• 약학회지
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• 제56권3호
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• pp.180-185
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• 2012

The aim of present study was to investigate the possible influence and related mechanism of alcohol on the arterial contraction. Vascular contraction involves the activation of thick or thin filament pathway. However, there are no reports addressing the question whether this pathway is involved in alcohol-induced regulation. We hypothesized that alcohol plays a role in vascular contraction evoked by a vasoconstrictor in rat aortae regardless of endothelial function. Denuded arterial rings from male rats were used and isometric contractions were recorded using a computerized data acquisition system. Interestingly, alcohol at a low concentration (3% v/v) inhibited thromboxane $A_2$ or phorbol ester-induced contraction with endothelial function but at a high concentration (10%) didn't inhibit and rather increased the contraction in the denuded muscle. Therefore, alcohol at a low concentration decreases the contraction and alcohol at a high concentration increases the contraction suggesting that additional pathways different from endothelial nitric oxide synthesis might be involved in the regulation of contractility. In conclusion, alcohol has some effect on the regulation of contractility regardless of endothelial function.

• Biomolecules & Therapeutics
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• 제3권2호
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• pp.143-148
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• 1995

Recently, we reported that GS 389 has vasodilating action without cardiac inotropic action (Chang et al., Can. J. Physiol. Pharmacol. 72, 327-334, 1994). However the mechanism of action of GS 389 has not been thoroughly evaluated. In the present study, we performed functional study of GS 389 in rat trachealis, thoracic aorta, pig coronary artery by isometric tension and in human platelets by aggregation experiments. We also tested if GS 389 influences on $Ca^{2+}$movement and inositol phosphate metabolism. In rat trachealis, GS 389 concentration-dependently relaxed carbachol (0.1 $\mu$M)- and high $K^{+}$(65.4 mM)-induced contraction with p$IC_{50}$/ of 4.43$\pm$ 0.19 and 4.11$\pm$0.12, respectively. In $Ca^{2+}$-free media, GS 389 inhibited carbachol-induced phasic contraction. In rat thoracic aorta, GS 389 inhibited $^{45}$ Ca uptake due to norepinephrine and high $K^{+}$, indicating that GS 389 has direct inhibitory action of $Ca^{2+}$movement. Furthermore, GS 389 competitively inhibited U46619-induced contraction in rat thoracic aorta and pig coronary artery with K, values of 5.23$\pm$0.12 and 5.56$\pm$0.14, respectively, and inhibited U 46619-induced phosphatidylinositide (PI) turnover in rat aorta. GS 389 also concentration-dependently inhibited the human platelet aggregation against U 46619 with p$IC_{50}$/ 5.66$\pm$0.02. These results indicate that GS 389 has thromboxane $A_2$ antagonistic action in vascular and platelets as well as direct action on $Ca^{2+}$ movement, which may account, at least in part, for relaxing action of rat trachealis. trachealis.

• 대한약리학회지
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• 제20권1호
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• pp.41-46
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• 1984

카드뮴중독으로 혈소판응집이 항진되어 고혈압 또는 동맥경화증이 발생한다는 연구보고를 감안하여 가토와 흰쥐의 생체내 실험으로서 미세혈전의 형성, Malondialdehyde(MDA) 및 thromboxane $B_2(TXB_2)$치에 미치는 카드뮴의 효과를 검토하고, in vitro실험으로 카드뮴을 처치한 가토 대동맥절편이 혈소판응집에 미치는 영향을 관찰하였으며, prostacyclin의 합성능력을 측정하여 그 결과를 다음과 같이 요약하였다. 1)Cadmium chloride 2mg/kg을 매주 동물의 복강내에 주입하였을 때 미세혈전형성이 증가되었다. 2) 카드뮴 중독동물의 platelet-rich plasma (PRP)는 MDA와 $TXB_2$형성이 정상동물에서 보다 현저히 증가되었다. 3) 카드뮴을 중독시킨 가토의 platelet-poor plasma (PPP)에서의 lipid peroxide치는 대조군과 차이가 없었다. 4) In vitro 실험으로, 가토대동맥 절편에서의 6-keto-$PGF_{1{\alpha}}$의 생성은 카드뮴 농도에 비례하여 억제되었고 이때 혈소판 응집률의 증가와 평행하였다. 5) 이상의 결과로서 카드뮴은 동맥내피세포에서 prostacyclin 합성을 억제할 뿐만 아니라 혈소판에서 $TXA_2$합성을 촉진시켜 그 결과로 혈소판 응집률을 증가시켰음을 알 수 있었다.

• 한국산학기술학회논문지
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• 제20권12호
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• pp.298-305
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• 2019

꾸지뽕나무 뿌리 추출물은 항염, 항암, 항산화와 같은 효과를 갖는 많은 생리활성 물질을 포함하고 있다고 알려져 있다. 그러나 꾸지뽕나무 뿌리 추출물(이하 CTE)의 사람 혈소판 응집 억제 기전에 관하여는 알려진 바 없다. 본 연구에서는 CTE가 혈소판에 미치는 영향을 확인하고자 하였다. CTE는 collagen으로 유도한 혈소판 응집 반응에서 cyclooxygenase-1 활성을 억제하고, 세포 내 칼슘 농도를 낮추는 방식으로 thromboxane A₂ 생성을 억제하였다. 또한, phospholipase Cγ2와 syk의 인산화 반응을 억제하였으며, guanosine monophosphate (cGMP)에 의존적인 방식으로 vasodilator-stimulated phosphoprotein(VASP)의 Ser²³⁹ 위치를 인산화하여 항혈소판 효과를 나타내었다. 또한, 고지방 식이로 혈소판 활성화를 유도한 랫드에서 CTE를 경구 투여 하였을 때, 간독성 없이 콜라겐으로 유도한 혈소판 응집반응을 thromboxane A₂ 생성을 억제함으로써 항혈소판 효과를 보였다. 이는 in vivo와 in vitro에서 같은 결과를 제시하고 있다. 결론적으로, CTE는 항혈소판 작용 및 심혈관계 질환 예방을 위한 천연물 유래의 안전하고, 새로운 물질임을 제시하는 바이다.

• Journal of Chest Surgery
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• 제23권2호
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• pp.222-230
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• 1990

Protamine, a polycationic peptide extracted from fish, has been widely used for the reversal of anticoagulant action of heparin. However it may cause untoward circulatory side effects including hypotension and bradyarrhythmia. Nowadays, histamine and prostacyclin are regarded as one of the causative agents in the underlying mechanism of hemodynamic changes. To certify the possible role of histamine and prostacyclin, we observed simultaneous changes of the hemodynamic status, plasma concentration of thromboxane B, and circulating platelet count before and after intravenous injection of protamine. Experimental dogs, weighing 12-14kg, were divided into 2 groups; group A animals [n=10], were pretreated with indomethacin[2.5mg/kg] and group B animals[n=10] were pretreated with chlorpheniramine[0.5mg/kg] Heparin[3mg/kg] and protamine [3mg/kg] were administered sequentially in both groups. The results were as follows ; 1. The mean systemic arterial pressure was maintained well in groups A, whereas in group B it decreased from 165\ulcorner18mmHg to 138\ulcorner30mmHg[p<0.01] and 151\ulcorner21 mmHg[p<0.05] at 1 minute and 2 minutes after protamine injection. The mean pulmonary arterial pressure was not changed significantly in group A, whereas in group B it increased from 852 mmHg to 11\ulcorner3 mmHg[p<0.05], 11\ulcorner3 mmHg[p<0.05] and 10\ulcorner3 mmHg[p<0.05] at 1 minute, 3 minutes and 5 minutes after protamine injection. 2 The thromboxane B2 was not changed significantly in group A, whereas in group B it increased from 399\ulcorner401 \ulcornerg/ml to 744\ulcorner615 \ulcornerg/ml[p<0.05] and 814\ulcorner1070 \ulcornerg/ml [p<0.0 5] at 1 minute and 3 minutes after protamine injection without concomitant changes of pulmonary vascular resistance and pulmonary capillary wedge pressure. 3. The number of circulating platelet was not changed in group A, whereas in group B it decreased from 207100\ulcorner103600/\ulcornerl to 159700\ulcorner90900/\ulcornerl [p<0.05] at 1 minute after protamine injection, Although thromboxane B2 and platelet count were changed significantly after protamine injection, they did not cause the remarkable hemodynamic changes. Considering the above results, hemodynamic changes may be caused mainly by prostacyclin rather than thromboxane or platelet. Therefore, the pretreatment with cyclooxygenase inhibitor would be beneficial to prevent circulatory adverse effects of protamine for the patients undergoing cardiac surgery.

• Biomolecules & Therapeutics
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• 제21권1호
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• pp.54-59
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• 2013

In this study, we investigated the effect of (-)-epigallocatechin-3-gallate (EGCG), a major component of green tea catechins from green tea leaves, on activities of cyclooxygenase (COX)-1 and thromboxane synthase (TXAS), thromboxane $A_2$ ($TXA_2$) production associated microsomal enzymes. EGCG inhibited COX-1 activity to 96.9%, and TXAS activity to 20% in platelet microsomal fraction having cytochrome c reductase (an endoplasmic reticulum marker enzyme) activity and expressing COX-1 (70 kDa) and TXAS (58 kDa) proteins. The inhibitory ratio of COX-1 to TXAS by EGCG was 4.8. These results mean that EGCG has a stronger selectivity in COX-1 inhibition than TXAS inhibition. In special, a nonsteroid anti-inflammatory drug aspirin, a COX-1 inhibitor, inhibited COX-1 activity by 11.3% at the same concentration ($50{\mu}M$) as EGCG that inhibited COX-1 activity to 96.9% as compared with that of control. This suggests that EGCG has a stronger effect than that of aspirin on inhibition of COX-1 activity. Accordingly, we demonstrate that EGCG might be used as a crucial tool for a strong negative regulator of COX-1/$TXA_2$ signaling pathway to inhibit thrombotic disease-associated platelet aggregation.

• Journal of Nutrition and Health
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• 제32권4호
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• pp.384-393
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• 1999

The degree of platelet aggregation, thromboxane B2(TXB2)formation and fatty acid composition of platelet phospholipids(PL) were investigated in 24 healthy male subjects who for five weeks consumed either corn oil(CO) rich in linoleic acid(LA), perilla oil (PO) rich in $\alpha$-linoleic acid($\alpha$-LAN), or canola oil(CNO) rich in oleic acid(OA) as a major fat source. Total fat intake was 30% of total calories and prescribed oil intake of each dietary group was 50% of the total fat intake. In the CO group, significantly decreased contents of polyunsaturated fatty acids(PUFA), n-6 PUFA, n-3 PUFA and eicosapentanoic acid(EPA) were observed, and significantly increased contents of OA and saturated fatty acids(SFA) were observed in platelet PL after 3 weeks and 5 weeks of dietary treatment. In the PO group, contents of OA and docosahexanoic acid(DHA) were increased, and the ratio of n-6/n-3 was decreased significantly in platelet PL after dietary treatment. The CNO group showed significatnlty decreased contents of PUFA, P/S ratio, n-6 PUFA, LA,(EPA+DHA)/arachidonic acid(AA), and significantly increased SFA contents after 3 weeks of the oil-based diet. The dietary-induced effects on fatty acid composition of platelet PL were observed mostly after 3 weeks of the oil-based diet. The dietary-induced effects on fatty acid composition of platelet PL were observed mostly after 3 weeks. Plasma TXB2 levels were increased after 3 and 5 weeks of dietary treatment. However, only the CO and CNO groups showed significantly increased plasma TXB2 levles after 3 and 5 weeks of dietary treatment. However, only the CO and CNO groups showed significantly increased plasma TXB2 levels after 5 weeks of experimental diets, when compared with initial values. Degree of platelet aggregation increased only in the CO group after dietary treatment. As a result, at week 5 the degree of platelet aggregation of the CO group was significantly higher than those of the PO and CNO groups. Among the three oil-based diets, the PO-based diet seems to have beneficial effects on atherosclerosis by influencing plasma TXB2 levels and the degree of platelet aggregation, while the CO-based diet showed the most adverse effects. Our results imply that plasma TXB2 levels might be affected by dietary fatty acid composition.

• Biomolecules & Therapeutics
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• 제3권2호
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• pp.104-110
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• 1995

Arachidonic acid (AA, C20 : 4, $\omega$-6) and eicosapentanoic acid (EPA,C20 : 5, $\omega$-3), which are polyunsaturated fatty acids forming eicosanoids, were tested for their effects on blood pressure in Wistar rats and SHR. AA is the most important precursor for the biosynthesis of eicosanoids which include the prostaglandins, prostacyclin (PGI$_2$), thromboxane $A_2$ (TXA$_2$) and the leukotriens. TXA$_2$is a potent vasoconstrictor and a powerful inducer of platelet aggregation causing myocardial infarction and hypertention. In contrast, PGI$_2$ induces vasodilation and inhibits platelet aggregation. In this study, AA markedly increased blood pressure, but its effect was antagonized by both EPA, a structural analog of AA, and dazmegrel, a TX synthetase inhibitor. Also, AA enhanced the antihypertensive effects of hydralazine and captopril, and EPA reduced TXA$_2$ production. These results indicate that the hypotensive effects of EPA might be closely related to the decrease in TXA$_2$ biosynthesis due to competitive inhibition by structural similarity of the EPA to the AA, the precursor of TXA$_2$.

• Journal of Applied Biological Chemistry
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• 제65권4호
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• pp.463-469
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• 2022

Cudrania tricuspidata (C. tricuspidata), a medicinal plant widely employed throughout Asia in ethnomedicine, has various bioactive properties, including antidiabetic, antiobesity, antitumor, and anti-inflammatory activities. In addition, the C. tricuspidata root extract reportedly inhibits platelet aggregation. Therefore, we focused on the active substances present in the C. tricuspidata extract. Sanggenon N (SN) is a flavonoid found in the root bark of C. tricuspidata. In the present study, we examined the inhibitory effects of SN on platelet aggregation, phosphoproteins, thromboxane A₂ generation, and integrin αIIbβ3 activity. SN inhibited collagen-induced human platelet aggregation in a dose-dependent manner without cytotoxicity. Furthermore, SN suppressed Ca²⁺ mobilization and influx through associated signaling molecules, such as inositol 1, 4, 5-triphosphate receptor I (Ser¹⁷⁵⁶), and extracellular signal-regulated kinase. In addition, SN inhibited thromboxane A₂ generation and associated signaling molecules, including cytosolic phospholipase A₂ and mitogen-activated protein kinase p38. Finally, SN could inhibit integrin (αIIb/β₃) activity by regulating vasodilator-stimulated phosphoprotein and Akt. Collectively, SN possesses potent antiplatelet effects and is a potential therapeutic drug candidate to prevent platelet-related thrombosis and cardiovascular disease.

• The Korean Journal of Physiology and Pharmacology
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• 제16권1호
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• pp.59-64
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• 2012

Hypoxic pulmonary vasoconstriction (HPV) is physiologically important response for preventing mismatching between ventilation and perfusion in lungs. The HPV of isolated pulmonary arteries (HPV-PA) usually require a partial pretone by thromboxane agonist (U46619). Because the HPV of ventilated/perfused lungs (HPV-lung) can be triggered without pretone conditioning, we suspected that a putative tissue factor might be responsible for the pretone of HPV. Here we investigated whether HPV can be also observed in precision-cut lung slices (PCLS) from rats. The HPV in PCLS also required partial contraction by U46619. In addition, $K^+$ channel blockers (4AP and TEA) required U46619-pretone to induce significant contraction of PA in PCLS. In contrast, the airways in PCLS showed reversible contraction in response to the $K^+$ channel blockers without pretone conditioning. Also, the airways showed no hypoxic constriction but a relaxation under the partial pretone by U46619. The airways in PCLS showed reliable, concentration-dependent contraction by metacholine ($EC_{50}$, ~210 nM). In summary, the HPV in PCLS is more similar to isolated PA than V/P lungs. The metacholineinduced constriction of bronchioles suggested that the PLCS might be also useful for studying airway physiology in situ.