• Korean Journal of Pharmacognosy
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• v.24 no.2
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• pp.140-152
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• 1993

This study was attempted to investigate the effect of Ganoderma lucidum extract on digestive system in experimental animals. Ganoderma lucidum water extract (GWE) was found to be promoted the charcol transport rate in the small intestine of mice. GWE exhibited the augmentation of spontaneus movement(motility) and contractile response(tension) in the ileum and colon strips of rabbit, and these action were inhibited by atropine. GWE given intraduodenaly(i.d.) exhibited the significant increase of gastric acid secretion in pylorus-ligated rats. GWE inhibited the formation of some experimental gastric ulcers(pylorus ligation ulcer i.d., indomethacin-induced ulcer p.o., i.d. and aspirin-induced ulcer p.o.) in rats, which are considered to relate to a protective action. GWE and EtOH extract(water soluble phase) were remarkably increase of bile excretion, when administration of i.d., intravenation(i.v.) and per os (p.o.) compared with normal-control group. GWE was observed antibacterial activity aginst several intestinal microoganisms and others bacteria in vitro test.

• Biomolecules & Therapeutics
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• v.13 no.1
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• pp.48-58
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• 2005

The present study was conducted to investigate the effects of nicorandil on arterial blood pressure and vascular contractile responses in the normotensive anesthetized rats and to establish the mechanism of action. Nicorandil (30~300 ${\mu}g/kg$) given into a femoral vein of the normotensive anesthetized rat produced a dose-dependent depressor response. These nicorandil-induced hypotensive responses were not affected by pretreatment with atropine (3.0 mg/kg, i.v.) or propranolol (2.0 mg/kg, i.v.), while markedly inhibited in the presence of chlorisondamine (1.0 mg/kg, i.v.) or phentolamine (2.0 mg/kg, i.v.). Futhermore, after the pretreatment with 4-aminopyridine (1.0 mg/kg/30 min, i.v.) or glibenclamide (50.0 ${\mu}g/kg$/30min) into a femoral vein made a significant reproduction in pressor responses induced by intravenous norepinephrine. In he isolated rat aortic strips, both phenylephrine (10$^{-5}$ M)- and high potassium (5.6 ${\times}\;10^{-2}$ M)-inducedcontractile responses were dose-dependently depressed in the presence of nicorandil (25~100 ${\mu}M$). Collectively, these experimental results demonstrate that intravenous nicorandil causes a dose-dependent depressor action in the anesthetized rat at least partly through the blockade of vascular adrenergic ${\alpha}_1$-receptors, in addition to the well-known mechanism of potassium channel opening-induced vasorelaxation.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.4
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• pp.333-338
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• 2000

We have examined whether bile acids can affect the electrical and mechanical activities of circular smooth muscle of canine colon and ileum, using isometric tension measurement or patch clamp technique. It was found that a dilution of canine bile $(0.03{\sim}2%\;by\;volume)$ enhanced or inhibited the amplitude of spontaneous contractions. An individual component of bile, deoxycholic acid (DCA) enhanced the frequency and amplitude of the spontaneous contractile activity at $10^{-6}\;M,$ while DCA at $10^{-4}\;M$ inhibited the contraction. Similarly, the response to cholic acid was excitatory at $10^{-5}\;M$ and inhibitory at $3{\times}10^{-4}\;M.$ Taurocholic acid at $10^{-4}\;M$ enhanced the amplitude of muscle contraction. Electrically, canine bile at 1% reversibly depolarized the colonic myocytes under current clamp mode. Bile acids also elicited non-selective cation currents under voltage clamp studies, where $K^+$ currents were blocked and the $Cl^-$ gradient was adjusted so that $E_{Cl}^-$ was equal to -70 mV, a holding potential. The non-selective cation current might explain the depolarization caused by bile acids in intact muscles. Furthermore, the bile acid regulation of electrical and mechanical activities of intestinal smooth muscle may explain some of the pathophysiological conditions accompanying defects in bile reabsorption.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.6
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• pp.463-469
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• 2000

It has been well known that 4-aminopyridine (4-AP) has an excitatory effect on vascular smooth muscle due to causing membrane depolarization by blocking $K^+-channel$. However, we observed that 4-AP had an inhibitory effect on the mesenteric artery of rat. Therefore, we investigated the mechanism of 4-AP-induced vasorelaxation. The mesenteric arcuate artery and its branches were isolated and cut into ring. The ring segment was immersed in HEPES-buffered solution and its isometric tension was measured. 4-AP $(0.1{\sim}10\;mM)$ induced a concentration-dependent relaxation, which was unaffected by NO synthase inhibitor, $N^G-nitro-L-arginine$ methylester $(100\;{\mu}M)$ or soluble guanylate cyclase inhibitor, methylene blue $(100\;{\mu}M).$ Glibenclamide $(100\;{\mu}M)$, ATP-sensitive $K^+$ channel blocker, did not exert any effect on the 4-AP-induced vasorelaxation. 4-AP relaxed the sustained contraction induced by 100 mM $K^+$ or $Ca^{2+}$ ionophore, A23187 $(100\;{\mu}M)$ in a dose-dependent manner. In addition, 4-AP significantly decreased the phasic contractile response to norepinephrine in the absence of extracellular $Ca^{2+}$. However, 4-AP did not block the $^{45}Ca$ influx of rat aorta. From the above results, we suggest that 4-AP may not block the $Ca^{2+}$ influx through $Ca^{2+}-channel,$ but act as a nonspecific vasorelaxant in arterial smooth muscle.

• The Korean Journal of Pharmacology
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• v.11 no.1 s.17
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• pp.15-18
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• 1975

The effect of skin extracts of Korean amphibian, poisonous snake and fresh-water fish were determined for their caerulein-like action on rabbit gall bladder strips. The isolated gall bladder strips were prepared according to the technique described by Amer and Becvar(1969). The strips were placed in a bath containing 100ml 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. In this rabbit gall bladder strip caerulein produced contraction of CCK-PZ type. The skin extract of Korean amphibian also elicited similar contraction as caerulein, which extracted from Australian amphibian, Hyla caerulea, by Erspamer et al. The calculated amount was approximately $2{\mu}g$ caerulein per gram of skin tissue in Korean amphibian and the potency was about 1/200 of that seen in Australian amphibian. The contraction of gall bladder strip by our amphibians occurs in decreasing order; Rana Nigromaculata coreana Okada, Rana nigromaculata Hallowell, Hyla arborea japonica Gunther and Bombina orientalis Boulenger. The skin extracts of poisonous snake and fresh-water fish produced no caerulein-like activity.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1993.05a
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• pp.68-68
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• 1993

Immunohistochemistry combined with electron microscopy was employed to investigate the distribution of substance P -immunoreactive(SP-IR) nerve fibers in the tracheal submucosal gland of cats. SP-IR nerve fibers were found to form network around the glands. Numerous varicosities were also detected within the basement membrane of the acini and secretory tubules. All the intraglandular varicosities showed close spatial contact with serous cells, mucous cells and myoepithelial cells. Our findings suggest that SP-induced mucus secretion from tracheal submucosal glands in cats may be caused not only by glandular contractile response of myoepithelial cells but also by direct stimulation to both serous and mucous cells.

• The Korean Journal of Physiology
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• v.11 no.2
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• pp.51-56
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• 1977

In Nembutal anesthetized cats, the sobmaxillary duct was cannulated with polyethylene tube, and effects of stimulation of the chorda tympani and cervical sympathetics on, the submaxillary secretion and intraluminal pressure of the submaxillary duct were observed. The stimulation of tile chorda tympani elicited a profuse salivary secretion. The stimulation of the cervical sympathetics evoked only a scanty flow, and on repeated stimulation of the nerve salivary flow response gradually diminished and finally the flow ceased. In this state the salivary flow by the sympathetic stimulation was resumed after the stimulation of the chorda tympani. Atropine abolished these responses to nerve stimulation. Intraluminal pressure of the submaxillary duct was abruptly increased and remained on a plateau during the stimulation of the chorda tympani, whereas sympathetic stimulation elicited moderate increase of the intraluminal pressure which did not remain in spite of continued stimulation. These results suggest that scanty salivary flow induced by cervical sympathetic stimulation is not real secretion but simple elimination of the saliva already present in the duct due to contraction of the contractile elements known to exist in the duct wall.

• The Korean Journal of Physiology
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• v.24 no.2
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• pp.353-362
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• 1990

Fluoride (F-), a known stimulator of G-protein, induced strong contraction in rabbit trachealis muscle. $AlCl_3\;(5{\sim}20\;{\mu}M)$, which is required for G-protein stimulation by $F^-$, potentiated the contractile response to $F^-$. $Ca^{2+}-removal$ and verapamil, a calcium channel blocker, inhibited the fluoroaluminate-induced contraction. Fluoroaluminate increased $^{45}Ca$ influx in the absence and presence of verapamil. In heparin-loaded muscle high $K^+-induced$ contraction was not affected, but acetylcholine and fluoroaluminate-induced contractions were inhibited. The fluoroaluminate-induced contraction was partially relaxed by isoproterenol, a stimulator of adenylate cyclase. Pertussis toxin partially inhibited fluoroaluminate-induced contraction and potentiated isoproterenol-induced relaxation in the presence of fluoroaluminate, but had no effect on acetylcholine-induced contraction and the isoproterenol-induced relaxation in the presence of acetylcholine. These results suggest that fluoroaluminate has the ability to stimulate at least two putative G-proteins in rabbit trachealis muscle; One causes $Ca^{2+}$ influx through the potential-operated $Ca^{2+}$ channel and the other induces intracellular $Ca^{2+}$ release by the increase of inositol-1, 4, 5-triphosphate.

• Proceedings of the Korea Society of Environmental Biology Conference
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• 2003.11a
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• pp.86-91
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• 2003

In this study, in order to examine whether salt and heat shock stress would alter or not contraction and relaxation of isolated rat aorta. Under anesthesia with sodium pentobarbital(50 mg Kg$^{-1}$ i.p.), male Sprague Dawley rats weighing 300-330 g were subjected to 0, heat shock combined salt stress, where as the sham group was left at modified Krebs-bicarbonate solution. To measure contractile response of vascular ring preparation isolated from rat was determined in organ bath and was recorded on physiograph connected to isometric transducer. And the strip was checked for expression of heat shock protein(Hsps) by means of western blotting. The combination group of heat and 50 mM NaCl group increased vascular contractility, and the heat and 150 mM NaCl group decreased vascular contractility for 5 hours, and then recovered for 8 hours compared to that of control. Expressin of Hsp 70 of vascular muscle of rat aorta more increased by combination of heat and NaCl treatment than those of single treatment of heat or NaCl treatment, and vascular Hsp 70 showed a little decrease at 8 hours compared at 5 hours. These result indicate that mixed environmental stress either increased or decreased in vascular contractility by combination of heat and NaCl concentration.

• The Korean Journal of Physiology and Pharmacology
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• v.5 no.1
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• pp.47-53
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• 2001

Drinking excessive alcohol has been recognized as a risk factor for hypertension. However, the mechanism by which alcohol intake causes hypertension still remains elusive. We tested the hypothesis that ethanol itself acts as a stress factor on vasculature and indirectly modulates vascular contractility. After end of exposure to 1, 2.5 and 5% ethanol for 45 min, rat aortic strips were subjected to contractile responses, immunoblot for Hsp70 and the measurement of levels of myosin light chain phosphorylation. Exposure to 5% ethanol not only augmented contractions to KCl or phenylephrine, but also increased expression of Hsp70 and the levels of myosin light chain phosphorylation. There were no significant differences in contractions produced by $1\;{\mu}mol/L$ phorbol 12,13-dibutyrate, a protein kinase C activator, whether the tissues were exposed to 5% ethanol or not. This is the first report to show that even short exposure to ethanol has a delayed effect to increase vascular smooth muscle contractility through a modulation of thick filament regulation. It may be a mechanism by which ingestion of alcohol induces hypertension.