• YAKHAK HOEJI
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• v.45 no.3
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• pp.282-286
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• 2001

To investigate the different mechanism between ATP and compound 48/80 (C$_{48}$80/)-induced histamine release, we observed effects of calcium antagonists in histamine release of rat peritoneal mast cells. Verapamil and diltiazem (voltage-dependent calcium channel blocker) and TMB-8 (a blocker of intracellular calcium release) significantly inhibited ATP-induced histamine release, but did not inhibit $C_{48}$80/-induced histamine release. Econazole (a blocker of receptor-operated calcium channel) dose-dependently inhibited both ATP and $C_{48}$80/-induced histamine release, but inhibitory effect of econazole in ATP-induced histamine release was more potent than that in $C_{48}$80/-induced histamine. EGTA dose-dependently inhibited ATP and $C_{48}$80/-induced histamine release, but $C_{48}$80/-induced histamine release was slightly inhibited by high concentrations (>2 mM) of EGTA. These results suggest that ATP-induced histamine release is related to broth intracellular calcium release and extracellular calcium influx via voltage-dependent calcium channel and receptor-operated calcium channel. $C_{48}$80/-induced histamine release is related to extracellular calcium influx, especially by receptor-operated calcium channel rather than voltage-dependent calcium channel.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.552-556
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• 2001

Histamine and arachidonic acid (AA) release was measured using the P2-purinoceptor antaongists, phospholipase $A_2{\;}(PLA_2)$ and cyclooxygenase (COX)/lipoxygenase (LOX) inhibitors to determine whether or not ATP-induced histamine release is associated with arachidonic acid (AA) release in rat peritoneal mast cells. ATP increased histamine release in a dose dependent manner, whereas adenosine did not. PPADS (a selective P2X-purinoceptor antagonist) and suramin (a nonselective P2X,2Y-purinoceptor antagonist) inhibited ATP-induced histamine release in a dose dependent manner. However, RB-2 (a P2Y-purinoceptor antagonist) did not block ATP-induced histamine release. Manoalide and oleyloxyethyl phosphorylcholine (OPC), secretory PLA$_2$ inhibitors, also inhibited ATP-induced histamine release dose-dependently. Both COX inhibitors (ibuprofen and indomethacin) and LOX inhibitors (baicalein and caffeic acid) inhibited ATP-induced histamine in a dose dependent manner. ATP significantly increased [$^3H$]AA release by 54%. PPADS and suramin significantly inhibited ATP-induced [3H]Ph release by 81% and 39%, respectively. ATP-induced histamine release was significantly inhibited by a variety of protein kinase inhibitors, such as bisindolmaleimide, genistein, methyl 2,5-dihydroxycinnamate, W-7 and trifluoperazine. Overall, the results suggest that ATP-induced histamine release is in part related to the PLA2-mediated AA metabolism and P2X-purinoceptors.

• YAKHAK HOEJI
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• v.45 no.3
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• pp.287-292
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• 2001

To investigate whether phospholipase $A_2$pathway is involved in histamine release of rat peritoneal mast cells, we measured histamine release in the presence of various enzyme inhibitors involved in eicosanoid pathway, such as phospholipase $A_2$, cyclooxygenase and lipoxygenase. Phospholipase $A_2$inhibitors, manoalide and OPC, significantly inhibited histamine release induced by 100 $\mu$M ATP and 1$\mu$g/ml compound 48/80. Cyclooxygenase inhibitors, ibuprofen and indomethacin, significantly inhibited ATP-induced histamine release and lipoxygenase inhibitors, baicalein and caffeic acid, also significantly inhibited. To investigate the involvement of protein kinase in ATP- and compound 48/80-induced histamine release, we observed effects of protein kinase inhibitors on histamine release. Bisindolmaleimide (protein kinase C antagonist) dose-dependently inhibited both ATP and compound 48/80-induced histamine release. Tyrosine kinase inhibitors (methyl 2,5-dihydroxy cinnamate and genistein) dose-dependently inhibited ATP and compound 48/80-induced histamine release. Protein kinase C and tyrosine kinase seem to be involved in histamine release induced by ATP and compound 48/80. These results suggest that phospholipase $A_2$pathway as well as protein kinase C and tyrosine kinase are involved in histamine release of rat peritoneal mast cells by ATP and compound 48/80.

• Korean Journal of Veterinary Research
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• v.36 no.4
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• pp.887-894
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• 1996

Cyclopiazonic acid(CPA) known as stimulating the release of intracellular calcium, aflatoxin $B_1(AFB_1)$ causing gastrointestinal hemorrhage frequently were used as model toxic mycotoxins in these studies. First of all, the effects of various mycotoxins on the platelet aggregation response were determined. The effects of mycotoxins on the ATP release from platelet by aggregating factors were investigated. The results and conclusions obtained from these studies are : 1) CPA promoted ADP, collagen, thrombin, A.A. and PAF-induced rabbit platelet aggregation. $AFB_1$ inhibited collagen, A.A. and PAF-induced rabbit platelet aggregation only. 2) CPA increased both aggregation and disaggregation time, whereas $AFB_1$ decreased in a dose dependent manner. 3) CPA increased ADP, thrombin, A.A. and PAF-induced ATP release. $AFB_1$ increased A.A.-induced ATP release and decreased PAF-induced release in a dose dependent manner. In conclusion, CPA promoted platelet aggregation by the increase of ATP. Antiaggregating effects of AFB1 may be due to decreases of ATP. These data provide the basis for the future study of roles of ATP release in platelet aggregation.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1996.04a
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• pp.219-219
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• 1996

Mucin release from hamster tracheal surface epithelial(HTSE) cells can be stimulated by extracellular ATP via activation of P$_2$ purinoceptors located on the cell surface which appears to be coupled to phospholipase C via G proteins. However, our preliminary data indicate that the ATP-induced mucin release involves, in part, activation of PKC, but not an increase in the intracellular Ca++ level, suggesting the presence of another pathway which is separate from the PLC-PKC pathway, In this study, we intended to confirm the previous observation and subsequently identify an additional mechanism. Confluent HTSE cells were metabolically labeled with either $^3$H-glucosamine or $^3$H-arachidonic acid(AA), and release of either $^3$H-mucin or $^3$H-AA was quantified following various treatments. $^3$H-mucin was assayed using the sepharose CL-4B gel-filtration method, whereas $^3$H-AA liberation was measured by counting $^3$H-radioactivity in the chase medium. We found that: (1)Desensitization of PKC by pretreatment with PMA completely abolished the mucin releasing effect of PMA but partially inhibited the ATP-induced mucin release; (2) ATP increases release of $^3$H-AA in a dose-dependent fashion; (3) mepacrine, an inhibitor of PLA$_2$, attenuates ATP-induced mucin release in a dose-dependent fashion. These results confirm our previous notion that the PLC-PKC pathway is responsible, in part, for ATP-induced mucin release. Furthermore, activation of PLA$_2$ appears to be an additional pathway which is involved in ATP-induced mucin release.

• The Korean Journal of Pharmacology
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• v.29 no.1
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• pp.9-22
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• 1993

To evaluate the protective effects of calcium antagonists, oxygen radical scavengers and excitatory amino acid (EAA) antagonist on the ischemic brain damage, we induced in vitro ischemic condition (namely, lack of oxygen and glucose) to rat hippocampal slices. And the degree of ischemic damage was determined by assaying changes in biochemical parameters such as ATP content and lactate ralease, MDA production in the presence or absence of the various drugs. During experimental ischemia for up to 60 min, ATP content was decreased and the amount of lactate release was markedly increased time-dependently. By changing the reaction medium which contained oxygen and glucose those biochemical parameters were recovered. But the recovery was not complete in this experimental condition. In the same ischemic conditions verapamil and vitamine E prevented the decrease of ATP content and the increase of lactate release from the slices. And verapamil and diltiazem decreased MDA release to the reaction medium. Superoxide dismutase (SOD) and MK-801 (as EAA receptor antagonist) protected the decrease of ATP content and reduced MDA release in 20 min ischemic condition, but glutathione affected ATP content and lactate release at the same condition. When oxygen and glucose were resupplied for 20 min after ischemic condition, verapamil showed the protective effect on the changes of ATP content and lactate release, and vitamine E decreased lactate release (at 20 min ischemia) and MDA release (at 60 min ischemia). These results showed that calcium antagonist and vitamine E protect the ischemic biochemical changes from rat hippocampal slices and calcium antagonist is more potent than vitamine E to protect the ischemical brain damege.

• YAKHAK HOEJI
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• v.45 no.6
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• pp.677-682
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• 2001

investigate action of ethanol on histamine release from rat peritoneal mast cells, we compared the inhibitory effect of ethanol with those of calcium antagonists in mechanism of between ATP and compound 48/80-induced histamine release. Ethanol dose-dependently inhibited 100 ${\mu}{\textrm}{m}$ ATP-induced histamine release, whereas did not inhibit 1 $\mu\textrm{g}$/ml compound 48/80-induced histamine release. Verapamil, TMB-8 and EGTA dose-dependently inhibited ATP-induced histamine release, but did not inhibit compound 48/80-induced histamine release. Such an inhibitory effect of calcium antagonist was similar to that of ethanol. These results suggest that the inhibitory effect of ethanol on histamine release from rat peritoneal mast cells is mediated via disturbance of calcium mobilization..

• Biomolecules & Therapeutics
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• v.10 no.3
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• pp.156-164
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• 2002

In the present study, we tried to investigate whether polymerized basic amino acid e.g. poly-L-lysine (PLL) which has the degree of polymerization under 50mer significantly affects the physiological and stimulated mucin release from cultured hamster tracheal surface epithelial cells. Confluent primary hamster tracheal surface epithelial (HTSE) cells were metabolically radiolabeled with $^3{H}$-glucosamine for 24 hr and chased for 30 min in the presence of either PLLs or adenosine triphosphate (ATP) and PLL to assess the effects on basic or ATP-stimulated $^3{H}$-mucin release. Possible cytotoxicities of PLLs were assessed by measuring lactate dehydrogenase (LDH) release from HTSE cel1s during treatment. The results were as follows: PLLs significantly inhibited basic mucin release from cultured HTSE cells in a dose-dependent manner from the range of 46mer to 14mer; PLL 46mer significantly inhibited the stimulated mucin release by ATP from cultured HTSE cells; there was no significant release of LDH from cultured HTSE cells during treatment. We conclude that PLLs inhibit both physiological and stimulated mucin release from airway epithelial cells without significant cytotoxicity and PLL lost its activity under the range of 14mer. This finding suggests that polymer of basic amino acid like PLL might function as a regulator for hypersecretion of mucus manifested in various respiratory diseases.

• Toxicological Research
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• v.14 no.3
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• pp.333-339
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• 1998

Sambutoxin, a newly purified mycotoxin in Koea, caused hemorrhage in the stomach and intestine of rats. To elucidate the mechanism of hemorrhage, effects of sambutoxin on rabbit platelet aggregation were investigated. First of all, the effects of sambutoxin on the platelet aggregation response and ATP release from platelet by various appregating factors were investigated. And then the role of $Ca^{2+}$ on the platelet aggregation was investigated by flow cytometer. Finally, morphological effect of sambutoxin on platelet ultrastructure was examined by transmission electron microscope. Sambutoxin inhibited aggregation induced by ADP, collagen, thrombin, and arachidonic acid and decreased platelet activating factor-induced disaggregation time in a dose dependent manner. Sambutoxin also decreased thrombin and arachidonic acid-induced ATP release, but increased all factors induced $Ca^{2+}$ release. Sambutoxin showed severe ultrastructural changes of platelet such as appearance of disorganization debri of cellular organelle in intercellular space. Our results indicate that sambutoxin inhibitis rabbit platelet aggregation, and it may be party due to the decrease of ATP release. However, it is not clear whether the antiaggregating effect of sambutoxin is related to $Ca^{2+}$ increase.

• Korean Journal of Clinical Pharmacy
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• v.5 no.2
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• pp.75-84
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• 1995

Drug delivery by red cells was established to maintain the release of drugs in the blood. The entrapment method by amphotericin B was re-examined and evaluated for obtaining the suitable entrapping conditions without hemolysis. The amphotericin B treatment below $10{\mu}g/ml$ induced the non-hemolysis to entrap daunorubicin into red cells within 10min. Under these conditions intracellular ATP level was decreased as $18\%$. Membrane fluidity and the shape factor of red cells were maintained. To maintain intracellular ATP, ATP and sodium pyruvate were added during the entrapment procedure because hemolysis during the release test would reflect the loss of intracellular ATP that would be postulate the decrease of the viability invivo. Consequently, the addition of ATP in the reaction solution can raise the intracellular level of ATP.