• 한국응용약물학회:학술대회논문집
• /
• 한국응용약물학회 2001년도 추계학술대회 및 정기총회
• /
• pp.95-95
• /
• 2001

Ciinidipine (FRC-8635) is a newly synthesized novel DHP type of organic Ca$\_$2＋/channel blockers that have been developed so far in Japan (Yoshimoto et al., 1991 : Hosono et at., 1992). It also has a blocking action on L-type voltage-dependent Ca$\^$2＋/channel (VDCCs) in the rabbit basilar artery (Oike et al., 1990) and a slow-onset and long-lasting hypotensive action in clinical and experimental studies (Ikeda et al., 1992 ; Tominaga et al., 1997). Recent electrophysiological data indicate that cilnidipine might be a dual-channel antagonist for peripheral neuronal N-type and vascular L-type Ca$\^$2＋/channels (Oike et al., 1990 ; Fujii et al., 1997; Uneyama et at., 1997). However, little is known about the involvement of N-type VDCCs in contributing to the muscarinic receptor-mediated CA secretion. Therefore, the present study was attempted to investigate the effect of cilinidipine on secretion of catecholamines (CA) evoked by ACh, high K$\^$＋/, DMPP and McN-A-343 from the isolated perfused rat adrenal gland. Cilnidipine (1-10 ${\mu}$M) perfused into an adrenal vein for 60 min produced dose- and time-dependent inhibition in CA secretory responses evoked by ACh (5.32${\times}$10$\^$-3/M), DMPP (10$\^$-4/ M for 2 min) and McN-A-343 (10$\^$-4/ M for 2 min). However, lower dose of lobeline did not affect CA secretion by high K$\^$＋/(5.6${\times}$10$\^$-2/ M), higher dose of it reduced greatly CA secretion of high K$\^$＋/. Cilnidipine itself did also fail to affect basal catecholamine output. Furthermore, in adrenal glands loaded with cilnidipine (10 ${\mu}$M), CA secretory response evoked by Bay-K-8644 (10 ${\mu}$M), an activator of L-type Ca$\^$2＋/channels was markedly inhibited while CA secretion by cyclopiazonic acid (10 ${\mu}$M), an inhibitor of cytoplasmic Ca$\^$2＋/-ATPase was no affected. Moreover, $\omega$-conotoxin GVIA (1 ${\mu}$M), given into the adrenal gland for 60 min, also inhibited time-dependently CA secretory responses evoked by ACh and high K$\^$＋/.

• Biomolecules & Therapeutics
• /
• 제10권3호
• /
• pp.142-151
• /
• 2002

The present study was attempted to investigate the effect of apamin on catecholamine (CA) secretion evoked by ACh, high $K^+$, DMPP, McN-A-343, cyclopiazonic acid and Bay-K-8644 from the isolated perfused rat adrenal gland and to establish the mechanism of its action. The perfusion of apamin (1 nM) into an adrenal vein for 20 min produced greatly potentiation in CA secretion evoked by ACh (5.32 $ imes$ $10^{-3}$ M), high $K^+$, (5.6 $ imes$ $10^{-2}$), DMPP ($10^{-4}$ M for 2 min), McN-A-343 ($10^{-4}$ M for 2 min), cyclopiazonic acid ($10^{-5}$ M for 4 min) and Bay-K-8644 ($10^{-5}$ M for 4 min). However, apamin itself did fail to affect basal catecholamine output. Furthermore, in adrenal glands preloaded with apamin (1 nM) under the presence of glibenclamide ($10^{-6}$ M), an antidiabetic sulfonylurea that has been shown to be a specific blocker of ATP-regulated potassium channels (for 20 min), CA secretion evoked by DMPP and McN-A-343 was not affected. However, the perfusion of high concentration of apamin (100 nM) into an adrenal vein for 20 min rather inhibited significantly CA secretory responses evoked by ACh, high $K^+$, DMPP, McN-A-343, cyclopiazonic acid and Bay-K-8644. Taken together, these results suggest that the low concentration of apamin causes greatly the enhancement of CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as by membrane depolarization. These findings suggests that apamin-sensitive SK ($Ca^{2+}$) channels located in rat adrenal medullary chromaffin cells may play an inhibitory role in the release of catecholamines mediated by stimulation of cholinergic nicotinic and muscarinic receptors as well as membrane depolarization. However, it is thought that high concentration of apamin cause the inhibitory responses in catecholamine secretion evoked by stimulation of cholinergic receptors as well as by membrane depolarization from the rat adrenal gland without relevance with the SK channel blockade.

• Archives of Pharmacal Research
• /
• 제24권3호
• /
• pp.240-248
• /
• 2001

The present study was attempted to investigate the effect of quinine on secretion of catecholamines (CA) etroked by cholinergic stimulation and membrane depolarization from the isolated perfused rat adrenal gland. The perfusion of quinine (15-150${\mu}$M) into an adrenal vein for 60 min produced dose- and time-dependent inhibition in CA secretion evoked by ACh ($5.32{\times}10^{-3}M$), high $K^{+}5.6{\times}10^{-2}M$, DMPP ($10^{-4}M$ for 2 min), McN-A-343 ($10^{-4}M$ for 2 min), cyclopiazonic acid ($10^{-5}$ for 4 min) and Bay-K-8644 ($10^{-5}$ M for 4 min). Also, under the presence of pinacidil ($10^{-4}$ M), which is also known to be a selective potassium channel activator, CA secretory responses evoked by ACh, high potassium, DMPP McN-A-343, Bay-K-8644 and cyclopiazonic acid were also greatly reduced. When preloaded along with quinine ($5{\times}10^{-5}M$) and glibenclamide ($10^{-6}$ M), a specific blocker of ATP-regulated potassium channels, CA secretory responses evoked by ACh, high potassium, DMPP McN-A-343, Bay-K-8644 and cyclopiazonic acid were recovered as compared to those of quinine-treatment only. taken together, these results demonstrate that quinine inhibits CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as by membrane depolarization through inhibiting influx of extracellular calcium and release in intracellular calcium in the rat adrenmodullary chromaffin cells. These findings suggest that activation of potassium channels may be involved at least in inhibitory action of quinine on CA secretion from the rat adrenal gland.

• Biomolecules & Therapeutics
• /
• 제8권1호
• /
• pp.13-21
• /
• 2000

The present study was designed to investigate the effect f quinidine on catecholamine (CA) secretion evoked by ACh, high $K^{+}$, DMPP, McN-A343, cyclopiazonic acid and Bay-K-8644 from the isolated perfused rat adrenal gland and to establish the mechanism of its action. The perfusion of quinidine (15-150 $\mu$M) into an adrenal vein for 60 min produced relatively dose- and time-dependent inhibition in CA secretion evoked by ACh (5.32$\times$10$^{-3}$ M), high $K^{+}$ (5.6$\times$10$^{-2}$ M), DMPP (10$^{-4}$ M for 2 min), McN-A-343 (10$^{-4}$ M for 2 min), cyclopiazonic acid (10$^{-5}$ M for 4 min) and Bay-K-8644 (10$^{-5}$ M for 4 min). Furthermore, in adrenal glands pre-loaded with quinine (5$\times$10$^{-5}$ M), CA secretory responses evoked by veratridine (10$^{-4}$ M) was time-dependently inhibited. Also, in the presence of lidocaine (10$^{-4}$ M), which is also known to be a sodium channel blocker, CA secretory responses evoked by ACh, high potassium, DMPP, McN-A-343, Bay-K-8644 and cyclo-piazonic acid were also greatly reduced in similar fashion to that of quinidine-treatment. Taken together, these results suggest that quinidine causes greatly the inhibition of CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors as well as by membrane depolarization, indicating strongly that this effect may be mediated by inhibiting influx of extracellular calcium and release in intracellular calcium in the rat adrenomedullary chromaffin cells. Furthermore, these findings indicate strongly that this inhibitory action of quinidine appears to be associated to the blocking action of sodium channels at least in CA secretion from the rat adrenal gland.and.

• The Korean Journal of Physiology and Pharmacology
• /
• 제9권1호
• /
• pp.29-35
• /
• 2005

To prove the buffering contribution of mitochondria to the increase of intracellular $Ca^{2+}$ level ($[Ca^{2+}]_i$) via background nonselective cation channel (background NSCC), we examined whether inhibition of mitochondria by protonophore carbonylcyanide m-chlorophenylhydrazone (CCCP) affects endothelial $Ca^{2+}$ entry and $Ca^{2+}$ buffering in freshly isolated rabbit aortic endothelial cells (RAECs). The ratio of fluorescence by fura-2 AM ($R_{340/380}$) was measured in RAECs. Biological state was checked by application of acetylcholine (ACh) and ACh ($10{\mu}M$) increased $R_{340/380}$ by $1.1{\pm}0.15$ ($mean{\pm}S.E.$, n=6). When the external $Na^+$ was totally replaced by $NMDG^+$, $R_{340/380}$ was increased by $1.19{\pm}0.17$ in a reversible manner (n=27). $NMDG^+$-induced $[Ca^{2+}]_i$ increase was followed by oscillatory decay after $[Ca^{2+}]_i$ reached the peak level. The increase of $[Ca^{2+}]_i$ by $NMDG^+$ was completely suppressed by replacement with $Cs^+$. When $1{\mu}M$ CCCP was applied to bath solution, the ratio of $[Ca^{2+}]_i$ was increased by $0.4{\pm}0.06$ (n=31). When $1{\mu}M$ CCCP was used for pretreatment before application of $NMDG^+$, oscillatory decay of $[Ca^{2+}]_i$ by $NMDG^+$ was significantly inhibited compared to the control (p＜0.05). In addition, $NMDG^+-induced$ increase of $[Ca^{2+}]_i$ was highly enhanced by pretreatment with $2{\mu}M$ CCCP by $320{\pm}93.7$%, compared to the control ($mean{\pm}S.E.$, n=12). From these results, it is concluded that mitochondria might have buffering contribution to the $[Ca^{2+}]_i$ increase through regulation of the background NSCC in RAECs.

• The Korean Journal of Physiology and Pharmacology
• /
• 제16권1호
• /
• pp.37-42
• /
• 2012

The aim of the present study was to elucidate the direct effects of melatonin on bladder activity and to determine the mechanisms responsible for the detrusor activity of melatonin in the isolated rat bladder. We evaluated the effects of melatonin on the contractions induced by phenylephrine (PE), acetylcholine (ACh), bethanechol (BCh), KCl, and electrical field stimulation (EFS) in 20 detrusor smooth muscle samples from Sprague-Dawley rats. To determine the mechanisms underlying the inhibitory responses to melatonin, melatonin-pretreated muscle strips were exposed to a calcium channel antagonist (verapamil), three potassium channel blockers [tetraethyl ammonium (TEA), 4-aminopyridine (4-AP), and glibenclamide], a direct voltage-dependent calcium channel opener (Bay K 8644), and a specific calcium/calmodulin-dependent kinase II (CaMKII) inhibitor (KN-93). Melatonin pretreatment ($10^{-8}{\sim}10^{-6}M$) decreased the contractile responses induced by PE ($10^{-9}{\sim}10^{-4}M$) and Ach ($10^{-9}{\sim}10^{-4}M$) in a dose-dependent manner. Melatonin ($10^{-7}M$) also blocked contraction induced by high KCl ($[KCl]_{ECF}$; 35 mM, 70 mM, 105 mM, and 140 mM) and EFS. Melatonin ($10^{-7}M$) potentiated the relaxation response of the strips by verapamil, but other potassium channel blockers did not change melatonin activity. Melatonin pretreatment significantly decreased contractile responses induced by Bay K 8644 ($10^{-11}{\sim}10^{-7}M$). KN-93 enhanced melatonin-induced relaxation. The present results suggest that melatonin can inhibit bladder smooth muscle contraction through a voltage-dependent, calcium-antagonistic mechanism and through the inhibition of the calmodulin/CaMKII system.

• 약학회지
• /
• 제44권1호
• /
• pp.80-86
• /
• 2000

TEA, glibenclamide, L-NAME and SKF 525A-induced contraction were investigated using acetylcholine, sodium nitroprusside (SNP, NO donor) and pinacidil (ATP sensitive $K^{+}$ channel opener) in rat abdominal and thoracic aorta. The relaxant effects of acetylcholine, SNP and pinacidil were not different in the abdominal aorta and in the thoracic aorta. Acetylcholine-induced relaxation was dependent on endothelial cell, but pinacidil was independent endothelia cell. In the presence of TEA, glibenclamide, L-NAME, mepacrine and SKF 525A, acetylcholine and SNP did not change, but pinacidil-induced relaxation was significantly reduced in presence of glibenclamide, which is ATP sensitive $K^{+}$ channel blocker. SKF 525A, which is inhibitor of cytochrome P$_{450}$ dependent epoxygenase, partially inhibited the pinacidil-induced relaxation. These results indicate that the pinacidil-induced relaxation may be mediated by ATP sensitive $K^{+}$ channel and partially by EETs, which is produced by cytochrome P$_{450}$ dependent epoxygenase.enase.

• Journal of Ginseng Research
• /
• 제34권4호
• /
• pp.314-320
• /
• 2010

The previous reports have showed that ginseng saponins, which are the active ingredients of Panax ginseng, cause the relaxation of artery that are contracted due to a various of hormones or potassium ($K^+$). Recently, we also showed that ginsenosides differentially regulate channel activity. The purpose of this study was to examine whether ginseng saponins affect contraction induced by $K^+$, serotonin (5-HT), or acetylcholine (Ach) in porcine coronary vessel. Treatment with concentrations of ginseng saponins caused a relaxation of 25 mM KCl-induced porcine coronary artery contraction. Also, ginseng saponin induced a significant dose-dependent relaxation of $3\;{\mu}M$ 5-HT-induced porcine coronary artery with the endothelium. In the porcine artery with the endothelium, ginseng saponins induced a relaxation by $3\;{\mu}M$ 5-HT in a concentration-dependent pattern. Ginseng saponins induced relaxation of both 25 mM KCl- and $3\;{\mu}M$ 5-HT-induced coronary artery contraction in the absence and presence of the endothelium. In contrast, treatment with $100\;{\mu}g/mL$ ginseng saponin did not induce relaxation in coronary artery contraction induced by Ach ($0.01\;{\mu}M$ to $30\;{\mu}M$) in the presence of the endothelium, but did cause significant relaxation of coronary artery contractions by Ach ($0.01\;{\mu}M$ to $30\;{\mu}M$) in the absence of the endothelium. These findings indicate that ginseng saponin (> $100\;{\mu}g/mL$) significantly inhibits porcine coronary artery contractions caused by $K^+$, 5-HT, and Ach. Therefore, in this study, we demonstrated that ginseng saponin may show beneficial roles on abnormal coronary contraction.

• The Korean Journal of Physiology and Pharmacology
• /
• 제15권1호
• /
• pp.17-22
• /
• 2011

Quercetin mainly exists in the skin of colored fruits and vegetables as one of flavonoids. Recent studies show that quercetin, like other flavonoids, has diverse pharmacological actions. However, relatively little is known about quercetin effects in the regulations of ligand-gated ion channels. In the previous reports, we have shown that quercetin regulates subsets of homomeric ligand-gated ion channels such as glycine, 5-$HT_{3A}$ and ${\alpha}7$ nicotinic acetylcholine receptors. In the present study, we examined quercetin effects on heteromeric neuronal ${\alpha}3{\beta}4$ nicotinic acetylcholine receptor channel activity expressed in Xenopus oocytes after injection of cRNA encoding bovine neuronal ${\alpha}3$ and ${\beta}4$ subunits. Treatment with acetylcholine elicited an inward peak current ($I_{ACh}$) in oocytes expressing ${\alpha}3{\beta}4$ nicotinic acetylcholine receptor. Co-treatment with quercetin and acetylcholine inhibited $I_{ACh}$ in oocytes expressing ${\alpha}3{\beta}4$ nicotinic acetylcholine receptors. The inhibition of $I_{ACh}$ by quercetin was reversible and concentration-dependent. The half-inhibitory concentration ($IC_{50}$) of quercetin was $14.9{\pm}0.8\;{\mu}M$ in oocytes expressing ${\alpha}3{\beta}4$ nicotinic acetylcholine receptor. The inhibition of $I_{ACh}$ by quercetin was voltage-independent and non-competitive. These results indicate that quercetin might regulate ${\alpha}3{\beta}4$ nicotinic acetylcholine receptor and this regulation might be one of the pharmacological actions of quercetin in nervous systems.

• 대한약리학회지
• /
• 제31권1호
• /
• pp.63-74
• /
• 1995

저산소 상태에서는 부신수질로부터 카테콜아민 (CA) 유리작용이 활성화되지만 반면에 소의 배양 chromaffin cell에서는 고통도의 $K^+$에 의한 CA 분비작용이 억제된다고 알려져 있다. 본 연구에서는 적출 흰쥐 관류부신에서 콜린성 자극과 막탈분극에 의한 CA 분비작용에 대한 저산소증의 영향을 검색하고 그 작용기전을 규명코자 하였다. 본 연구목적을 위하여, 적출 흰쥐 관류부신을 이용, 저산소증이 니코틴($N_1$), 무스카린($M_1$) 수용체 흥분약, 막탈분극 약물, 칼슘채널 활성화 약물, 세포내 칼슘유리 약물 및 ACh에 의한 CA 분비에 미치는 영향을 연구하였으며, 저산소증은 95% 질소 및 5% 이산화탄소 혼합가스를 Krebs액에 주입하여 유발시켰으며, $3{\sim}4$시간동안 유지하였다. 저산소증 유발시, DMPP ($100{\mu}M$), McN-A-343 ($100{\mu}M$), ACh (5.32 mM), Bay-K-8644 ($10{\mu}M$) 및 high $K^+$ (56 mM)에 의한 CA 분비작용을 시간의존적으로 점차 유의성인 감소를 나타내었다. 그러나, cyclopiazonic acid ($10{\mu}M$)에 의한 CA 분비반응에는 하등의 영향을 일으키지 못하였다. 또한 저산소증 자체가 CA의 기초분비 작용에는 영향을 미치지 않았다. 이와같은 실험결과로 보아, 저산소증시 콜린성 자극 및 막탈분극에 의한 CA 분비 작용이 억제되며, 이러한 억제작용은 chromaffin cell내로 $Ca^{++}$ 유입을 직접적으로 억제시키는 결과에 기인되며, 세포내 칼슘저장고로부터 칼슘유리작용과는 관계없는 것으로 사료된다.