• Korean Journal of Veterinary Research
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• v.37 no.1
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• pp.119-128
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• 1997

The relaxation of gastric fundus smooth muscles is the primary physiological event which induces the receptive relaxation of monogastric animals. L-arginine/Nitric oxide(L-arg/NO) system is known to mediate the inhibitory non-adrenergic non-cholinergic(NANC) neurotransmission in various tissues including gastrointestinal smooth muscles. The longitudinal smooth muscles of porcine gastric fundus showed fast relaxation during electrical field stimulation(EFS) and rebound contraction after EFS in NANC condition. So, the purpose of present study was elucidation of the neurotrasmitters related to the NANC relaxation and explanation of the relation between NANC relaxation and L-arg/NO system. The longitdinal smooth muscles of porcine gastric fundus were hung in the organ bath and under the presence of guanethidine($5{\times}10^{-5}M$), precontraction was induced by carbachol($1{\times}10^{-6}M$). The muscle responses to EFS and drugs were isomerically recorded. The rusults were summarized as follows. 1. The longtudinal muscles of porcine gastric fundus showed frequency-dependent relaxation and rebound contraction to electrical field stimulaton(1ms, 8V, 1~16Hz, 20sec, EFS). These responses were blocked by tetrodotoxin($1{\times}10^{-6}M$). 2. The relaxation and rebound contraction of the longitudinal muscles of porcine gastric fundus to EFS were inhibited by L-NAME($2{\times}10^{-5}M$). The inhibitory effect of L-NAME was antagonized by L-arginine($1{\times}10^{-3}M$), but not by D-arginine($1{\times}10^{-3}M$). 3. Exogenous NO($NaNO_2$, $1{\times}10^{-5}{\sim}1{\times}10^{-4}M$, pH=2.0) caused concentration-dependent relaxation as EFS did. 4. Methylene Blue($2{\times}10^{-5}M$), a soluble guanylate cyclase inhibitor, inhibited the relaxation and rebound contraction of the longitudinal muscles of porcine gastric fundus induced by EFS, but N-ethlmaleimide, a adenylate cyclase inhibitor, did not. 5. 8-Br-cGMP($1{\times}10^{-6}{\sim}3{\times}10^{-6}M$), permeable cGMP analogue, induced dose-dependent relaxation. but 8-Br-cAMP($1{\times}10^{-6}{\sim}3{\times}10^{-6}M$), permeable cAMP analogue, did not. Both did not evoked rebound contraction. 6. ${\alpha}$-chymotrypsin did not affect the relaxation of the longitudinal muscles of porcine gastric fundus. 7. Reactive blue 2($1{\times}10^{-4}M$, 40min) siginificantly inhibited the rebound contraction induced by EFS and inhibited contraction caused by exogenous ATP($1{\times}10^{-4}{\sim}1{\times}10^{-3}M$). These results suggests that NANC relaxation of the longitudinal muscles of porcine gastric fundus mainly mediated by NO and the rebound contraction is related to NO and other neurotransmitters.

• Korean Journal of Oriental Medicine
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• v.2 no.1
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• pp.236-254
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• 1996

This study was carried out to investigate the tracheal muscle relaxation of water extracts of three kinds of Coptis rhizoma and also compare their effects with berberine and palmatine, which are the important alkaloid components of Coptis rhizoma, in isolated rat tracheal smooth muscle. As a result Coptis chinenis showed significant tracheal muscle relaxation on KCI-induced contraction and more markedly on carbachol-induced contraction in dose-dependent manner. Coptis japoinin exhibited also tracheal muscle relaxation on both contraction with slightly weaker activities than those of Coptis chinensts. The activities of the root hair of Coptis chinensis were the most weakest in three rhizomas. Berberine and palmatine had strong tracheal muscle relaxation, especially, on carbachol-induced contraction, however, their activities on KCI-induced contraction were weaker than that of Coptis chinenis. The inhibitory effects of three kinds of Coptis rhizoma on the contraction by KCI and carbachol were investigated to explain the process of their tracheal muscle relaxation. All rhizomas inhibited the contraction by both agents, among them, Coptis japonica showed the most significant effect, so indicating that the tracheal muscle relaxation of Coptis rhizoma may be concerned with the blocking of muscarine receptor and $Ca^{2+}$channel.

• Journal of Chest Surgery
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• v.24 no.7
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• pp.637-646
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• 1991

Effect of noradrenaline and endothelium on the high K+ or Ach-induced contraction were investigated in the pig myocardial coronary artery. The helical strip of isolated pig myocardial coronary artery was immersed in the Tris-buffered Tyrode`s solution equilibrated with 100% O2 at 37oC and its isometric tension was measured. High K+ and Ach-induced contraction were dose-dependent. By denuding the endothelium, dose-contraction curve of K+ was not shifted significantly to the left and upward, but that of Ach was shifted significantly to same direction 25 mM K+ - and Ach-induced contraction were relaxed by norepinephrine[NE]. NE-induced relaxation was blocked by the pretreatment of propranolol, which was known as b-adrenoceptor blocker. And, phenylephrine known as a-adrenoceptor agonist, and clonidine known as a-adrenoceptor agonist increased the 25mM K+ - induced contraction respectively. Denuding of endothelium did not show any significant effects on NE-induced relaxation and contraction increased by phenylephrine and clonidine. Tyramine increased 25mM K+ - induced contraction further. The contractile response by tyramine on the 25mM K+ - induced contraction was not blocked by the pretreatment of phentolamine, but was partially blocked by the pretreatment of atropine. From the above results, it is suggested that activation of a1-and a2-adrenoceptors induce the contraction, activation of b-adrenoceptors induce the relaxation, and NE-induced relaxation is mainly due to activation of b-adrenoceptors. Also it is suggested that denudation of endothelium did not influence NE-induced relaxation, but influence Ach-induced contraction in the pig myocardial coronary artery.

• Biomolecules & Therapeutics
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• v.8 no.2
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• pp.113-118
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• 2000

TEA, glibenclamide, L-NAME and SKF 525A-induced reversible contraction were investigated using acetylcholine, sodium nitroprusside (SNP) and pinacidil in rat abdominal and thoracic aorta. Acetylcho-line, SNP or pinacidil produced in a dose dependent manner relaxation on phenylephrine-induced contraction In rat aorta. TEA, SKF 525A, and L-NAME produced reversible contractions on acetylcholine-induced relaxation, but not on SNP- or pinacidil-induced relaxation. Glibenclamide significantly produced reversible con- traction on pinacidll-induced relaxation. The reversible effect of TEA on the acetylcholine-induced relaxation was reduced by SKF 525A. These results indicate that the acetylcholine-induced relaxation may be mediated by NO, cytochrome P$_{450}$-dependent epoxygenase pathway, or $Ca^{2+}$ activated $K^{+}$ channel, and the pinacidil-induced relaxation may be mediated by ATP-sensitive $K^{+}$ channel.annel.

• The Korean Journal of Physiology
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• v.30 no.2
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• pp.269-278
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• 1996

The mechanism of impaired endothelium-dependent relaxation in the aorta of one-kidney, one clip Goldblatt hypertensive (1K,1C-GBH) rats was investigated. 8 week-old Wistar-Kyoto (WKY) rats were made hypertensive by left renal artery stenosis with contralateral nephrectomy. Endothelium-dependent relaxation was significantly reduced in 1K,1C-GBH rats as compared with WKY rats. However, the relaxation by sodium nitroprusside in 1K,1C-GBH rats was not reduced as compared with WKY rats. The impairment of endothelium-dependent relaxation in 1K,1C-GBH rats was partially restored by the pretreatment of indomethacin or SQ29548. When the nitric oxide production was inhibited by L-nitroarginine methyl ester, acetylcholine (ACh) induced a endothelium-dependent contraction that was greater in 1K,1C-GBH rats than in WKY rats. Endothelium-dependent contraction by ACh was completely abolished by indomethacin or SQ29548. However, imidazole, tranylcypromine and superoxide dismutase did not affect the endothelium-dependent contraction in 1K,1C-GBH rats. These results suggest that impaired endothelium-dependent relaxation in the 1K,1C-GBH rats might be due to the simultaneous release of EDCF, and that prostaglandin B2 may be involved as a mediator of endothelium-dependent contraction.

• PNF and Movement
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• v.14 no.1
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• pp.59-65
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• 2016

Purpose: The purpose of this study was to review articles in order to establish optimal contraction intensity and duration in the performance of relaxation techniques for maximal increase in range of motion. Methods: The Cochrane, EBSCO, Embase, Medline, ProQuest, PubMed, ScienceDirect, and Scopus databases were used to search articles from 1990 to January 2016. The search terms were "contract relax," "hold relax," "muscle energy technique (MET)," and "proprioceptive neuromuscular facilitation (PNF) stretching." Only experimental human studies (randomized controlled trials) that compared the effects of varying intensity and duration of isometric contraction were included. Non-English language and unpublished studies were excluded. Results: A total of 2,156 articles were initially identified, with only five eventually meeting the inclusion and exclusion criteria. Three studies compared the effects of varying intensity in isometric contraction and two studies compared the effects of varying duration in isometric contraction with regard to range of motion (ROM). Two articles suggested that submaximal voluntary isometric contraction was more effective than maximum voluntary isometric contraction (MVIC) in the improvement of ROM. One article showed that a longer contraction time led to greater increases in ROM. Conclusion: Submaximal voluntary isometric contraction was recommended during contract-relax exercises in healthy people. Lack of evidence makes it difficult to suggest the optimal duration of isometric contraction during relaxation techniques. For future research, high-quality evidence will be needed to establish the optimal contraction intensity for maximum improvement of ROM.

• Korean Journal of Veterinary Research
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• v.14 no.2
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• pp.207-210
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• 1974

Pharmacological investigation was performed in chickens which were pretreated with reserpine. Transmural stimulations were given to the isolated jejunum of chickens and studied the responses and the effects of dibenamine, propranolol, atropine and tetrodotoxin on them. The results obtained were summerized as follows: 1. Three different patterns of response were obtained from the isolated jejunum of non-treated chickens after giving them transmural stimulation. The first pattern was contraction followed by relaxation, the second pattern was contraction only and the third pattern was relaxation only. 2. The transmural stimulation of the jejunum preparations evoked relaxation while the periarterial stimulation evoked contraction in the reserpinized chick. 3. The relaxation response to the transmural stimulation was not affected by the pretreatment with dibenamine, propranolol and atropine. 4. The relaxation response to the transmural stimulation was abolished by tetrodotoxin. The results obtained in these studies indicate that the relaxation response to the transmural stimulation is due to non-adrenergic inhibitory fibers.

• The Korean Journal of Physiology
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• v.4 no.1
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• pp.59-67
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• 1970

In recent observations on vestibular eye movements in mammals, reported by several different workers, it was indicated that the pattern of reflex eye movement from semicircular canal nerve stimulation in rabbits was different from that observed in the other species such as cats and dogs. Observing the different anatomical features of the extraocular muscles of rabbits, Kim ascribed the different pattern of eye movement of rabbits to the functional difference of inferior and superior oblique muscles from those of other species. Present experiment was carried out to elucidate a physiological mechanism underlying in such particular pattern of reflex eye movement in rabbits. An individual canal nerve was selectively stimulated, under a dissecting microscope, by a fine electrode induced into an ampulla through a hole provided on the wall of corresponding osseous canal, and responses of the extraocular muscles were checked by recording the isotonic changes of muscle length. Following results were obtained. 1. Direct stimulation of the superior or inferior oblique muscles Produced upward or downward movement of the eye turning toward medial side respectively. 2. Stimulation of the unilateral canal nerve Produced a marked contraction of a main contracting ocular muscle and simultaneous relaxation of an antagonistic muscle in both eyes. Less potent contraction of an additional ocular muscle was observed and it appeared to augment the function of the main contracting muscle in the ipsilateral eye. 3. Stimulation of superior semicircular canal nerve caused a primary contraction of superior rectus, synergic contraction of superior oblique and relaxation of inferior rectus in ipsilateral eye. Contraction of inferior oblique and relaxation of superior oblique were observed in the contralateral eye. 4. Stimulation of lateral semicircular canal nerve produced a primary contraction of medial rectus, synergic contraction of superior oblique and relaxation of lateral rectus in the ipsilateral eye. Contraction of lateral rectus and relaxation of medial rectus were observed in the contralateral eye. 5. Stimulation of inferior semicircular canal nerve produced a primary contraction of superior oblique, synergic contraction of superior rectus and relaxation of inferior oblique in the ipsilateral eye. Contraction of. inferior rectus and relaxation of superior rectus were observed in the contralateral eye. 6. Upon stimulation of individual canal nerve, the pattern of eye movement in rabbits is different from those of cats, however, the responses of the extraocular muscles appear to be similar in two species. Therefore, it is concluded that the different Pattern of eye movement in both species are not due to the possible difference of vestibule-ocular reflex pathways but to the functional difference of superior and inferior oblique muslces.

• The Journal of Korean Medicine
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• v.21 no.1
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• pp.77-83
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• 2000

This study investigated the effects of Siegesbeckia glabrescens, an antihypertensive remedy, on the contraction evoked by phenylephrine and KCl in isolated rat thoracic arata, and also analyzed antioxidative status in vitro. Siegesbeckia glabrescens revealed dose-dependent relaxation on phenylephrine(PE)/KCl-induced arterial contraction and more markedly on PE-induced contraction. Siegesbeckia glabrescens reduced malondialdehyde(MDA)levels, Phosphatidyl choline-liposome(PC-OOH) contents, linoleic acid-induced lipid peroxidation and exerted 1,1-diphenyl-2- picryl-hydrazyl(DPPH) radical scavenging effect, in vitro. These results indicated that Siegesbeckia glabrescens doesn't relaxe artery through a blocking α-adrenergic receptor and calcium channel mediated by voltage-operated calcium channel, and it s antioxidative effects may be involved in endothelium-dependent relaxation of arteries via vascular protective properites. (J Korean Oriental Med 2000;21(1):77-83)

• Korean Journal of Veterinary Research
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• v.35 no.2
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• pp.279-285
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• 1995

To characterize non-adrenergic non-cholinergic(NANC) nerve mediated contractile responses in circular smooth muscle of bovine reticular groove, we investigated NANC relaxation and contraction induced by electric field stimulation to enteric nerves. In the presence of atropine($1{\mu}M$) and guanethidine($50{\mu}M$), electric field stimulation at frequency of 1 to 16Hz(square pulses, 0.5ms duration, 70V) evoked clear-cut relaxations through stimulations. Transient 'rebound contraction' was occured when the stimulus was switched off. All of the responses (relaxation and rebound contraction) were dose-dependently blocked by Nw-nitro-$_{\small{L}}$-arginine methyl ester(L-NAME), an inhibitor of nitric oxide synthesis, and methylene blue, and inhibitor of soluble guanylate cyclase. Tetraethyl ammonium(TEA), a potassium channel blocker, did not block the NANC relaxations.