• The Korean Journal of Physiology and Pharmacology
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• v.2 no.2
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• pp.147-154
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• 1998

It was attempted to clarify the participation of $K^+-channels$ in the post-receptor mechanisms of the muscarinic and $A_1-adenosine$ receptor- mediated control of acetylcholine (ACh) release in the present study. Slices from the rat hippocampus were equilibrated with $[^3H]$choline and the release of the labelled products was evoked by electrical stimulation (3 Hz, 5 V/cm, 2 ms, rectangular pulses), and the influence of various agents on the evoked tritium-outflow was investigated. Oxotremorine (Oxo, $0.1{\sim}10\;{\mu}M$), a muscarinic agonist, and $N^6-cyclopentyladenosine$ (CPA, $1{\sim}30\;{\mu}M$), a specific $A_1-adenosine$ agonist, decreased the ACh release in a dose-dependent manner, without affecting the basal rate of release. 4-aminopyridine (4AP), a specific A-type $K^+-channel$ blocker ($1{\sim}100\;{\mu}M$), increased the evoked ACh release in a dose-related fashion, and the basal rate of release is increased by 3 and $100\;{\mu}M$. Tetraethylammonium (TEA), a non-specific $K^+-channel$ blocker ($0.1{\sim}10\;{\mu}M$), increased the evoked ACh release in a dose-dependent manner without affecting the basal release. The effects of Oxo and CPA were not affected by $3\;{\mu}M$ 4AP co-treatment, but 10 mM TEA significantly inhibited the effects of Oxo and CPA. 4AP ($10\;{\mu}M$)- and TEA (10 mM)-induced increments of evoked ACh release were completely abolished in Ca^{2+}-free$ medium, but these were recoverd in low Ca^{2+}$ medium. And the effects of $K^+-channel$ blockers in low Ca^{2+}$ medium were inhibited by $Mg^{2+}$ (4 mM) and abolished by $0.3\;{\mu}M$ tetrodotoxin (TTX). These results suggest that the changes in TEA-sensitive potassium channel permeability and the consequent limitation of Ca^{2+}$ influx are partly involved in the presynaptic modulation of the evoked ACh-release by muscarinic and $A_1-adenosine$ receptors of the rat hippocampus.

• The Journal of Internal Korean Medicine
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• v.27 no.1
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• pp.92-101
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• 2006

Objectives : This study was done with intend to investigate whether two oriental medical prescriptions, daecheongryong-tang (DCRT) and prescription A (P-A) significantly affect mucin release from cultured hamster tracheal surface epithelial (HTSE) cells. Methods : Confluent HTSE cells were metabolically radiolabeled with $^3H$-glucosamine for 24 hrs and chased for 30 min in the presence of DCRT or P-A to assess the effect of each agent on $^3H$-mucin release. Possible cytotoxicities of each agent were assessed by measuring lactate dehydrogenase (LDH) release. Also, the effects of DCRT and P-A on contractility of isolated tracheal smooth muscle were investigated. Results were as follows : 1. DCRT significantly inhibited mucin release from cultured HTSE cells, with significant cytotoxicity. 2. P-A significantly increased mucin release from cultured HTSE cells, with significant cytotoxicity. 3. DCRT inhibited Ach-induced contraction of isolated tracheal smooth muscle. 4. P-A also inhibited Ach-induced contraction of isolated tracheal smooth muscle. Conclusion: Results suggest that DCRT and P-A have regulating effects on mucin secretion from goblet cells. Further investigation is needed, because of the value in finding novel agents to this purpose, and these oriental medical prescriptions have potential for this role.

• The Journal of Internal Korean Medicine
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• v.27 no.4
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• pp.895-904
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• 2006

Objectives : In the present study, the author intended to investigate whether two oriental medical prescriptions named Socheongryongtang-ga-seoggo (SCTS) and Prescription D (P-D) significantly affect mucin release from cultured hamster tracheal surface epithelial (HTSE) cells. Materials and Methods : Confluent HTSE cells were metabolically radiolabeled with 3H-glucosamine for 24 hrs and chased for 30 min in the presence of SCTS or P-D to assess the effect of each agent on 3H-mucin release. Possible cytotoxicities of each agent were assessed by measuring lactate dehydrogenase (LDH) release. Also, the effects of SCTS and P-D on contractility of isolated tracheal smooth muscle were investigated. Results : SCTS did not affect mucin release from cultured HTSE cells, without cytotoxicity. However, P-D significantly increased mucin release from cultured HTSE cells. with significant cytotoxicity. SCTS inhibited Ach-induced contraction of isolated tracheal smooth muscle. P-D also inhibited Ach-induced contraction of isolated tracheal smooth muscle. Conclusions : The author suggests that the effects of SCTS and P-D with their components should be further investigated and it is valuable to find, from oriental medical prescriptions, novel agents which might regulate mucin secretion from airway goblet cells.

• The Journal of Internal Korean Medicine
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• v.27 no.2
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• pp.295-304
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• 2006

Objectives : This study was done to investigate whether two oriental prescriptions, saganmahwang-tang (SMT) and prescription C (P-C) significantly affect mucin release from cultured hamster tracheal surface epithelial (HTSE) cells. Methods : Cofluent HTSE cells were metabolically radiolabeled with 3H-glucosamine for 24 hrs and chased for 30 min in the presence of SMT or P-C to assess the effect of each agent on 3H-mucin release. Possible cytotoxicities of each agent were assessed by measuring lactate dehydrogenase (LDH) release. Also, the effects of SMT and P-C on contractility of isolated tracheal smooth muscle were investigated. Results : SMT significantly inhibited mucin release from cultured HTSE cells, without cytotoxicity. P-C significantly increased mucin release from cultured HTSE cells, with significant cytotoxicity. SMT inhibited Ach-induced contraction of isolated tracheal smooth muscle. P-C did not affect Ach-induced contraction of isolated tracheal smooth muscle. Conclusion : Results su99est that SMT and P-C have regulating effects on mucin secretion from airway goblet cells. Further investigation is needed, because of the value in finding novel agents to this purpose, and these oriental medical prescription have potential for such a role.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.1
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• pp.29-34
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• 1999

The hyperactivity of cholinergic system in the RVLM of spontaneously hypertensive rats (SHR) may contribute to the sustained elevation of blood pressure. However, the hyperactivity mechanisms of cholinergic system are controversial. Thus, to clarify the mechanisms of cholinergic hyperactivity in RVLM of the SHR, we studied the activities of enzymes that participate in the biosynthesis and degradation of acetylcholine (ACh) and the density of muscarinic receptors in RVLM of the 14- to 18-week-old SHR and age-marched Wistar Kyoto rats (WKY). Choline acetyltransferase activity was far greater in RVLM of SHR than that of WKY. $[^3H]ACh$ release from RVLM was also greater in SHR than in WKY. Acetylcholinesterase activity and $[^3H]NMS$ binding of RVLM slice of SHR were not significantly different from that of WKY. These results suggest that the enhanced cholinergic mechanisms in the RVLM of SHR is due to the enhanced presynaptic cholinergic tone rather than the altered postsynaptic mechanisms.

• The Journal of Pediatrics of Korean Medicine
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• v.20 no.1
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• pp.93-107
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• 2006

Objective : To investigate the effectiveness of two oriental medical prescriptions named Sigoungcheongpyetang(SCPT) and Tonggyutanggamibang(TGT) for mucin release from cultured hamster tracheal surface epithelial(HTSE) cells. Method : Confluent HTSE cells were metabolically radiolabeled with $^{3}H-glucosamine$ for 24hrs and chased for 30 min in the presence of SCPT or TGT to assess the effect of each agent $^{3}H-mucin$ release. Possible cytotoxicities of each agent were assessed by measuring lactate dehy drogenase(LDH) release. Also, the effects of SCPT and TGT on contrectility of isolated tracheal smooth muscle were investigated. Results : (1) SCPT and TGT significantly increased mucin release from cultured HTSE cells, with significantly cytotoxicity ; SCPT did not affect contractility of isolated tracheal smooth muscle and TGT inhibited Ach-induced contraction of isolated tracheal smooth muscle. Conclusion : We suggest that the effects of SCPT and TGT with their components should be further investigated and it is of great value to find, from oriental medical prescriptions, novel agents which might regulate mucin secretion from airway goblet cells.

• The Korean Journal of Physiology
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• v.26 no.1
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• pp.45-54
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• 1992

Effects of pH, $PCO_2$, and adenosine on the vascular contractility were investigated in the pig coronary arteries. The helical strips of isolated coronary arteries were immersed in the HEPES or $HCO_3^-/CO_2$-buffered Tyrode's solution equilibrated with 100% $O_2\;or\;95%\;O_2-5%\;CO_2\;at\;35^{\circ}C$. The contraction was recorded isometrically using a force transducer. The amplitudes of contraction induced by ACh, high $K^+$, and electrical Held stimulation (EFS) were decreased by elevating extracellular pH (pHo) and were increased by lowering pHo. A shift from $0%\;CO_2\;to\;5%\;CO_2$ at constant pHo (pH 7.4) reduced the contractions induced by ACh, high $K^+$, EFS. However the contraction induced by 100mM $K^+$ was less influenced by the change of pHo or $CO_2$. The contraction induced by ACh in $Ca^{2+}$free Tyrode's solution as well as the contraction developed by the addition of extracellular of $Ca^{2+}$ were decreased by lowering pHo and were increased by elevating pHo. High $K^+$ (25mM) induced contraction at pH 6.8 was not returned to the level of the contraction at pH 7.4 by the elevation of extracellular. calcium $[Ca^{2+}]_o$. Adenosine-induced relaxation was more significant with 5% $CO_2$ than 0% $CO_2$ in the high $K^+$-induced contraction and was more significant with low pHo than high pHo in the contraction induced by EFS. From the above results, it is suggested that $H^+$ and $CO_2$ inhibit $Ca^{2+}$ influx as well as $Ca^{2+}$ release from intracellular $Ca^{2+}$ storage sites and enhance the relaxing effect of adenosine in the pig coronary artery.

• The Korean Journal of Physiology and Pharmacology
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• v.11 no.5
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• pp.197-206
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• 2007

The aim of the present study was to investigate the effects of 6-chloro-7,8-dihydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine(SKF81297), a selective agonist of dopaminergic $D_1$ receptor, on the secretion of catecholamines(CA) evoked by cholinergic stimulation and membrane-depolarization in the isolated perfused rat adrenal gland, and also to elucidate the mechanism involved. SKF81297($10{\sim}100{\mu}M$) perfused into an adrenal vein for 60 min produced dose- and time-dependent inhibition of CA secretory responses evoked by ACh(5.32 mM), high $K^+$(56 mM), DMPP($100{\mu}M$) and McN-A-343($100{\mu}M$). Also, in adrenal glands loaded with SKF81297($30{\mu}M$), the CA secretory responses evoked by Bay-K-8644($10{\mu}M$), an activator of L-type $Ca^{2+}$ channels and cyclopiazonic acid($10{\mu}M$), an inhibitor of cytoplasmic $Ca^{2+}$-ATPase were also inhibited. However, in the presence of the dopamine $D_1$ receptor antagonist, (R)-(+)-8-chloro-2,3,4,5-tetrahydro-3-methyl-5-phenyl-1H-benzazepine-7-ol(SCH23390, $3{\mu}M$), which is a selective antagonist of dopaminergic $D_1$ receptor, the inhibitory responses of SKF81297($30{\mu}M$) on the CA secretion evoked by ACh, high $K^+$, DMPP, McN-A-343, Bay-K-8644, and cyclopiazonic acid were significantly reduced. Collectively, these experimental results suggest that SKF81297 inhibits the CA secretion from the rat adrenal medulla evoked by cholinergic stimulation(both nicotininc and muscarinic receptors) and membrane depolarization. This inhibitory of SKF81297 seems to be mediated by stimulation of dopaminergic $D_1$ receptors located on the rat adrenomedullary chromaffin cells, which are relevant to extra- and intracellular calcium mobilization. Therefore, it is thought that the presence of the dopaminergic $D_1$ receptors may be involved in regulation of CA release in the rat adrenal medulla.

• Archives of Pharmacal Research
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• v.24 no.6
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• pp.546-551
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• 2001

We have previously shown that, in circular muscle cells of the lower esophageal sphincter (LES) isolated by enzymatic digestion, contraction in response to maximally effective doses of acetylcholine (ACh) or Inositol Triphosphate ($IP_3$) depends on the release of $Ca^{2+}$ from intracellular stores and activation of a $Ca6{2+}$-calmodulin (CaM)-dependent pathway. On the contrary, maintenance of LES tone, and response to low doses of ACh or $IP_3$ depend on a protein kinase C (PKC) mediated pathway. In the present investigation, we have examined requirements for $Ca6{2+}$ regulation of the interaction between CaM- and PKC-dependent pathways in LES contraction. Thapsigargin (TG) treatment for 30 min dose dependently reduced ACh-induced contraction of permeable LES cells in free $Ca6{2+}$ medium. ACh-induced contraction following the low level of reduction of $Ca6{2+}$ stores by a low dose of TG ($10^{-9}{\;}M$) was blocked by the CaM antagonist, CCS9343B but not by the PKC antagonists chelerythrine or H7, indicating that the contraction is CaM-dependent. After maximal reduction in intracellular $Ca{2+}$ from $Ca6{2+}$stores by TG ($10^{-6}{\;}M$), ACh-induced contraction was blocked by chelerythrine or H7, but not by CCS9343B, indicating that it is PKC-dependent. In normal $Ca^{2+}$medium, the contraction by ACh after TG ($10^{-9}{\;}M$) treatment was also CaM-dependent, whereas the contraction by ACh after TG ($10^{-9}{\;}M$) treatment was PKC-dependent. We examined whether PKC activation was inhibited by activated CaM. CCS 7343B Inhibited the CaM-induced contraction, but did not inhibit the DAC-induced contraction. CaM inhibited the DAC-induced contraction in the presence of CCS 9343B. This inhibition by CaM was $Ca{2+}$dependent. These data are consistent with the view that the switch from a PKC-dependent pathway to a CaM dependent pathway can occur and can be regulated by cytosolic $Ca{2+}$ in the LES.

• The Korean Journal of Pharmacology
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• v.32 no.1
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• pp.67-74
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• 1996

Cholecystokinin octapeptide (CCK-8), acetylcholine (ACh) and KCl caused a dose dependent contraction in muscle cells enzymatically digested from cat gallbladder. Maximal contraction was obtained at concentration of $10^{-9}M$ for CCK-8, $10^{-5}M$ for ACh and 20mM for KCl. CCK-8 induced contraction was unaffected in calcium free physiological salt solution (PSS) and was completely blocked by strontium substitution for calcium (p<0.001). In contrast, KCl evoked contraction was blocked in calcium free PSS (p<0.01) but was unaffected by strontium replacement of calcium. The contraction elicited by ACh was only slightly reduced in calcium free PSS (p<0.05) and was unaltered by strontium. Muscle cells permeabilized with saponin contracted in response to inositol 1,4.5-trisphosphate $(IP_3)$ and CCK-8. The contraction was blocked by the calmodulin antagonist CGS 9343B (p<0.001), whereas heparin completely blocked the effect of $IP_3$ (p<0.001). The protein kinase C (PKC) antagonist H7 had no effect on either agonist. We conclude that CCK-8 induced gallbladder muscle contraction is mediated by $IP_3$ dependent intracellular calcium release from intracellular stores and a calmodulin dependent pathway; ACh may utilize both extracellular and intracellular calcium. KCl causes muscle contracrion through influx of extracellular calcium and a calmodulin independent machanism.