Norimoto Urakawa's research while affiliated with Nippon Veterinary and Life Science University and other places
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Publications (282)
Exposure to chronic hypoxic conditions causes various gastric diseases, including gastric ulcers. It has been suggested that gastric smooth muscle contraction is associated with aerobic metabolism. However, there are no reports on the association between gastric smooth muscle contraction and aerobic metabolism, and we have investigated this associa...
The present study was designed to clarify phosphodiesterase 9 (PDE9) expression in bovine tracheal smooth muscle tissue, and to elucidate that PDE9 may contribute to the regulation of airway relaxation. PDE9 mRNA expression was detected in bovine tracheal smooth muscle. Sodium nitroprusside (an NO donor) and BAY 73-6691 (a selective PDE9 inhibitor)...
![Fig. 2. Changes of imidazole induced increases in [Ca 2+ ] i level...](publication/321871949/figure/fig2/AS:603027719344128@1520784420330/Changes-of-imidazole-induced-increases-in-Ca-2-i-level-F340-F380-and-muscle_Q320.jpg)
The mechanism of imidazole-induced contraction on the bovine tracheal smooth muscle was investigated. Imidazole induced muscle contraction in a concentration-dependent manner on bovine, porcine and guinea-pig tracheas, but not in rat or mouse. In bovine tracheas, imidazole was cumulatively applied and induced muscle tension and increasesd intracell...
Chlorogenic acid (CGA) is a polyphenol found in coffee and medicinal herbs such as Lonicera japonica. In this study, the effect of CGA-induced relaxation on carbachol (CCh)-induced contraction of mouse urinary bladder was investigated. CGA (30-300 μg/ml) inhibited CCh- or U46619-induced contraction in a concentration-dependent manner. SQ22536 (aden...
Recent studies have shown that phloridzin, an inhibitor of sodium-glucose cotransporter (SGLT), strongly decreases high K(+)-induced contraction in phasic muscle, such as tenia coli, but slightly affects tonic muscle, such as trachea . In this study, we examined the inhibitory mechanism of phloridzin on high K(+)-induced muscle contraction in rat i...
Eyes are supplied O2 through the cornea and vessels of the retina and iris, which are tissues characterized by aerobic metabolism. Meanwhile, there are no reports on the association between iris sphincter contraction and aerobic metabolism. In this paper, we studied the aforementioned association. Eyes from adult pigs of either sex were obtained fr...
This study examined the mechanism of vasorelaxation induced by dimethyl sulfoxide (DMSO) in endothelium-intact and -denuded rat aorta. DMSO (0.1-3%) inhibited phenylephrine (PE, 1 μmol/l)-induced contraction in a dose-dependent manner. However, this relaxation was lower in the absence of the endothelium. Increase in DMSO-induced relaxation in the p...
To elucidate the dependence of aerobic energy metabolism and utilization of glucose in contraction of urinary bladder smooth muscle, we investigated the changes in the reduced pyridine nucleotide (PNred) fluorescence, representing glycolysis activity, and determined the phosphocreatine (PCr) and ATP contents of the porcine urinary bladder during co...
The effects of papaverine on carbachol (CCh)- and high K(+)- induced contraction in the bovine abomasum were investigated. Papaverine inhibited CCh (1 µM) - and KCl (65 mM)-induced contractions in a concentration-dependent manner. Forskolin or sodium nitroprusside inhibited CCh-induced contractions in a concentration-dependent manner in association...
The effects of various selective phosphodiesterase (PDE) inhibitors on carbachol (CCh)-induced contraction in the bovine abomasum were investigated. Various selective PDE inhibitors, vinpocetine (type 1), erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA, type 2), milrinone (type 3), Ro20-1724 (type 4), vardenafil (type 5), BRL-50481 (type 7) and BAY73-6...
To elucidate the role of glycogen in the contraction on tracheal smooth muscle, we investigated the changes in the glycogen contents of bovine trachea contraction induced by high K(+) and hypoxia (achieved by bubbling N(2) instead of O(2)), either in a glucose-free condition or in the presence of iodoacetic acid (IAA), an inhibitor of glycolysis. T...
Abstract— The mechanism of endothelium-dependent relaxation induced by pirarubicin, (2″R)-4′-O-tetrahydropyranyladriamycin, THP, or carbachol was investigated in the rat isolated aorta. The relaxant effect of THP (1·5 × 10−6-4·5 × 10−5m) or carbachol (10−8-10−4m) on the aorta with endothelium was decreased by lowering Ca2+ in the medium. The relaxa...
This study examined the inhibitory effects of papaverine on twitches directly elicited by electrical stimulation of the mouse diaphragm. Papaverine (3-100 μM) inhibited twitches in a dose-dependent manner. Papaverine increased the cyclic adenosine monophosphate (cAMP) but not cyclic guanosine monophosphate (cGMP) content. IBMX, Db-cAMP and 8-br-cGM...
![Fig. 4. Representative recordings showing the increase in [Ca 2+ ]i...](publication/43099997/figure/fig3/AS:11431281128234008@1679319656962/Representative-recordings-showing-the-increase-in-Ca-2-i-levels-F340-F380-upper_Q320.jpg)
The effects of various selective phosphodiesterase (PDE) inhibitors on muscle contractility and cyclic nucleotide content in the porcine coronary artery were investigated. Various selective PDE inhibitors, vinpocetine (type 1), erythro-9-(2-hydroxy-3-nonyl) adenine (EHNA, type 2), milrinone (type 3), rolipram (type 4), Ro20-1724 (type 4), and zapri...
The effects of various selective phosphodiesterase (PDE) inhibitors on muscle contractility and cyclic nucleotide contents in porcine iris sphincter were investigated. Forskolin and sodium nitroprusside inhibited carbachol (CCh)-induced contraction in a concentration-dependent manner. Various selective PDE inhibitors, vinpocetine (type 1), erythro...
![Fig. 2. Effects of I-154 K + solution on [Ca 2+ ] i level (F340/F380,...](publication/26868144/figure/fig2/AS:11431281124444894@1677948784417/Effects-of-I-154-K-solution-on-Ca-2-i-level-F340-F380-upper-trace-and-muscle_Q320.jpg)
A high-K(+), Na(+)-deficient (isosmotic 154 mM K(+) and 0 mM Na(+); I-154 K(+)) solution induced contraction followed by gradual relaxation of the smooth muscles of the porcine trachea, while hyperosmotic addition of 65 mM KCl (H-65 K(+)) induced a large sustained contraction. The I-154 K(+) solution also induced a sustained increase in [Ca(2+)](i)...
![Fig. 6. Effects of ibudilast (30 µM) on the increases in [Ca 2+ ]i...](publication/6172157/figure/fig5/AS:11431281119462342@1676084584100/Effects-of-ibudilast-30-M-on-the-increases-in-Ca-2-i-level-F340-F380-and-muscle_Q320.jpg)
The mechanism by which ibudilast induces vasodilation was examined in isolated endothelium-denuded rat aorta. Ibudilast inhibited the contractions induced by phenylephrine (PE) and high K(+) with decrease of [Ca(2+)](i) level in a concentration-dependent manner, to the same degree. 3-Isobutyl-1-methylxanthine (IBMX) inhibited PE-induced contraction...
A high-K+, Na+-deficient (I-154 K+) solution induced contraction followed by gradual relaxation of the smooth muscles of the bovine trachea, while hyperosmotic addition of 65 mM KCl induced a large sustained contraction. Exposure of the muscle to the I-154 K+ solution induced an increase in the ratio of cellular water content and a sustained increa...
In this study, we examined the inhibitory mechanism of monensin on high K+-induced contraction in guinea-pig urinary bladder. The relaxant effect of monensin (0.001 - 10 microM) was more potent than those of NaCN (100 microM - 1 mM) and forskolin (3 - 10 microM). Monensin (0.1 microM), NaCN (300 microM), or forskolin (10 microM) inhibited high K+-i...
We have demonstrated that the relaxing mechanism of papaverine in phasic muscles such as ileum, urinary bladder, and uterus is different from tonic muscles such as aorta. In this study, we examined the inhibitory mechanism of papaverine on carbachol (CCh)-induced contraction in the bovine trachea. Papaverine inhibited muscle contraction and increas...
The effects of various selective phosphodiesterase (PDE) inhibitors on muscle contractility and cyclic nucleotide contents in the guinea pig gall bladder were investigated. Various selective PDE inhibitors, vinpocetine (type 1), erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA, type 2), milrinone (type 3), Ro20-1724 (type 4), and zaprinast (type 5), inhi...
Effects of various selective phosphodiesterase (PDE) inhibitors on muscle contractility and cyclic nucleotide contents in guinea pig taenia coli were investigated. Forskolin and sodium nitroprusside inhibited carbachol (CCh)-induced contraction in a concentration-dependent manner. Various selective PDE inhibitors, vinpocetine (type 1), erythro -9-(...
The effects of the type V phosphodiesterase (PDE V) inhibitors, MBCQ, zaprinast and dipyridamole, on the relationship between relaxation and cyclic nucleotide content were investigated in rat ileal smooth muscle. Each of MBCQ (0.01-10 microM), zaprinast (0.1-100 microM) and dipyridamole (0.1-100 microM) inhibited carbachol (CCh; 10 microM)-induced...
The leaves of Gymnema inodorum (GI) have been known to be effective for some diseases including diabetes mellitus, rheumatic arthritis and gout. The crude saponin mixtures extracted from GI leaves inhibited glucose absorption in the isolated intestinal tract and suppressed the increased blood glucose in rats. In this study, we examined the relation...
In the present paper, we examined a mechanism of the papaverine induced relaxation in the smooth muscle of non-pregnant rat uterus. The hyperosmotic 65 mM KCl (H-65K+)-or oxytocin-induced contraction in the uterus was inhibited by an addition of papaverine in a concentration-dependent manner. Papaverine did not increase both cAMP and cGMP contents...
In guinea pig urinary bladder, the hyperosmotic 65 mM KCI (H-65K+)- or carbachol (CCh)-induced contraction was inhibited by an addition of papaverine in a concentration-dependent manner. The cAMP content of the muscle in the presence of H-65K+ or CCh was increased by papaverine only at the higher concentration of 100 microM, but cGMP content was no...
In guinea pig urinary bladder, the hyperosmotic 65 mM KC1 (H-65K⁺)- or carbachol (CCh)-induced contraction was inhibited by an addition of papaverine in a concentration-dependent manner. The cAMP content of the muscle in the presence of H-65K⁺ or CCh was increased by papaverine only at the higher concentration of 100 μM, but cGMP content was not af...
Papaverine (0.3-100 microM) more potently inhibited phenylephrine (1 microM)-induced contraction than 65 mM K+-induced contraction of the aorta, while it equally inhibited contractions induced by 65 mM K+ and carbachol (1 microM) in ileal smooth muscle. In phenylephrine-treated aorta, papaverine (1-10 microM) increased the cAMP and cGMP content. Ho...
The effects of various selective phosphodiesterase (PDE) inhibitors on muscle contractility in guinea pig ileal longitudinal smooth muscle were investigated. 1) 3-Isobutyl-1-methyl xanthine (IBMX) or zaprinast markedly inhibited the high K(+)- or carbachol (CCh)-induced contraction and increased cGMP content of the muscle strip in a concentration-d...
Gymnema sylvestre (GS) is one of the Asclepiad strains that grows in South-east Asia. Their therapeutic effects for treating diabetes mellitus, rheumatic arthritis and gout have been well known for a long time. However, the problem is that GS suppresses sweetness and tastes bitter. For this study, we chose Gymnema inodorum (GI) instead of GS, since...
Extracts containing gymnemic acids, which were extracted from the leaves of Gymnema sylvestre (GS) as nine fractions, were evaluated for their effects on a high K(+)-induced contraction of guinea-pig ileal longitudinal muscles, on glucose transport mediated by the difference of glucose-evoked transmural potential difference (delta PD) in the invert...
To investigate the contractility of pulmonary arterial smooth muscle and the relation between pulmonary hypertension and endothelium-derived relaxing factor in canine heartworm disease.
18 noninfected control and 9 heartworm-infected dogs.
Mean pulmonary arterial blood pressure was measured in vivo, and tension of pulmonary arterial strips was meas...
Two substances identified as ((3 beta, 4 alpha, 16 beta, 21 beta, 22 alpha)-21-tigloxy-16, 22, 23, 28-tetrahydroxyolean-12-en-3-yl-beta D-glucopyranosiduronic acid) (GA1) and ((3 beta, 4 alpha, 16 beta, 21 beta, 22 alpha)-21-(2-methylbutyroxy)-16, 22, 23, 28-tetrahydroxyolean-12-en-3-yl-beta-D-glucopyranosiduronic acid) (GA2) identified among the g...
Effects of phorbol ester, 12-deoxyphorbol 13-isobutyrate (DPB), on muscle tension and cytosolic Ca2+ ([Ca2+]i) level was investigated in rat anococcygeus muscle in comparison with other smooth muscles. 1) DPB (10(-6) M) induced a large contraction and an elevation of [Ca2+]i level in rat aorta and small and rhythmic changes in tension and [Ca2+]i l...
The effect of TCV-309, a newly developed platelet activating factor (PAF) antagonist, on the wet/dry weight ratio of the lung (index of pulmonary edema) and the pulmonary surface activity (index of pulmonary compliance) was evaluated in comparison with that of CV-3988 (PAF-antagonist). Administration of TCV-309 (1 mg/kg) or CV-3988 (10 mg/kg) signi...
A contractile property of phenylephrine (PE), alpha 1 agonist, on rat anococcygeus muscle was compared with that on rat aorta by simultaneously measuring changes in intracellular Ca2+ ([Ca2+]i) level and muscle tension. (1) PE (0.1-30 microM) and high K+ induced a sustained increases in [Ca2+]i level and muscle tension of both the muscles. (2) An a...
The mechanism of the inhibitory effect of Li+ on contraction was examined in guinea pig ileal longitudinal smooth muscle. Li(+)-substitution (68.4 mM) reversed contractions induced by high K+ (45.4 mM), carbachol (1 microM) and histamine (1 microM) without changing the cytosolic Ca2+ level. Li+ also had no effect on the increase in 45Ca2+ uptake st...
The therapeutic effects of TCV-309, a novel platelet activating factor antagonist, on hemodynamics in endotoxin-induced shock were evaluated. Ten Beagle dogs were used under general anesthesia and artificial ventilation. After intravenous injection of endotoxin (3 mg/kg), TCV-309 (1 mg/kg) was administered intravenously to the dogs. The results sho...
The effect of CV-3988, a platelet activating factor antagonist, in the treatment of endotoxic shock was evaluated from the changes in plasma 6-keto-PGF1 alpha and thromboxane B2 concentrations. The animals consisted of 10 beagle dogs anesthetized with pentobarbital sodium and divided into a treatment group (n = 5) and a control group (n = 5). Endot...
The effect of CV-3988, a platelet activating factor antagonist, in the treatment of endotoxic shock was evaluated from the changes in plasma 6-keto-PGF1α and thromboxane B2 concentrations. The animals consisted of 10 beagle dogs anesthetized with pentobarbital sodium and divided into a treatment group (n=5) and a control group (n=5). Endotoxic shoc...
The therapeutic effect of ulinastatin (25,000 U/kg, i.v.) on endotoxin-induced shock was compared with that of methylprednisolone (30 mg/kg, i.v.) in 17 anesthetized dogs. Both of these drugs had almost the same tendency to improve the hemodynamics, arachidonate cascade metabolites and pulmonary surface activity. There was little difference between...
The therapeutic effect of dibutyryl cyclic AMP (DBcAMP) in endotoxic shock was evaluated, using 11 dogs with experimentally-induced endotoxic shock (5 in DBcAMP group and 6 in control group) under general anesthesia. The DBcAMP group was treated by single intravenous injection of DBcAMP (10 mg/kg) at 15 min before inoculation with endotoxin (3 mg/k...
A shock model was experimentally produced by intravenous injection of a lethal dose (3 mg/kg) of endotoxin under general anesthesia induced by pentobarbital sodium using 7 beagles. The effect of this endotoxic shock on the reticuloendothelial function was investigated. The blood endotoxin concentration peaked immediately after administration and de...
Accuracy assessment was undertaken under varying hemodynamic conditions for a lung water volume measurement device which is based on the principle of a double indicator dilution method using heat and sodium ions. Changes in extravascular thermal volume were investigated in dogs with endotoxin-induced shock. The isoproterenol- or propranolol-induced...
The inhibitory effect of tiamulin, an antibiotic produced by Pleurotus mutilis, on contractile and electrical responses in isolated thoracic aorta and cardiac muscle of guinea-pigs was studied. In the thoracic aorta, tiamulin with an IC50 of 9.7 x 10(-6) M inhibited sustained contractions induced by isosmotically added 60 mM KCl. The inhibitory eff...
The therapeutic effect of ulinastatin, an inhibitor of the protease activity, on endotoxin shock was evaluated using 17 Beagle dogs. Single intravenous injection of ulinastatin at a dose of 5,000 or 25,000 U.kg-1 failed to suppress the endotoxin-induced circulatory disturbance but significantly inhibited increases in pulmonary arterial pressure and...
The mechanism of endothelium-dependent relaxation induced by pirarubicin, (2''R)-4'-O-tetrahydropyranyladriamycin, THP, or carbachol was investigated in the rat isolated aorta. The relaxant effect of THP (1.5 x 10(-6)-4.5 x 10(-5) M) or carbachol (10(-8)-10(-4) M) on the aorta with endothelium was decreased by lowering Ca2+ in the medium. The relax...
The mechanism of relaxation produced by pirarubicin [(2"R)-4'-O-tetrahydropyranyladriamycin, THP] has been studied in rat isolated aorta. THP (1.5 x 10(-6)-4.5 x 10(-5) M) markedly relaxed contractions induced by noradrenaline (10(-7) M) in the aorta with endothelium, but not in that without endothelium. The relaxation induced by 1.5 x 10(-5) M THP...
Tiamulin with an IC50 of 1.7 x 10(-6) M inhibited both the rapid and sustained contractions induced by hyperosmotically added 60 mM K+ (Hyper 60 K+) without changing the membrane potential in the intestinal muscle. Tiamulin inhibition (2 x 10(-6)-2 x 10(-5) M) of the Ca(2+)-induced contraction in depolarized muscle was competitively antagonized by...
In the present experiment, we studied the inhibitory mechanism of Na+ depletion on high K(+)-induced contraction by simultaneously measuring reduced pyridine nucleotides (PNred) or oxidized flavoproteins (FPox) fluorescence and contractile tension of the guinea pig ileal longitudinal muscle. Tension, PNred and FPox were all reversibly increased by...
In the present study we examined the effects of pirarubicin [(2"R)-4'-O-tetrahydropyranyladriamycin, THP] on a cardiovascular system. An injection of THP (0.39-3.13 mg/kg, i.v.) reduced the mean blood pressure and caused an increase in the respiratory air rate in anesthetized rats. At 1.5 x 10(-6)-1.5 x 10(-5) M, THP markedly relaxed a contraction...
Tiamulin with an IC50 of 1.7 × 10⁻⁶M inhibited both the rapid and sustained contractions induced by hyperosmotically added 60 mM K⁺ (Hyper 60 K⁺) without changing the membrane potential in the intestinal muscle. Tiamulin inhibition (2 × 10⁻⁶-2 × 10⁻⁵ M) of the Ca²⁺-induced contraction in depolarized muscle was competitively antagonized by raising e...
In the present experiment, we studied the inhibitory mechanism of Na⁺ depletion on high K +-induced contraction by simultaneously measuring reduced pyridine nucleotides (PNred) or oxidized flavoproteins (FPox) fluorescence and contractile tension of the guinea pig ileal longitudinal muscle. Tension, PNred and FPox were all reversibly increased by t...
In the present paper, effects of high K+/Na+ deficient solution on the rat uterus with the progress of the pregnancy were examined on the mechanical response and wet weight. The progress of pregnancy was divided in four stages, early stage (Day 4 and 5 of pregnancy), middle stage (Day 8-10), late stage (Day 14 and 15) and end stage (Day 21). In the...
The tonic contractions induced in the guinea-pig ileal longitudinal muscle by 60 mM KCl, carbachol, histamine or A23187 were inhibited similarly by Li+-substituted solution. There was a good correlation between the Li+-induced inhibition of contractions induced by these stimulants and the intracellularly accumulated Li+ content. In the experiment w...
In guinea pig ileal muscle strips, trifluoperazine (TFP) inhibited the high K⁺-induced contraction with an IC50 of 1.9 /M and the Ca2 + -induced contraction in skinned fiber with an IC50 of 44 /M. TFP decreased the high K⁺-induced increase in cytoplasmic Ca²⁺ level at the concentration 3 /¿M, which did not inhibit the contraction in skinned fiber....
In guinea pig ileal muscle strips, trifluoperazine (TFP) inhibited the high K⁺-induced contraction with an IC50 of 1.9 μM and the Ca²⁺-induced contraction in skinned fiber with an IC50 of 44 μM. TFP decreased the high K⁺-induced increase in cytoplasmic Ca²⁺ level at the concentration 3 μM, which did not inhibit the contraction in skinned fiber. It...
The effects of Li+ substitution for external Na+ in the medium on a 60 mN KCl (60K+)-induced contraction were compared in the ileal longitudinal smooth muscles isolated from monkey, rabbit, guinea pig and rat. Li+ substitution inhibited the 60K+-induced contraction in the ileum of all the animal species. Greater inhibitory effect was observed with...
In the present paper, effects of high K+/Na+ deficient solution on the rat uterus were examined on the mechanical response, wet weight of the tissue or rate of oxygen consumption, and they were compared with those in rat urinary bladder. In the uterus, isosmotic substitution of K+ for Na+ in a physiological salt solution (PSS) induced a contraction...
In guinea-pig ileal longitudinal smooth muscle, both palytoxin (PTX) and carbachol (CCh) increased K+ efflux with an EC50 of 1.8 X 10(-10) M and 4.1 X 10(-7) M, respectively. Atropine (10(-6) M) did not inhibit the K+ efflux due to PTX (3 X 10(-9) M), but completely inhibited the efflux due to CCh (10(-5) M). External Ca2+ removal and verapamil (10...
The mechanism of the inhibitory effect of caffeine was investigated using vascular smooth muscle of rabbit aorta and intestinal smooth muscle of taenia isolated from guinea‐pig caecum.
Caffeine, 0.5–10 m m , relaxed the sustained contraction induced by 65.4 m m KCl or 10 ⁻⁶ m noradrenaline in aorta, and by 45.4 m m KCl or 10 ⁻⁶ m carbachol in taeni...
In the present experiments, we investigated contractions of guinea-pig vas deferens or seminal vesicle in various kinds of high K+ solution. The vas deferens showed a phasic contraction followed by a tonic one in hyperosmotic 65 mM KCl (hyper-65K+), isosmotic 60 mM or 120 mM KCl solution. However, isosmotic 154 mM KCl (iso-154K+) solution induced a...
In the present paper, effects of high K⁺/Na⁺ deficient solution on the rat uterus were examined on the mechanical response, wet weight of the tissue or rate of oxygen consumption, and they were compared with those in rat urinary bladder. In the uterus, isosmotic substitution of K⁺ for Na⁺ in a physiological saltsolution (PSS) induced a contraction...
In guinea-pig ileal longitudinal smooth muscle, both palytoxin (PTX) and carbachol (CCh) increased K⁺ efflux with an EC50 of 1.8×10⁻¹⁰ M and 4.1 ×10⁻⁷ M, respectively. Atropine (10⁻⁶ M) did not inhibit the K⁺ efflux due to PTX (3×10⁻⁹ M), but completely inhibited the efflux due to CCh (1Cr⁵ M). External Ca²⁺ removal and verapamil (10⁻⁵ M) did not c...
An inhibitory effect of beauvericin, a cyclodepsipeptide, on a high K+-induced contraction in guinea-pig taenia coli was compared with those of verapamil, an organic Ca2+ antagonist, and monensin, an inhibitor of mitochondrial respiration. Beauvericin (10(-5) M), verapamil (5 x 10(-7) M) or monensin (10(-6) M) markedly inhibited the tonic contracti...
The relaxant action of amiloride was investigated in the smooth muscles of guinea pig taenia ceci and chicken gizzard. Amiloride inhibited the contractions induced by high K+ (45.4 mM) and carbachol (10 microM) in the taenia with the concentrations needed to induce 50% inhibition (IC50) of approximately 41 microM. A prolonged incubation period (gre...
The inhibitory effects of nicorandil, nitroglycerin and isosorbide dinitrate on the contractions induced by 10−6 M norepinephrine or by 65.4 mM K+ were compared in the vascular smooth muscle of rabbit aorta. These compounds relatively selectively inhibited the contraction induced by norepinephrine. Norepinephrine induced a sustained contraction in...
Hypertonic 60 mM KCl (H 60K+) solution induced a phasic contraction followed by tonic one in the longitudinal (long.) and circular (circ.) muscles of cat ileum. Verapamil inhibited the tonic contraction in the long. or circ. muscle with IC50 of 2.0 X 10(-8) M or 1.0 X 10(-7) M, respectively. The sensitivity of the long. muscle to verapamil was high...
Characteristics of caffeine-induced contraction were compared with those of high K+- and norepinephrine-induced contractions in order to evaluate the participation of the Ca++-induced Ca++-release (CCR) from storage site in the vascular smooth muscle of rabbit aorta. Caffeine induced a transient contraction in a solution without MgCl2. One mM Mg++...
A toxic component (pCrTX) of jellyfish Carybdea rastonii (10(-8)-10(-6)g/ml) caused a contraction in both rat aorta and guinea-pig taenia coli which was partially inhibited by indomethacin or aspirin. pCrTX (10(-7)-10(-6)g/ml) relaxed the norepinephrine-induced contraction in rat aorta which was inhibited by removing endothelium or by adding methyl...
PTX (10(-8)M) induced a rapid increase followed by a gradual decrease in muscle tension in normal physiological salt solution (PSS), while it induced a slow increase in muscle tension in low-Na+ solution. These contractions were inhibited by Ca2+ channel blockers, verapamil and nicardipine. PTX rapidly increased tissue Na+ and decreased tissue K+ c...
The effects of a potent marine toxin, palytoxin (PTX), were investigated on the contractile responses in the isolated rat aorta with or without endothelium. PTX in the concentrations of 10–13–10–11 mol/l showed little effect on the resting tension of the vessel with or without endothelium. PTX, 10–10 mol/l, induced a small contraction in the aorta...
An inhibitory effect of beauvericin, a cyclodepsipeptide, on a high K⁺-induced contraction in guinea-pig taenia coli was compared with those of verapamil, an organic Ca²⁺ antagonist, and monensin, an inhibitor of mitochondrial respiration. Beauvericin (10⁻⁵ M), verapamil (5×10⁻⁷ M) or monensin (10⁻⁶ M) markedly inhibited the tonic contraction, whil...
Effects of the toxic component of jellyfish (Carybdea rastonii) (pCrTX) on the smooth muscle tension of isolated rabbit thoracic aorta were examined. pCrTX, at concentrations higher than 10(-7) g/ml, caused slowly developing tension that reached its maximum after about 1 hr. This contraction was partially inhibited by pretreatment of the tissue wit...
Effects of a Ca ²⁺ channel facilitator, CGP 28,392, on smooth muscle contractions were examined in order to delineate characteristics of Ca ²⁺ channels in rabbit and rat aortae and guinea‐pig taenia caeci.
Application of increasing concentrations of KCl induced contractile responses in these smooth muscles and CGP 28,392 shifted the concentration‐r...
Effects of harmaline and other harmala alkaloids on the contractions induced in the vascular smooth muscle of rabbit aorta and intestinal smooth muscle of taenia isolated from guinea‐pig caecum were examined.
In rabbit isolated aorta, harmaline inhibited the sustained contraction induced by 65.4 mM K ⁺ with an IC 50 (concentration needed for 50% in...
Effects of Sr substitution for Ca on the contractions due to Ca influx in the aortae of rabbit and rat and the guinea-pig taenia coli were examined in order to characterize the pathways of Ca influx activated by either high K or receptor agonists. In normal solution containing Ca, high K increased both muscle tension and 45Ca uptake in rabbit and r...
Effects of trifluoperazine (TFP, 10(-5) M), trifluoperazine sulfoxide (TFP-SO, 10(-5) M), N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide (W-7-, 10(-4) M), N-(6-aminohexyl)-1-naphthalenesulfonamide (W-5, 10(-4) M) and verapamil (10(-5) M) on the endothelium-dependent relaxation of the contractions induced in the isolated rabbit aorta were studie...
Mechanism of inhibitory action of sodium nitroprusside in vascular smooth muscle of rabbit aorta was examined. Sodium nitroprusside inhibited the 1 X 10(-6) M norepinephrine-induced contraction with IC50 (concentration to induce 50% inhibition) of 1.40 X 10(-7) M, but had little effect on the 65.4 mM K-induced contraction. In contrast, verapamil ha...
Effect of verapamil on the spontaneous transmitter release in the presence and absence of external calcium and manganese ions was examined by monitoring the frequency of miniature end-plate potentials (MEPPs) in the rat diaphragms. Verapamil (25 to 50 microM) caused a sustained increase in the MEPP frequency in a normal Ringer solution and a transi...
Palytoxin (PTX) caused K+ release from rabbit erythrocytes which was dependent on the concentrations of extracellular Ca2+ and PTX. In a Ca2+-free solution, PTX still caused a slow K+ release. An intracellular Ca2+ antagonist, TMB-8, an intracellular Ca2+ chelator, quin 2, and calmodulin inhibitors, prenylamine, W-7 and W-5, inhibited the PTX-induc...
The inhibitory effects of endothelium-derived relaxing factor (EDRF) on the contractions induced by norepinephrine and clonidine in rat aorta were examined. Carbachol induced a relaxation of norepinephrine-induced contraction in rat aorta with endothelium. Removal of endothelium inhibited the carbachol-induced relaxation and increased the magnitude...
Palytoxin (PTX), at extremely low concentrations (0.01-1 nM), caused K+ release from rabbit erythrocytes. Among the various chemical compounds tested, cardiac glycosides potently inhibited the PTX-induced K+ release. The order of inhibitory potency (IC50) was cymarin (0.42 microM) greater than convallatoxin (0.9 microM) greater than ouabain (2.3 mi...
Citations
... It has also been shown that Li + -mduced relaxation is antagonized by the increase in external Ca 2 * and that intracellular^ accumulated Li + inhi bits 45 Ca uptake, suggesting that both cellular Lr and Na + inhibits the high K. -induced in crease in Ca 2+ influx in smooth muscle(5,7,8). However, when the intracellular free Ca 2f level and contractile tension were simul taneously recorded in guinea pig ileal strips loaded with a Ca 2+ indicator, fura 2, Li' substitution inhibited the 60K + -induced con traction but not the intracellular tree Ca 24 level(17). Moreover, in chemically skinned fiber of guinea pig ileum, the Ca 2+ (10" 6 M)-induced contraction was inhibited by Li* and 50% inhibition of tension in intact tissue ot guinea pig ileum (M. ...
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... Initially, NADPH (final concentration = 1 mM) (Lot#: 00616) and MLMs, RLMs, DLMs, and HLMs (protein concentration = 0.56 mg/mL) were added individually to potassium phosphate buffer and incubated for 10 min at 37 • C. Subsequently, BEA and the control were prepared with 5 µL DMSO and 495 µL acetonitrile (ACN), and then spiked into the reaction mixture to achieve a final BEA concentration of 1 µM. Samples were withdrawn from the reaction mixture at different times (5,15,30,45, and 60 min), and the reaction was terminated using acetonitrile. The positive control compound testosterone was incubated in parallel with the BEA samples. ...
... Application of hyperosmotically-added high-K + solution induced a sustained contraction, while an isosmotically-substituted high-K + , Na + -deficient solution induces contraction followed by gradual relaxation in various smooth muscles [5][6][7][15][16][17][18][19][20][21]. The possible mechanism of these decreases in muscle contractility of tonic muscle is swelling of the cells, as in rabbit aorta [19]. ...
... De referir, no entanto, que o efeito espasmolítico do músculo liso por parte da papaverina não se deve unicamente à inibição da PDE10, devendo também estar envolvidas outras PDE (particularmente a PDE4), donde resulta um aumento dos nucleótidos cíclicos, responsável pelo relaxamento da musculatura lisa. Além da inibição das PDE, está também descrito um mecanismo de ação que envolve a inibição da fosforilação oxidativa39,40 .Tabela 1 -Inibidores seletivos das PDE utilizados na terapêutica farmacológica e respetivas indicações terapêuticas autorizadas 70-72 *MilrinonaTratamento a curto prazo, por via intravenosa, da insuficiência cardíaca, incluindo situações de baixo débito, no pós-cirurgia cardíaca. Autorizado para utilização na terapêutica farmacológica humana no Japão 77 . ...
... In conclusion, PF-04449613 exerted positive inotropic effect both in vivo and in vitro by enhancing SERCA2a activity. [3] ，研究表明 PDE9 抑制剂具有广泛的生 理和药理作用。由于 PDE9 抑制剂能够快速提升细 胞内的 cGMP 浓度，早期被开发用于神经性疾病 [4] ， 后有研究表明其还具有提高认知功能 [5] 、抗抑郁及 焦虑 [6] 、改善学习功能 [7] 、抗乳腺癌 [8] 的药理作用。 PDE9 抑制剂目前正进行临床试验，用于老年痴呆 及精神分裂症的治疗 [9] 。此外，PDE9 抑制剂增加 细胞内 cGMP 浓度而舒张气管平滑肌，具有治疗气 道高反应性疾病的潜力 [10] 。 PDE9 在扩张性心力衰竭 ( 心衰 ) 及射血分数保 留型心衰患者的心肌内表达增加 [11] ...
... Nghiên cứu của T. Kaneda et al., (2018) cho thấy (64) có tác dụng ức chế co thắt bàng quang chuột gây ra cho carbachol [61]. Các polyphenol chiết xuất từ loài L. japonica như luteolin (23), acid 3,4-di-O-caffeoylquinic (84), acid 3,4-di-Ocaffeoylquinic methyl ester (70), methyl caffeate (96), acid protocatechuic (104) đóng vai trò ức chế hoạt hóa tiểu cầu và bảo vệ tế bào chống lại tổn thương tế bào gây ra do H2O2 [62]. ...
... Malus baccata extracts containing phloridzin was reported to have radioprotective and immunomodulatory activities (Wang et al. 2016a). In rat ileum, phloridzin also was found to inhibit the high K + -induced contraction through the SGLT1 inhibition (Kanda et al. 2017). Phloridzin treatment was also found to induce enhancement of erectile function (Park et al. 2019) (Table 2). ...
... However, changes in the contraction of smooth muscle differ between organs and tissues. Aeration of N 2 instead of O 2 , abolishes high K + -induced contraction in the guinea pig taenia coli [3,4,20,21] and porcine iris sphincter muscle [8]. In addition, sodium cyanide (NaCN), aerobic metabolism inhibitor, significantly suppresses the high K + -induced contraction in guinea pig urinary bladder [6]. ...
... The slight vasodilation observed in the absence of 7 (Fig. 7b) or light irradiation (Fig. 7c) was probably induced by DMSO, since it has been reported that DMSO induces vasodilation in rat aorta by inhibiting Rho-kinase. 35 While the vasodilation produced by caged NOs was transient and only occurred during irradiation, 7 induced prolonged vasodilation even aer the irradiation was stopped. These results suggest that 7 could be a candidate photovasodilator for treating chronic hypertensive diseases. ...
... It is also well known that the trachea is one of the organ, which has animal species difference for drug reaction [11,19]. We have continued research on the agents related to signal transduction of cAMP and cGMP in bovine and porcine smooth muscle [6][7][8][9]. ...
