50}$: 1.43 and 12.3 nM, respectively), but it did not inhibit the binding of [$^{125}I$] CGP 42112A to human recombinant $AT_2$ receptor ($IC_{50}$: higher than $10{\mu}M$ for both). The Hill coefficient for the competition curve of KR-31081 against $AT_1$ receptor was not significantly different from unity (0.99). Scatchard analysis showed that KR-31081 interacted with human recombinant $AT_1$ receptor in a competitive manner, as with losartan. In functional studies with rabbit aorta, KR-31081 competitively inhibited the contractile response to angiotensin II ($pK_B$ values: 8.66) with 20-70% decrease in the maximum contractile responses, unlike losartan that showed competitive antagonism without any change in the maximum contractile responses to angiotensin II ($pA_2$ values: 7.59). These results suggest that KR-31081 is a highly potent $AT_1$ selective angiotensin II receptor antagonist with a mode of insurmountable antagonism to be developed as the exploratory potential of this compound.

• The Korea Journal of Herbology
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• v.23 no.4
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• pp.135-147
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• 2008

Objectives: Oriental pear was used as traditional remedies for respiratory diseases like cough and asthma etc. The purpose of this study was to observe the effects of preventing asthma by the combination of phenolic compound extracted from pear and herbal drugs. Methods: In order to study the effects of preventing asthma by the combination of phenolic compound extracted from pear and herbal drugs(Platycodon grandiflorum, Prunus armeniaca) on allergic asthma, mice were pre-treated by oral administration of the solution before antigen sensitization for 10 days and 20days. And 2 days later, mice were actively sensitized with a subcutaneous injection of ovalbumin and 13 days later, they were provoked with ovalbumin aerosols. The experimental groups were divided 6groups(10d1P, 10d2P, 10d4P, 20d1P, 20d2P and 20d4P) by meditation quantity and period. We measured isometric contractile responses to acetylcholine(ACh) and KCl in the isolated tracheal smooth muscle(TSM), IL-4, eosinophil and lymphocyte in bronchoalveolar lavage fluid(BALF), IgE in serum, WBC, RBC and hemoglobin in blood. Results: Contractile responses of TSM to ACh, the sensitivity of TSM to Ach and the maximal contractile response of TSM to KCl were decreased by direct proportion of meditation quantity. Eosinophil and IL-4 level in BALF were more significantly decreased, and IgE level in serum was more significantly increased in 10d4P and 20d4P group than the control group. Conclusions: Based on the above results, it is assumed that oral administration of the combination of phenolic compound extracted from pear and herbal drugs(Platycodon grandiflorum, Prunus armeniaca) can help the preventing effects of allergic asthma.

• The Korean Journal of Physiology and Pharmacology
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• v.11 no.5
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• pp.175-182
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• 2007

Members of prostaglandin(PG) E-series elicit cellular effects mainly through adenylyl cyclase-cAMP signaling. The role of $PGE_2$-induced increase in cAMP has been shown to be compartmentalized in the cardiac myocytes: $PGE_2$-induced increase of cAMP is not involved in the control of cardiomyocytic contraction. The purpose of the present study was to define the effect of $PGE_1$ on the cGMP levels and the role of $PGE_1$ in the atrial secretory function. Experiments were performed in perfused beating rabbit atria and atrial contractile responses, cGMP and cAMP efflux, and atrial natriuretic peptide(ANP) secretion were measured. $PGE_1$ increased cGMP as well as cAMP efflux concentration in a concentration-dependent manner, however, no significant changes in atrial secretory responses were observed(with $1.0{\mu}M\;PGE_1$; for cGMP, $144.76{\pm}37.5%$, n=11 versus $-16.81{\pm}4.76%$, n=6, control, p<0.01; for cAMP, $187.60{\pm}41.52%$, n=11 versus $7.38{\pm}19.44%$, n=6, control, p<0.01). $PGE_1$ decreased atrial dynamics slightly but transiently, whereas $PGE_2$ showed similar effects but with lower potency. Isoproterenol increased atrial cAMP efflux(with 2.0 nM; $145.71{\pm}41.89$, n=5 versus $7.38{\pm}19.44%$, n=6, control, p<0.05) and mechanical dynamics and decreased ANP secretion. The $PGE_1$-induced increase in cGMP efflux showed a bell-shaped concentration-response curve. $PGE_1$-induced increase of cGMP efflux was not observed in the presence of L-NAME, an inhibitor of nitric oxide(NO) synthase, or ODQ, an inhibitor of NO-sensitive guanylyl cyclase. L-NAME and ODQ showed no significant effect on the $PGE_1$-induced transient decrease of atrial dynamics. These data indicate that $PGE_1$ increases cGMP levels via NO-soluble GC signaling in the cardiac atrium and also show that $PGE_1$-induced increases in cGMP and cAMP levels are not involved in the regulation of atrial secretory and contractile functions.

• Journal of Korean Physical Therapy Science
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• v.7 no.2
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• pp.567-577
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• 2000

In human body, catecholamines, such as epinephrine and norepinephrine, can be increased anxiety, blood pressure and pain etc. The inhibitory effects of TENS, electroacupuncture and massage on the release of epinephrine, norepinephrine from sympathetic nerve endings has already been known. However, the effects of silver spike point stimulation on the catecholamines was not well understood. Therefore, the purpose of this study was to characterize the SSP-induced inhibitory effects of catecholamines. The following results were obtained. (1) The studies on urinary catecholamines released that the levels of epinephrine and norepinephrine of continue type SSP stimulation group were significantly lower than those in the control group in human in vivo. (2) The dose-response curves of epinephrine and norepinephrine in rat aortic smooth muscle strips were increased dose dependent manner respectively. However, the contractile response of norepinephrine in rat aortic smooth muscle strips were slightly differentiated. It is concluded that the SSP stimulation reflects to the inhibitory effects of epinephrine and norepinephrine in men. Especially, we believe that the amplitude-frequency modulation, such as continue type a)1d frequency modulation type, of SSP stimulation plays a role in regulating catecholamines.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.1
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• pp.83-90
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• 2017

Advanced age is one of the risk factors for vascular diseases that are mainly caused by impaired nitric oxide (NO) production. It has been demonstrated that endothelial arginase constrains the activity of endothelial nitric oxide synthase (eNOS) and limits NO generation. Hence, arginase inhibition is suggested to be vasoprotective in aging. In this study, we examined the effects of intravenous injection of Piceatannol, an arginase inhibitor, on aged mice. Our results show that Piceatannol administration reduced the blood pressure in aged mice by inhibiting arginase activity, which was associated with NO production and reactive oxygen species generation. In addition, Piceatannol administration recovered $Ca^{2+}$/calmodulin-dependent protein kinase II phosphorylation, eNOS phosphorylation and eNOS dimer stability in the aged mice. The improved NO signaling was shown to be effective in attenuating the phenylephrine-dependent contractile response and in enhancing the acetylcholine-dependent vasorelaxation response in aortic rings from the aged mice. These data suggest Piceatannol as a potential treatment for vascular disease.

• The korean journal of orthodontics
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• v.42 no.2
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• pp.64-72
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• 2012

Objective: The aims of this study were to examine whether a passive stretch stimulus by means of a functional appliance induces changes in the fiber composition of masticatory muscles and whether these changes are similar to the changes in stretched limb muscle fibers by using RT-PCR, western blot, and immunohistochemical assays. Methods: Five male New Zealand White rabbits were fitted with a prefabricated inclined plane on the maxillary central incisors to force the mandible forward (- 2 mm) and downward (- 4 mm). Further, 1 hind limb was extended and constrained with a cast so that the extensor digitorum longus (EDL) was stretched when the animal used the limb. The animals were sacrificed aft er 1 week and the masseter, lateral pterygoid, and EDL were processed and compared with those from control animals (n = 3). Results: The stretched EDL had a significantly higher percentage of slow fibers, whereas the stretched masticatory muscles did not show changes in the composition of the major contractile proteins aft er 7 days. Conclusions: The transition of fiber phenotypes in response to a stretch stimulus may take longer in the masticatory muscles than in the limb muscles.

• 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.

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

• The Korean Journal of Pharmacology
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• v.24 no.2
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• pp.203-216
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• 1988

To delineate the mechanisms of vasoconstriction and vasodilation in cerebral arteries the effects of some vasoconstrictors and calcium antagonists on the basilar artery (BA) and arterial circle of Willis (WC) were examined and also the role of endothelium in the action of these drugs was investigated in pigs, cats and rabbits. In pig cerebral arteries, dose-dependent contractile responses were elicited by KCI, histamine, 5-hydroxytryptamine (5-HT) and angiotensin, but norepinephrine (NE), phenylephrine (PE) and epinephrine (EP) elicited dose-dependent contractions only under pretreatment with propranolol 10-6 M. The magnitudes of maximal contractile effects of these drugs were different from each other, and 5-H~ was the largest and angiotensin the smallest. Some calcium antagonists dose-dependently inhibited KCI (35 mM)-induced contraction and the order of potency in inhibiting the contraction was nifedipine > > diltiazem > flunarizine > oxybutynin > isosorbide dinitrate (ISDN) > glyceryl trinitrate. 5-HT (10-6 M)-induced contraction was dosedependently inhibited by nifedipine but slightly inhibited by diltiazem and ISDN. In rings with intact endothelium, KCI (35 mM)-induced contraction was not affected by acetylcholine (ACh) but $PGF_{2{\alpha}}$ (lO-SM)-induced contraction was dose-dependently relaxed by ACh and adenosine. This endothelium-dependent relaxation was not affected by nifedipine (l0-6M)-pretreatment but markedly inhibited by methylene blue (50,uM)-pretreatment. In the porcine arterial rings without endothelium, ACh had no effect or even contracted the $PGF_{2{\alpha}}-induced$ contraction. However, the dosedependent relaxing effect of ACh appeared when the deendothelized porcine ring and rabbit thoracic aorta with intact endotheli urn were simultaneously suspended into a bath and this relaxing effect was also inhibited by methylene blue-pretreatment. In cat cerebral arteries, 5-HT and NE elicited dose-dependent contractile responses and ACh also produced dose-dependent contraction regardless of the existence of endothelium. ACh-induced contraction was most prominent. 5-HT (IO-SM)induced contraction was not relaxed but contracted additionally by ACh even in the intact endothelial ring. In rabbit cerebral arteries, 5-HT and NE elicited dose-dependent contractile responses and 5-HT-induced contraction was more prominent. In the intact endothelial preparations, 5-HT (lO-s M)-induced contraction was markedly relaxed by the addition of ACh( IO-SM) and this endothelium-dependent relaxing effect was inhibited by atropine (l0-7M)-pretreatment but notaffected by diltiazem (l0-6M)-pretreatment. These results suggest that ACh elicits endotheliumdependent relaxing effect mediated by muscarinic receptors in cerebral arteries of pig and rabbit, and that ACh acts as vasoconstrictor in cat cerebral artery.