• YAKHAK HOEJI
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• v.43 no.5
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• pp.665-673
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• 1999

This study was performed in order to investigate the effect of ketanserin, a specific antagonist of 5-HT2 receptor, on renal function in dogs. Ketanserin (50.0 and $150.0{\;}\mu\textrm{g}/kg$), when given intravenously, produced antidiuretic action accompanied with the decreased amounts of sodium and potassium excreted in urine (ENa, EK) and the increased reabsorption rates of sodium and potassium in renal tubules (RNa, RK). Ketanserin (50.0 and $50.0{\;}\mu\textrm{g}/kg$), when administered into a renal artery, elicited antidiuretic action in both experimental and control kidney, this time changes of renal function showed the same aspect as when given intravenously. Ketanserin (15.0 and $50.0{\;}\mu\textrm{g}/kg$) injected into the carotid artery exhibited also antidiuretic action and this antidiuretic action was not affected by renal denervation. Above results suggest that ketanserin elicits antidiuretic through central function, this central antidiuretic action is not mediated by renal nerves.

• Proceedings of the Korean Society of Applied Entomolohy Conference
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• 2003.10a
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• pp.98-98
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• 2003

• Korean Journal of Biological Psychiatry
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• v.6 no.2
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• pp.259-263
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• 1999

Nefazodone, a newer antidepressant is a phenylpiperazine derivative that inhibits the reuptake of both norepinephrine and serotonin, and antagonizes $5-HT_{2A}$ and ${\alpha}_1$ adrenergic receptors. Compared with SSRIs, nefazodone caused the fewer activating symptoms, adverse gastrointestinal effects(nausea, diarrhea, anorexia) and adverse effects of sexual function, but is associated with the more dizziness, dry mouth, constipation, visual disturbances and confusion. We report on 4 cases of visual disturbances and hallucinations in patients taking nefazodone. It is not certain what mechanisms mediated these side effects, but three mechanisms are possible. 1) Nefazodone, as a 5-HT2 antagonist, might induce visual disturbances. 2) mCPP, metabolite of nefazodone might contribute to the hallucination through action on 5-HT receptor. 3) Dopaminergic enhancing activity of nefazodone might cause hallucination. These case report raises the possibility that dose-related perceptual disturbances may exist with nefazodone. The fact emphasizes the need to pay close attention to all possible drug interactions, particularly in patients treated with multiple psychoactive agents, older patients, and patients with decreased hepatic function.

• The Korean Journal of Pharmacology
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• v.24 no.2
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• pp.203-216
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• 1988

To delineate the mechanisms of vasoconstriction and vasodilation in cerebral arteries the effects of some vasoconstrictors and calcium antagonists on the basilar artery (BA) and arterial circle of Willis (WC) were examined and also the role of endothelium in the action of these drugs was investigated in pigs, cats and rabbits. In pig cerebral arteries, dose-dependent contractile responses were elicited by KCI, histamine, 5-hydroxytryptamine (5-HT) and angiotensin, but norepinephrine (NE), phenylephrine (PE) and epinephrine (EP) elicited dose-dependent contractions only under pretreatment with propranolol 10-6 M. The magnitudes of maximal contractile effects of these drugs were different from each other, and 5-H~ was the largest and angiotensin the smallest. Some calcium antagonists dose-dependently inhibited KCI (35 mM)-induced contraction and the order of potency in inhibiting the contraction was nifedipine > > diltiazem > flunarizine > oxybutynin > isosorbide dinitrate (ISDN) > glyceryl trinitrate. 5-HT (10-6 M)-induced contraction was dosedependently inhibited by nifedipine but slightly inhibited by diltiazem and ISDN. In rings with intact endothelium, KCI (35 mM)-induced contraction was not affected by acetylcholine (ACh) but $PGF_{2{\alpha}}$ (lO-SM)-induced contraction was dose-dependently relaxed by ACh and adenosine. This endothelium-dependent relaxation was not affected by nifedipine (l0-6M)-pretreatment but markedly inhibited by methylene blue (50,uM)-pretreatment. In the porcine arterial rings without endothelium, ACh had no effect or even contracted the $PGF_{2{\alpha}}-induced$ contraction. However, the dosedependent relaxing effect of ACh appeared when the deendothelized porcine ring and rabbit thoracic aorta with intact endotheli urn were simultaneously suspended into a bath and this relaxing effect was also inhibited by methylene blue-pretreatment. In cat cerebral arteries, 5-HT and NE elicited dose-dependent contractile responses and ACh also produced dose-dependent contraction regardless of the existence of endothelium. ACh-induced contraction was most prominent. 5-HT (IO-SM)induced contraction was not relaxed but contracted additionally by ACh even in the intact endothelial ring. In rabbit cerebral arteries, 5-HT and NE elicited dose-dependent contractile responses and 5-HT-induced contraction was more prominent. In the intact endothelial preparations, 5-HT (lO-s M)-induced contraction was markedly relaxed by the addition of ACh( IO-SM) and this endothelium-dependent relaxing effect was inhibited by atropine (l0-7M)-pretreatment but notaffected by diltiazem (l0-6M)-pretreatment. These results suggest that ACh elicits endotheliumdependent relaxing effect mediated by muscarinic receptors in cerebral arteries of pig and rabbit, and that ACh acts as vasoconstrictor in cat cerebral artery.

• Proceedings of the Ginseng society Conference
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• 2006.05a
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• pp.77-77
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• 2006

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.23
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• pp.10045-10051
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• 2015

Chemotherapy is a major therapeutic approach for malignant neoplasms; however, due to the most common adverse events of nausea and vomiting, scheduled chemotherapeutic programs may be impeded or even interrupted, which severely impairs the efficacy. Aprepitants, 5-HT3 antagonists and dexamethasone are primary drugs used to prevent chemotherapy-induced nausea and vomiting (CINV). These drugs have excellent efficacy for control of acute vomiting but are relatively ineffective for delayed vomiting. Aprepitant may remedy this deficiency. Substance P was discovered in the 1930s and its association with vomiting was confirmed in the 1950s. This was followed by a period of non-peptide neurokinin-1 (NK-1) receptor antagonist synthesis and investigation in preclinical studies and clinical trials (phases I, II and III). The FDA granted permission for the clinical chemotherapeutic use of aprepitant in 2003. At present, the combined use of aprepitant, 5-HT3 antagonists and dexamethasone satisfactorily controls vomiting but not nausea. Therefore, new therapeutic approaches and drugs are still needed.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.6
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• pp.295-300
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• 2004

Serotonin (5-hydroxytroptamine, 5-HT) has been shown to affect the induction of long-term potentiation (LTP) in the cortex such as the hippocampus, the visual cortex and the prefrontal cortex. Fluoxetine, as a selective serotonin reuptake inhibitor, is used in the management of a wide variety of psychological diseases. To study the effect of fluoxetine on the induction of LTP, we recorded the field potential in layer II/III of the frontal cortex from 3-wk-old. LTP was induced in horizontal input by theta burst stimulation (TBS). TBS with two-folds intensity of the test stimulation induced LTP, which was blocked by application of D-AP5 $(50 {\mu}M)$, an NMDA receptor antagonist. Whereas bath application of 5-HT $(10 {\mu}M)$ inhibited the induction of LTP, treatment with the 5-HT depleting agent, para-chloroamphetamine $(PCA,\;10{\mu}M)$, for 2hr did not affect the induction of LTP. Bath application of fluoxetine (1, 3, and $10 {\mu}M)$ suppressed the induction of LTP in concentration-dependent manner, however, fluoxetine did not inhibit the induction of LTP in 5-HT-depleted slices. These results indicate that fluoxetine may inhibit the induction of LTP by modulating serotonergic mechanism in the rat frontal cortex.

• Proceedings of the Ginseng society Conference
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• 2005.11a
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• pp.32-40
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• 2005

The last two decades have shown a marked expansion in publications of diverse effects of Panax ginseng. Ginsenosides, as active ingredients of Panax ginseng, are saponins found in only ginseng. Recently, a line of evidences shows that ginsenosides regulate various types of ion channel activity such as Ca$^{2+}$, K$^+$, Na$^+$, Cl$^-$, or ligand gated ion channels (i.e. 5-HT$_3$, nicotinic acetylcholine, or NMDA receptor) in neuronal, non-neuronal cells, and heterologously expressed cells. Ginsenosides inhibit voltage-dependent Ca$^{2+}$, K$^+$, and Na$^+$ channels, whereas ginsenosides activate Ca$^{2+}$-activated Cl$^-$ and Ca$^{2+}$-activated K$^+$ channels. Ginsenosides also inhibit excitatory ligand-gated ion channels such as 5-HT$_3$. nicotinic acetylcholine, and NMDA receptors. This presentation will introduce recent findings on the ginsenoside-induced differential regulations of ion channel activities as a ligand as other drugs do.

• Bulletin of the Korean Chemical Society
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• v.31 no.8
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• pp.2371-2374
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• 2010

• The Korean Journal of Pharmacology
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• v.25 no.1
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• pp.1-11
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• 1989

In this study, it was aimed to investigate the role of serotonergic neurotransmission in nucleus tractus solitarius (NTS) for the central regulation of blood pressure and heart rate and its involvement in baroreceptor reflex activation in rats. A microinjection of 5-hydroxytryptamine (5-HT) into the NTS produced decreases in blood pressure and heart rate. Maximal decreases were $34.4{\pm}1.6$ mmHg and $41.7{\pm}10.2$ beats per min by 300 pmol of 5-HT. Microinjections of ${\alpha}-methylnor-adrenaline$ $({\alpha}-MNE)$ and clonidine manifested similar decreases in blood pressure and heart rate. The hypotensive and bradycardial effects of 5-HT were blocked by previous applications of 5-HT antagonists, ritanserin, methysergide and ketanserin into the NTS, respectively. By pretreatment with reserpine and 6-hydroxydopamine (6-OHDA, i.c.v.), both hypotensive and bradycardial effects of 5-HT were significantly attenuated. Pretreatment with 5, 7-dihydroxytryptamine (5,7-DHT, i.c.v.) enhanced the hypotensive and bradycardial effects of 5-HT. Similarly, following pretreatment with 6-OHDA, the effects of clonidine were increased. Pretreatment either with 5,7-DHT or 6-OHDA significantly attenuated the sensitivity of baroreflex produced either by phenylephrine or by sodium nitroprusside. When either 5,7-DHT or 6-OHDA was injected into the NTS $(5,7-DHT;\;8{\mu}g\;6-OHDA;\;10{\mu}g)$, both of the baroreflex sensitivities were impaired. In the immunohistochemical study, the injection of 6-OHDA into the the NTS led to reduction of axon terminal varicosity, however, the injection did not reduce the numbers of catecholaminergic cell bodies. Likewise, when 5,7-DHT was injected into the NTS, the varicosity of serotonergic axon terminals was markedly reduced. Based on these results, it is suggested that (1) stimulation of serotonergic receptors in the NTS leads to decreases in blood pressure and heart rate as observed with the stimulation of catecholaminergic system, (2) both serotonergic and catecholaminergic receptors may be located postsynaptically, and (3) the serotonergic neurons as well as catecholaminergic neurons may have a close relevance for the activation of baroreflex.