• Title/Summary/Keyword: agonist-contraction

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Ginsenosides Evoke Vasorelaxation in Rat Aortic Rings: Involvement of $Ca^{2+}$-dependent $K^+$ Channels

  • Nak Doo Kim;Soo
    • Proceedings of the Ginseng society Conference
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    • 1998.06a
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    • pp.182-189
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    • 1998
  • Administration of ginsenosides, a mixture of saponin extracted from Panax ginseng, decreased blood pressure in rat. Previous studies have shown that ginsenosides caused endothelium-dependent relaxation, which was associated with the formation of cyclic GMP, suggested that ginsenosides caused release of nitric oxide (NO) from the vascular endothelium. The aim of the present study was to characterize the endothelium-independent relaxation to ginsenosides in the isolated rat aorta. Ginsenosides caused a concentration-dependent relaxation of rat aortic rings without endothelium constricted with 25 mM KCI but affected only minimally those constricted with 60 mM KCI. Ginsenoside Rg3 (Rg3) was a more potent vasorelaxing agonist than total ginsenoside mixture and also the ginsenoside PPT and PPD groups. Relaxation to ginsenosides were markedly reduced by TEA, but not by glibenclamide. Rg3 significantly inhibited Cal'-induced concentration-contraction curves and the "50a2'influx in aortic rings incubated in 25 mM KCI whereas those responses were not affected in 60 mM KCI. Rg3 caused efflux of $"Rb in aortic rings that was inhibited by tetraethy- lammonium (TEA), an inhibitor of Ca"-dependent K'channels, but not by glibenclamide, an inhibitor of AfP-dependent K'channels. These findings indicate that ginsenosides may induce vasorelaxation via activation of Ca2'-dependent K'channels resulting in hyperpolarization of the vas- cular smooth muscle with subsequent inhibition of the opening of voltage-dependent Caf'channels. These effects could contribute to explain the red ginseng-associated vasodilation and the beneficial effect on the cardiovascular system.

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Literature review of PNF application for improvement of fitness in the elderly (노인의 기초 체력 향상을 위한 PNF 기법 적용)

  • Han, Jin-Tae;Bae, Sung-soo
    • PNF and Movement
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    • v.6 no.1
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    • pp.27-32
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    • 2008
  • Purpose : The purpose of this study is to review of effect of the PNF application for improvement of the basic physical fitness in the elderly. Methods : By using internet, we research the PubMed, Science Direct, KISS, DBpia and the article on the effect of PNF. We selected the article between 1970 and 2007. Key words were PNF, Exercise, Elderly. Results : PNF refers to any of several post-isometric relaxation stretching techniques in which a muscle group is passively stretched, then contracts isometrically against resistance while in the stretched position, and then is passively stretched again through the resulting increased range of motion. Most PNF techniques employ isometric agonist contraction/relaxation where the stretched muscles are contracted isometrically and then relaxed. The most common PNF techniques are CR, HR, CRAC, HR-AC, AC. PNF exercise effected on the muscular strength and flexibility and balance and ROM in the elderly. Conclusion : PNF is a safety and effective exercise to improve the muscular strength and flexibility and balance and ROM in the elderly. Therefore, we suggest that PNF need to generalize for the elderly.

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Review of characteristics of the isotonic combination: Importance of eccentric training (등장성 수축 결합기법의 특성에 대한 고찰 - 원심성 훈련의 중요성 -)

  • Kim, Mi-hyun;Bae, Sung-soo
    • PNF and Movement
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    • v.2 no.1
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    • pp.25-33
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    • 2004
  • Purpose : The purpose of this article is to summarize the characteristics of isotonic combination. Method : Some studies of the motor unit activation patterns during isometric, concentric, and eccentric actions, neural strategies in the control of muscle force, and concentric versus combined concentric-eccentric training were reviewed. Results & Conclusions : Eccentric torque may be relatively higher than concentric torque for two potential reasons: 1) stretch responses in the antagonist are not elicited to restrain the motion as can occur concentrically and 2) stretch responses in the agonist may augment eccentric torque production. Concentric-eccentric training has a greater influence on functional capacity than that of concentric training. Both maximal force and average force throughout the motion were significantly higher when the dynamic action was started with preactivation as compared to the mode without preactivation. The peak torques observed during the concentric phase of the eccentric-concentric muscle actions were higher than those noted in the pure concentric contraction.

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Melatonin inhibits nicotinic acetylcholine receptor functions in bovine chromaffin cells

  • Jo, Su-Hyun;Lee, Seung-Hyun;Kim, Kyong-Tai;Choi, Se-Young
    • International Journal of Oral Biology
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    • v.44 no.2
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    • pp.50-54
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    • 2019
  • Melatonin is a neurotransmitter that modulates various physiological phenomena including regulation and maintenance of the circadian rhythm. Nicotinic acetylcholine receptors (nAChRs) play an important role in oral functions including orofacial muscle contraction, salivary secretion, and tooth development. However, knowledge regarding physiological crosstalk between melatonin and nAChRs is limited. In the present study, the melatonin-mediated modulation of nAChR functions using bovine adrenal chromaffin cells, a representative model for the study of nAChRs, was investigated. Melatonin inhibited the nicotinic agonist dimethylphenylpiperazinium (DMPP) iodide-induced cytosolic free $Ca^{2+}$ concentration ($[Ca^{2+}]_i$) increase and norepinephrine secretion in a concentration-dependent manner. The inhibitory effect of melatonin on the DMPP-induced $[Ca^{2+}]_i$ increase was observed when the melatonin treatment was performed simultaneously with DMPP. The results indicate that melatonin inhibits nAChR functions in both peripheral and central nervous systems.

Characterization of the drug receptors responsible for intestinal contraction in Israeli carp (이스라엘잉어 장관 수축에 관여하는 약물수용체에 관한 연구)

  • Yun, Hyo-in;Han, Kyong-oh;Park, Seung-chun;Cho, Joon-hyoung;Oh, Tae-kwang
    • Korean Journal of Veterinary Research
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    • v.34 no.3
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    • pp.447-456
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    • 1994
  • In order to elucidate the characterization of receptors involved in inestinal motility of Israeli carp, spontaneously contracting Israeli carp intestinal preperations were prepared and mounted in the organ chambers for contraction traicings using a polygraph. Various contractile agonists were treated and their dose-response curves were constructed. $EC_{50}$ values$(pD_2)$ of each agonist on specific receptors, $pA_2$ values of competitive antagonists against some agonists, and $K_1$, values of noncompetitive antagonists against some agonists were analyzed for characterization of receptors related with the intestinal contraction. Results obtained through the experiments were summarized as follows: 1. Acetylcholine(ACh) exhibited biphasic dose-response curves: initial ACh-induced dose dependent contractions were observed in pM levels but followed by decreased response in in-between concentration levels. Dose dependent contractions reappeared in ${\mu}M$ level. The peaks in pM and ${\mu}M$ levels appeared in $10^{-13}M$ and $3{\times}10^{-5}M$, respectvely. 2. Carbachol(CaCh) exhibited dose dependent contractions from $10^{-9}M$ to $10^{-5}M$, and its $pD_2$ values were higher than those of ACh($5.60{\pm}0.11$). ACh and CaCh exhibited equiactive contractions. Nicotine had no effects on contractile responses of Israeli carp intestine. 3. ACh-induced responses were inhibited by atropine($K_1:7{\times}10^{-8}M$), a muscarinic antagonist, in a non-competitive manner. But CaCh-induced responses were inhibited by both antimuscarinic atropine($pA_2:9.52{\pm}0.14$) and selective $M_2$ antagonistic 4-DAMP($pA_2:8.16{\pm}0.09$), in competitive manners. Nicotine receptor antagonistic decamethonium and hexamethonium had no effects on ACh-and CaCh-induced contractions. Therefore, the cholinergic receptor related to intestinal motility of Israeli carp was assumed as $M_2$ type. 4. In Israeli carp intestine, 5-HT (serotonin) exhibited dose dependent contractions in concentration range from $10^{-8}M$ to $10^{-5}M$. The maximal responses, however, were corresponded to about 50% of those of ACh or CaCh. 5-HT induced contractions were inhibited by $5-HT_2$ antagonistic ketanserin ($K_1: 7.8{\times}10^{-4}M$) in a non-competitive manner, but not by both of anti $5-HT_1$, spiperone and anti $5-HT_3$, MDL-72222. Hence, $5-HT_2$ receptors are suggested to be existed in Isreli carp intestine.

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Actions of acetylcholine, norepinephrine, histamine and prostaglandin F2α on motility of pig oviductal isthmic smooth muscle (돼지 난관협부 평활근의 운동성에 대한 acetylcholine, norepinephrine, histamine 및 prostaglandin F2α의 작용)

  • Rho, Gyu-jin;Park, Sang-eun;Shim, Cheol-soo;Kim, Joo-heon;Choe, Sang-young
    • Korean Journal of Veterinary Research
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    • v.34 no.3
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    • pp.493-500
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    • 1994
  • The purpose of this study was to investigate the effects of neurotransmitters and the source of $Ca^{2+}$ in the effects of neurotransmitters on the motility of pig oviductal isthmic smooth muscle. The motility of the isolated smooth muscle was recorded by using physiological recording system. The results were summarized as follows; Acetylcholine, norepinephrine, histamine and prostaglandin $F_{2{\alpha}}(PGF_{2{\alpha}})$ caused the contraction and the contractile responses were increased in a dose-dependent manner from the concentration of $10^{-7}$ to $10^{-4}M$. The maximum contractility of acetylcholine, norepinephrine, histamine and $PGF_{2{\alpha}}$ was 65.99, 28.66, 83.99 and 47.33% of 100 mM K contraction, respectively. The contractile response induced by acetylcholine$(10^{-6}M)$ was completely blocked by the pretreatment with cholinergic receptor blocker, atropine$(10^{-6}M)$, the contractile response induced by norepinephrine$(10^{-5}M)$ was blocked by the pretreatment with ${\alpha}$-adrenergic receptor blocker, phentolamine$(10^{-6}M)$ but was not blocked and rather increased by the pretreatment with ${\beta}$-adrenergic receptor blocker. propranolol$(10^{-6}M)$, the contractile response induced by histamine$(10^{-6}M)$ was completely blocked by the pretreatment with $H_1$-histaminergic receptor blocker, pyrilamine$(10^{-6}M)$ but was increased by the pretreatment with $H_2$-histaminergic receptor blocker, cimetidine$(10^{-6}M)$. The contractile response induced by acetylcholine$(10^{-6}M)$, norepinephrine$(10^{-5}M)$ and histamine$(10^{-6}M)$ was weakly contracted response in $Ca^{2+}$-free medium, but the contractile response induced by $PGF_{2{\alpha}}(10^{-6}M)$ was disappeared. The contractile response induced by acetylcholine$(10^{-6}M)$, norepinephrine$(10^{-5}M)$ and histamine$(10^{-6}M)$ was powerfully depressed by the pretreatment with $Ca^{2+}$-channel blocker, verapamil$(10^{-5}M)$ but the contractile response induced by $PGF_{2{\alpha}}(10^{-6}M)$ was completely inhibited.

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EMG Signal Analysis of Upper Extremity Motor Function using Balance-handle Device (밸런스 핸들 장치를 이용한 상지 운동 기능의 근전도 신호 분석)

  • Lee, Choong-Keun;Song, Ki-Ho;An, Jae-Yong;Shin, Sung-Wook;Chung, Sung-Taek
    • Journal of rehabilitation welfare engineering & assistive technology
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    • v.10 no.4
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    • pp.295-303
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    • 2016
  • Rehabilitation of upper limb motor function of hemiplegic patient must maintain interest and demand a device for a quantitative evaluation of rehabilitation training. In this paper, we developed the device that is composed of arm cradle, handle, and balance ball for rehabilitation exercise. We have performed experiment for validity as to whether to use the rehabilitation device when tilting the upper extremity training device developed to measure changes in the EMG signal to the main upper limb muscles for 7 healthy volunteers. We have analyzed muscle activation signals on agonist and antagonist as a reference in the muscle contraction and relaxation in the upper limb extension and flexion when the balance-handle device is tilted to front-rear and left-right. The experimental results showed that a tendency of muscle activation of biceps, triceps, and deltoid used in upper limb motor function of hemiplegic patients from extension and flexion evaluation items of Fugl-Meyer Assessment(FMA). These results may be helpful for rehabilitation training for upper limb motor function of hemiplegic patients by utilizing a developed unit.

Chronic Cadmium Administration Preferentially Affects the Responsiveness Mediated by Pre- and Post-synatic ${\alpha}_2$-Adrenoceptors (카드미늄의 만성적 투여가 신경접합 전.후 ${\alpha}_2$-아드레날인 수용체에 의한 반응에 미치는 영향)

  • Hong, Ki-Whan;Rhim, Byung-Yong;Sohn, Uy-Dong
    • The Korean Journal of Pharmacology
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    • v.21 no.1
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    • pp.27-33
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    • 1985
  • Either the contraction of isolated was deferens or the increase of heart rate in the pithed rats induced by electrical stimulation was significantly augmented by cadmium administration (10 ${\mu}mols$ of cadmium acetate every other day for 2 weeks i.p.). These stimulation-induced responses were diminished by ${\alpha}_2$-adrenoceptor agonist, clonidine, and the inhibition was antagonized by yohimbine. Furthermore, the increase in diastolic blood pressure by clonidine was also significantly reduced after cadmium administration, whereas that by methoxamine was not influenced with this dose range of cadmium. With these results it may be postulated that the long-term cadmium exposure may preferentially affect the responsiveness of the presynaptic as well as the postsynaptic ${\alpha}_2$-adrenoceptors.

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Effects of frequency - amplitude electrical stimulation on sympathetic neurotransmitter and vasoactive intestinal peptide (SSP 주파수 진폭변조가 Vasoactive Intestinal Peptide와 $\beta$-endorphin, cGMP에 미치는 영향)

  • Choi Young-duk;Shim Kyu-Rhee;Chang Moon-kyung
    • The Journal of Korean Physical Therapy
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    • v.14 no.4
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    • pp.454-474
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    • 2002
  • Vasoactive intestinal peptide (VIP) is a very potent dilatator and a nonadrenergic, noncholinergic (NANC) neurotransmitter or neuromodulator in the peripheral and the central nervous systems. The mechanisms of action of VIP were examined in aortic circular and in uterine longitudinal smooth muscle strips of the rat. The effects of sympathetic neurotransmitter were investigated in gastric and aortic circular muscle strips of the mouse and the rat. The effects of silver spike point, SSP, low frequency electrical stimulations of VIP, sympathetic neurotransmitter and $\beta$-endorphin were examined in plasma, serum and 24h urine from the healthy volunteer. In gastric smooth muscle strips from the mouse, adrenergic neurotransmitter norepinephrine was inhibitory effected, followed by caused phasic and tonic contraction to the, muscrine receptor agonist carbachol and acetylcholine, respectively. In urine from the healthy volunteer, both norepinephrine and epinephrine were significantly decreased in continue type and low frequency (3 Hz) of SSP electrical stimulations. The contractile responses to S-HT in uterine longitudinal smooth muscle strips of the rats were completely decreased by a VIP 1 $\mu$M. The contractile responses to PGF2$\alpha$ were not decreased by a VIP. In plasma and serum from the healthy volunteer, both VIP and $\beta$-endorphin were significantly increased in continue type and low frequency (3 Hz) of SSP electrical stimulations. Therefore, this study demonstrate that VIP has the capacity to relax vascular or gastric smooth muscles in part by stimulating the generation of NO, and silver spike point low frequency electrical stimulation has the capacity both to decrease sympathetic neurotransmitters and to increase VIP, $\beta$-endorphin.

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Therapeutic Effects of Panax ginseng on the Neurotoxicity Induced by Abuse Drugs

  • Oh Ki-Wan
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 2005.11a
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    • pp.49-66
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    • 2005
  • Panax ginseng has been useful for the treatment of diverse disease in oriental countries for thousands of years. In addition, a folk medicine prescribed by seven herbal drugs including Panax ginseng has been antinarcotics in the treatment of morphine-dependent patients. Many articles have been reported on these works. Therefore, we review the protective effects of Panax ginseng on the neurotoxicity induced by abuse drugs. Ginseng total saponins (GTS) extracted and isolated by Panax ginseng antagonized Morphine-induced analgesia, and inhibited the development of analgesic tolerance to and physical dependence on morphine. GTS inhibited morphine-6 dehydrogenase, which catalyzes production of mophinone from morphine, and increased hepatic glutathione level responsible to toxicity. Therefore, we hypothesized that these dual actions of ginseng can be associated with the detoxication of morphine. In addition, the inhibitory or facilitated effects of GTS on electrically evoked contraction in guinea pig ileum ($\mu$-receptors) and mouse vas deferens($\delta$-receptors) were not mediated through opioid receptors, suggesting non-opioid mechanisms. On the hand, antagonism of U-50,488H ($\kappa$-agonist)-induced antinociception is mediated by serotonergic mechanisms. GTS also inhibited hyperactivity, reverse tolerance (sensitization) and conditioned place preference-induced by psychostimulants such as methamphetamine, cocaine and morphine. On the other hand, GTS reduced the dopamine levels induced by methamphetamine. Moreover, GTS blocked the development of dopamine receptor activation, showing antidopaminergic effect. We suggest that GTS Prevent the methamphetamine-induced striatal dopaminergic neurotoxicity. In addition, Ginsenoside also attenuates morphine-induced cAMP signaling pathway. These results suggested that GTS might be useful for the therapy of the adverse actions of drugs with abuse liability.

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