• The Korean Journal of Physiology and Pharmacology
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• v.6 no.4
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• pp.225-233
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• 2002

Kanagawa hemolysin (KH), an exotoxin produced from Kanagawa phenomenon-positive Vibrio parahemolyticus, has been shown to possess various biological activities including hemolysis, enterotoxicity, cytotoxicity, and cardiotoxicity. The aim of this study was to investigate the effect of KH on the cardiovascular system and its mechanism, employing in vivo and in vitro experiments of the rat. Intracerebroventricular (icv) administration of 100 mHU KH produced a marked and continuous pressor effect (icv KH-pressor effect), and the icv pressor effect was not repeatable. However, intravenous (iv) injection of the same dose of KH induced a prominent depressor effect (iv KH-depressor effect). The icv KH-pressor effect was inhibited by acid-denaturation, while the iv KH-depressor effect was not. Simultaneous icv administration of the three agents (ouabain, diltiazem, or bumetanide: $10{\mu}g/kg$ each) significantly reduced the pressor effect. The icv KH-pressor effect was inhibited by treatment with iv phentolamine or chlorisondamine, but was not affected by iv candesartan. The iv KH-depressor effect was repeatable and was attenuated by treatment with iv NAME or methylene blue. In vitro experiments using isolated thoracic aorta, $10^{-6}$ M phenylephrine (PE) and 50 mM KCl produced a sustained contraction. In rings contracted with either agents, KH showed relaxant responses in a concentration- dependent fashion and the relaxation (KH-vasorelaxation) was not dependent on the existence of the endothelium. The KH-vasorelaxation in the endothelium-intact rings contracted by PE was abolished by methylene blue treatment. In summary, the present findings suggest that in the icv KH-pressor effect the cation leak-inducing action of KH is implicated, which leads to the increased central sympathetic tone, that the iv KH-depressor effect results from the vasorelaxation via NO-guanylate cyclase system, and that the KH-vasorelaxation is independent of the endothelium and the guanylate cyclase system is involved in it. In conclusion, the mechanism of KH producing the icv pressor effect may not be identical to that of KH producing the iv depressor effect.

• The Korean Journal of Physiology
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• v.25 no.2
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• pp.201-209
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• 1991

The rostral ventrolateral medulla (RVLM) has been established recently as a sympathoexcitatory area. The present study was conducted to investigate whether the somatosympathetic pressor and/or depressor responses are mediated through RVLM in cats anesthetized with ${\alpha}-chloralose$. An occipital craniectomy was performed and ventrolateral medulla were stimulated either electrically or chemically to evoke changes in arterial blood pressure. And then the effect of lesions in the ventrolateral medulla on the changes in blood pressure elicited by the peripheral nerve stimulation was observed. Followings are the results obtained: 1) Pressor areas were found in the ventrolateral medulla, lateral reticular nucleus and rostral dorsal area. 2) Depressor areas were found mainly in the ventrolateral medulla rostral to the pressor areas. 3) Some areas showed biphasic responses: a depressor response to lower frequency and a pressor response to higher frequency stimulation. 4) After electrical lesion in pressor area in RVLM, the somatosympathetic pressor response was abolished or depressed markedly. The somatosympathetic depressor response, however, remained after the lesion. 5) Electrical lesion in the depressor area abolished somatosympathetic depressor response. From the above results it is concluded that somatosympathetic pressor response is mediated through RVLM, while somatosympathetic depressor response is not mediated through RVLM.

• The Korean Journal of Physiology
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• v.16 no.2
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• pp.147-152
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• 1982

The present study was undertaken to investigate effects of Perillae Folium juice on the respiration and blood pressure in cats. Also studied was the mechanism of depressor action of PFJ. The results obtained are as follows; 1) Following administration of 0.2 ml/kg, 0.4 ml/kg and 0.6 ml/kg PFJ into cats the maximum depressor responses observed were 48.5+3.6 mmHg, 56.8+4.3 mmHg and 71.1+2.9 mmHg respectively. 2) Depressor responses to PFJ were blocked makedly by atropine and partially by propranolol. Therefore it is strongly suggested that depressor action of PFJ results mainly from cholinergic effect and partly from activity of ${\beta}-receptor$. 3) After administration of PFJ into cats tachypnea preceded by a short period of apnea was observed invariably.

• The Korean Journal of Physiology
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• v.13 no.1_2
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• pp.35-40
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• 1979

The present study was undertaken to investigate effect of water extracts of the mulberry leaves (MWE) on arterial blood pressure and respiration in cats. And also studied were depressor responses to intravenously administered MWE in the animals pretreated separately with atropine(2.5 mg/kg), propranolol(2 mg/kg), dibenamine (15 mg/kg), and hexamethonium (1.5 mg/kg) in order to find out the mechanism of depressor activity of MWE. The results obtained were as follows; 1) Following intravenous administration of 0.25 ml/kg and 0.5 ml/kg of MWE into the cat the maximum depressor responses observed were $60.2{\pm}2.3\;mmHg$ and $72.3{\pm}1.7\;mmHg$ respectively. 2) Since depressor responses to intravenously administered MWE were partially inhibited by hexamethonium and markedly by atropine, it is strongly suggested that depressor activity of MWE mainly results from its vagal effects. 3) After administration of MWE respiratory rate was invariably increased following a short period of apnea.

• The Korean Journal of Pharmacology
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• v.2 no.1 s.2
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• pp.17-20
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• 1966

The blood pressure responses following repeated injection of bradykinin were observed in the unanesthetized rabbits or rabbits treated with reserpine (0.5mg/kg IV) 24 hours previously. Bradykinin (0.5ug/kg) was injected intravenously at 10 minutes intervals for 5 times. In both groups of rabbits no appreciable changes in the depressor responses to each injection of bradykinin were observed. In the rabbits pretreated with reserpine, however, the more pronounced depressor responses to bradykinin was elicited.

• The Journal of Korean Medicine
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• v.16 no.2 s.30
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• pp.433-446
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• 1995

The present study was carried out to investigate the effect of water extract and 70% ethanol extract from Gastrodiae Rhizoma on cardiovascular activities and plasma levels of catecholamines in unanaesthetized spontaneously hypertensive rats. The depressor response in SHR was observed during three to six hour period after an oral administration of water extract from Gastrodiae Rhizoma(GR). There was a statistically significant correlation between the magnitude of the depressor response induced by an oral administration of water extract from GR and the initial control blood pressure level. The increase in blood pressure induced by norepinephrine was less in Wistar rat treated with GR water extract than those without GR extract. No significant change in heart rate was observed in SHR receiving either water extract or ethanol extract from GR. Associated with the depressor response, there was a concomitant reduction in plasma levels of norepinephrine in SHR at 4 hour after an oral administration of water extract from GR. Plasma levels of norepinephrine and epinephrine were decreased slightly at 2 hour after an oral administration of ethanol extract from GR. These results suggest that the depressor effect of water extract from GR may be due, in part, to a decreased sympathoadrenal activity.

• The Korean Journal of Physiology
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• v.18 no.2
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• pp.171-180
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• 1984

The death of cattle from acute bracken poisoning has been recognized for many years. Acute bracken poisoning is characterized by mucoidal nasal and anal hemorrhage, severe anorexia. pyrexia, gastric ulcer and myocardial damage. In 1958 Evans first suggested that clinical picture of bracken poisoning was very much similar to that of radiation injuries such as aplastic anemia, leucopenia, thrombocytopenia and increased capillary fragility. Bracken has been clearly demonstrated to contain a carcinogen as well as thiaminase. However, the nature of carcinogen in bracken has not definetely elucidated. Also it was warned by several workers that bracken could be a causative factor for stomach cancer in Korean and Japanese. It appears that little is known on the e(feet of bracken on the function of cardiovascular system. Therefore the present study was designed to explore effects of ethanol extract of raw and toiled bracken (RBEE:BBEE) on blood pressure in cats. Also studied was the mechanism underlying changed in blood pressure of cats by bracken. The result obtained were as follows; 1) Mean arterial blood pressure was invariably decreased following administration of either RBEE or BBEE. Tn general depressor responses to RBEE persisted longer than that to BBEE. Generally, depressor responses were proportional to debases of RBEE and BBEE administered. 2) After administration of 60 mg/kg RBEB and BBEE, blood Pressure decreased by $62.1{\pm}1.7mmHg$ and $68.0{\pm}3.0mmHg$, respectively. No change was observed between depressor responses to RBEE and that to BBEE. 3) Depressor responses to BBEE and RBEE were not affected by vagotomy, propranolol and regitine. 4) In atropinized animal depressor responses to BBEE and RBEE were reduced by 30-40% showing part of depressor response was resulted from cholinergic effect of bracken.

• The Korean Journal of Physiology
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• v.15 no.2
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• pp.91-96
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• 1981

The wormwood is one of the plants which occur widely throughout the world. Though the precise data on the entire chemical composition of mugwort leaves are not available, the major principles which have been found so far include inulin, alkaloid, thujon, sesquiterpene and several vitamins. Santonin, a parasiticide, is one of the glucosides extracted from the limited species of wormwood. It has long been known in herb medicine that the plants of this family has not only strong hemostatic, analgesic and parasiticidal actions but also therapeutic effects for diarrhea, stomachache and asthma. In recent pharmaceutical botany the wormwood is introduced to have antipyretic and astringent actions also. The mugwort(Artemisia asiatica Nakai) is the most common species of wormwood that occurs in Korea. The usage of this edible leaves of mugwort is rather various. It is used not only for wormwood bath but also as forage, moxa and medicinal agents. Recently Kim et al reported from their study on the effect of mugwort on the motility of isolated intestine of rabbits that tonus and motility were markedly enhanced by mugwort but this effect of mugwort on intestinal motility was almost completely blocked by atropine suggesting that activity of mugwort was exerted through its cholinergic effect. It was the findings of Kim et al that prompted the authors to do the present experiment. The present study was undertaken to investigate effects of mugwort(Artemisia asiatica Nakai) juice on the respiration and blood pressure in cats. And also studied was the mechanism of depressor action of Artemisia asiatica Nakai Juice (AAJ). The results obtained are as follows; 1) It was observed that mean arterial blood pressure and heart rate were decreased markedly by AAJ. Following administration of 0.15 ml/kg and 0.3 ml/kg AAJ into cats the maximum depressor responses observed were $77.5{\pm}2.2\;mmHg$ and $94.0{\pm}3.7\;mmHg$ respectively. 2) Depressor responses to AAJ were blocked markedly by atropine whereas the responses were not affected by propranolol and dibenamine. Therefore it is strongly inferred that depressor action of AAJ results mainly from its cholinergic effect. This inference was further substantiated by the fact that heart rate change which invariably accompanies depressor responses to AAJ was almost completely abolished by atropinization. 3) After administration of AAJ into cats frequency of respiration was markedly increased while depth of respiration decreased during first 2-3 seconds.

• The Korean Journal of Pharmacology
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• v.11 no.1 s.17
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• pp.19-26
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• 1975

1. Atropine has recently been known to possess a sympathetic ganglion blocking effect. If atropine blocks the sympathetic ganglia innervating the blood vessels, the drug should cause depressor responses. The author attempted to verify this assumption in urethane-anesthetized rabbits having atropinesterase. 2. Ten and $50{\mu}g/kg$ of atropine produced little variation of the blood pressure; $250{\mu}g/kg$ slight depressor responses; $1,250{\mu}g/kg$ distinct ones. Under hexamethonium-infusion, 10 and $50{\mu}g/kg$ produced observable depressor responses; 250 and $1,250{\mu}g/kg$ produced more pronounced ones. 3. In experiments examining influence of phenoxybenzamine and bretylium on the atropine responses, the lowered blood pressure by these agents was raised by simultaneous infusion of angiotensin with hexamethonium. The depressor responses to atropine (10, 50 and $250{\mu}g/kg$) were slight after the administration of phenoxybenzamine and bretylium. 4. Propranolol did not affect the depressor responses to atropine. 5. In spinalized rabbits the lowered blood pressure was raised by the angiotensin-infusion. In these animals receiving the simultaneous hexamethonium-infusion, atropine (10, 50 and $250{\mu}g/kg$) produced little depressor responses. 6. From these results it is inferred that atropine produced the depressor responses by blocking the sympathetic ganglia innervating the blood vessels.

• YAKHAK HOEJI
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• v.20 no.1
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• pp.83-91
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• 1976

Effects of Alismatis water extract (AE) on the blood pressure were investigated in the rabbit and the dog. AE, when administered into the vein of rabbit and dog, into the lateral ventricle of rbbit, produced fall of blood pressure. The depressor response of the rabbits to intravenous AE was abolished by treatment with atropine, but not with chlorisondamine weakened the depressor effect of AE. Intravenous AE in this rabbit produced secondary elevation of the blood pressure. AE potentiated the pressor response of the rabbit to norepinephrine and tyramine, but nor to angiotensin, acetylcholine, and DMPP.