• The Korean Journal of Physiology and Pharmacology
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• 제6권2호
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• pp.63-70
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• 2002

Cholinergic modulation of GABAergic spontaneous miniature inhibitory postsynaptic currents (mIPSCs) by the activation of muscarine receptors was investigated in mechanically dissociated rat nucleus basalis of the Meynert neurons using the conventional whole-cell patch recording configuration. Muscarine $(10{\mu}M)$ reversibly and concentration-dependently decreased mIPSC frequency without affecting the current amplitude distribution. Muscarine action on GABAergic mIPSCs was completely blocked by $1{\mu}M$ methoctramine, a selective $M_2$ receptor antagonist, but not by $1{\mu}M$ pirenzepine, a selective $M_1$ receptor antagonist. NEM $(10{\mu}M),$ a G-protein uncoupler, attenuated the inhibitory action of muscarine on GABAergic mIPSC frequency. Muscarine still could decrease GABAergic mIPSC frequency even in the $Ca^{2+}-free$ external solution. However, the inhibitory action of muscarine on GABAergic mIPSCs was completely occluded in the presence of forskolin. The results suggest that muscarine acts presynaptically and reduces the probability of spontaneous GABA release, and that such muscarine-induced inhibitory action seems to be mediated by G-protein-coupled $M_2$ receptors, via the reduction of cAMP production. Accordingly, $M_2$ receptor-mediated disinhibition of nBM neurons might play one of important roles in the regulation of cholinergic outputs from nBM neurons as well as the excitability of nBM neurons themselves.

• 대한약리학회지
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• 제27권1호
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• pp.21-31
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• 1991

미주신경절단 가토에서 니코틴성약물인 nicotine과 DMPP뿐아니라 무스카린성 약물인 muscarine과 bethanechol은 측뇌실내 투여로 모두 혈압상승작용을 나타냈다. Nicotine과 DMPP에 대한 승압반응은 측뇌실내 mecamylamine처리로 현저히 감약되었으나 측뇌실내 pirenzepine처리에 의해서는 영향받지 않았고, muscarine과 bethanechol에 대한 승압반응은 pirenzepin에 의해서는 억제되나 mecamylamine에 의해서는 영향받지 않았다. 이는 뇌내의 니코틴성 수용체 및 무스카린성 수용체가 모두 혈압상승에 관여함을 가리키고 있다. Nicotine과 muscarine에 대한 승압반응은 regitine, reserpine, enalapril, saralasin, SK&F-100273, regitine과 enalapril, regitine과 saralasin의 정맥내 처리에 의해서는 억제되지 않았으며 nicotine에 대한 승압반응은 regitine과 SK&F-100273 두약물의 병용처리에 의해서 억제되었고 muscarine에 의한 승압반응은 regitine, enalapril과 SK&F-100273의 세가지 약물의 병용처리에 의해서만 억제되었다. Nicotine이나 muscarine에 의한 혈압상승상태에서 정맥내 regitine의 투여는 혈압하강을 일으켰으나 enalapril이나 SK&F-100273은 혈압하강을 일으키지 못하였다. Enalapril은 regitine처리나 regitine과 SK&F-100273병용처리 가토에서 nicotine에 의해 상승된 혈압을 하강시키지 못하였으나 SK&F-100273은 regitine처리 가토에서 nicotine에 의한 상승된 혈압을 하강시켰다. Enalapril은 이러한 SK&F-100273의 할압하강작용을 강화시키지 못하였다. Enalapril은 regitine 처리 가토에서 muscarine에 의하여 상승된 혈압은 하강시키지 못하였으나, regitine과 SK&F-100273병용처리 가토에서 muscarine에 의해 상승된 혈압은 하강시켰다. SK&F-100273은 regitine처리 가토에서 muscarine에 의해 상승된 혈압을 하강시키지 못했으나 regitine과 enalapril병용처리 가토의 상승된 혈압은 하강시켰다. 이상의 성적은 뇌실내 nicotine에 의한 혈압상승에는 말초에서 교감신경계와 vasopressin이 관여하며 muscarine에 의한 혈압상승에는 교감신경계, vasopressin 및 angiotensin계가 관여함을 시사하고 있다. Regitine의 정상 가토 혈압하강작용은 enalapril이나 SK&F-100273의 단독처리에 의해서는 영향받지 않았으나 이 두약물을 병용처리시에는 유의하게 강화되었고, 이는 가토 동맥압의 유지에 교감신경, renin-angiotensin 및 vasopressin계가 관여함을 시사하고 있다.

• Toxicological Research
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• 제2권2호
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• pp.51-62
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• 1986

Of mushrooms found in Japan, approximately 35 species are classified as poisonous mushrooms. The mushroom poisonings caused by these mushrooms are classified as three types accodring to the symptoms and their toxic constitutents. The first type is the cholera-like symptom which is induced mainly by the toxic constitutents such as cyclopeptide and gyromitrin. The second type is the neurological mainfestations induced by muscarine (cholinergic), muscimol (delirium), psilocybin (hallucinogenic) and coprine (antabuse-like).

• 한국균학회지
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• 제49권2호
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• pp.139-153
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• 2021

The Inocybaceae is a family of ectomycorrhizal fungi belonging to the Agaricales order. Most species in this family produce secondary metabolites, such as muscarine, psilocybin, and other compounds. In the present study, we conducted taxonomic studies on the Inocybaceae based on morphological and molecular phylogenetic analyses for the first time in Korea. As a result, seven species of Inocybaceae were newly recorded: Inocybe caroticolor, I. fuscidula, I. grammatoides, I. latibulosa, I. stellata, Inosperma shawarense, and Mallocybe malenconii. Among them, the genera Inosperma and Mallocybe were described for the first time in Korea. Relevant morphological characteristics, phylogenetic trees, and photographs are provided.

• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1998년도 Advances in Ginseng Research - Proceedings of the 7th International Symposium on Ginseng -
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• pp.40-46
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• 1998

We investigated the influence of the root of Panax ginseng C. A. Meyer on the secretion of catecholamines from bovine adrenal chromaffin cells, which are used as a model of nervous systems. In two major parts extracted from the ginseng root, the crude saponin fraction, but not the non-saponin fraction, reduced the secretion from the cells, stimulated by acetylcholine (ACh). Ginseng saponins (ginsenosides) are classified into three groups, the panaxadiol, the panaxatriol and the oleanolic acid groups, on the basis of the chemical structures of their saponins. Both the panaxadiol and the panaxatriol saponins, excluding only one oleanolic acid saponin ginsenoside-Ro, generally reduced the ACh-evoked secretion. The inhibitory effects of the panaxatriol were much stronger than those of the panaxadiol. However, ginsenoside-Rg, and -Rh3 in the panaxadiol saponins were the potent inhibitors comparable to the panaxatriol saponins. Ginsenoside-Rg2 in the panaxatriol was the most effective. It is probable that the ginsenoside inhibition of the catecholamine secretion is due to the suppression of the function of the nicotinic ACh receptor-cation channels. On the other hand, ginsenoside-Rg2 did not affect the angiotensin II-, the bradykinin-, the histamine- and the neurotensin- induced catecholamine secretions from the chromaffin cells and the muscarine- and the histamine- induced contraction of the ileum in guinea-pigs. Ginsenoside-Rbl, a panaxadiol saponin, and ginsenoside-Ro had no or only a slight effect on them. On the contrary, ginsenoside-Rg3 not only competitively inhibited the muscarine-induced ileum contraction but also reduced the angiotensin R -, the bradykinin-, the histamine- and the neurotensin-induced catecholamine secretions. Thus, the ginseng root contains active ingredients, namely some ginsensides, which suppress the responses induced by receptor stimulation. The inhibitory effects of ginseng saponins may be one of the action mechanisms for the pharmacological effects of the Panax ginseng root.

• The Korean Journal of Physiology
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• 제26권2호
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• pp.137-141
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• 1992

The present study was aimed at elucidating the mode of inhibitory action of tricyclic antidepressants on the smooth muscle. Effects of amitriptyline on the isolated detrusor muscle strips of the urinary bladder of the rabbit were examined. The spontaneous rhythmic movement of the muscle preparation was frequently observed, which was decreased or abolished by addition of amitriptyline $(10^{-5}{\sim}10^{-3}\;M)$. The muscle preparation responded with contraction dose dependently to carbachol, of which dose response curve shifted to the right in the presence of either amitriptyline or atropine. However, amitriptyline produced a nonparallel shift, whereas atropine caused a parallel one. In calcium free medium, the contraction response to carbachol was markedly decreased, which was resumed by the addition of $CaCl_2$ (2.5mM), but not in the presence of either amitriptyline or nifedipine. KCI (60 mM) produced a potent contraction, which was abolished in the presence of amitriptyline or nifedipine. These results suggest that amitriptyline, unlike atropine, not only acts as a noncompetitive antagonist at cholinergic muscarine receptors but also inhibits Ca-influx through the muscle cell membrane.

• Biomolecules & Therapeutics
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• 제3권3호
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• pp.192-198
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• 1995

The affinity of mequitazine, a non-sedating antihistamine, for muscarinic receptors was evaluated in the guinea-pig ventricle and ileum by in vitro binding techniques and functional studies. In binding studies, [$^3$H]quinuclidinyl benzilate (QNB) identified a single class of muscarinic receptors with similar apparent $K_{D}$ value of about 100 pM in two tissues. Mequitazine inhibited [$^3$H]QNB binding to muscarinic receptors competitively. Analysis of the mequitazine inhibition curve of [$^3$H]QNB binding to ventricular microsome and ileal homogenate indicated the presence of a single homogeneous binding site with Ki value of 25 nM and 18 nM, respectively. In functional studies, mequitazine caused parallel rightward shifts of concentration-response curves for carbachol and histamine in the isolated guinea-pig ileum. The slope values obtained from Schild plot analysis for the antagonistic action of mequitazine on muscarinic and histamine $H_1$-receptors were not significantly different from unity. The p $A_2$values of mequitazine for muscarinic and histamine $H_1$-receptors were about 7.6 ( $K_{M}$= 25.1 nM) and 8.88 ( $K_{H}$= 1.32 nM), respectively. These results indicate that the muscarinic receptor blocking action of mequitazine is 15 times less potent than the $H_1$receptor blocking action, but high concentration of this drug may cause the peripheral muscarinic receptor blocking effect.t.t.t.

• Biomolecules & Therapeutics
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• 제2권4호
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• pp.361-368
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• 1994

The nature of the muscarinic receptors in bovine adrenal medulla was investigated in this study. [$^3$H]Quinuclidinyl benzilate(QNB) specifically bound to a single class of muscarinic receptor with a $K_{D}$ value of about 70 pM in bovine adrenal medullary, cardiac ventricular and ileal homogenates. Pirenzepine inhibition curves of [$^3$H]QNB binding to cardiac ventricular and ileal homogenates were steep, indicating the presence of a single class of binding site for pirenzepine with a Ki value of 990 nM and 508 nM, respectively. However, pirenzepine/[$^3$H]QNB competition binding curves in adrenal medulla suggested the presence of two binding sites (Hill coefficient=0.59) with a high( $M_1$) and a low( $M_2$) affinity. Respective Ki values for pirenfepine were 16 nM and 633 nM, with 44% of total sites having a high affinity( $M_1$). Gallamine, which is selective to cardiac $M_2$-receptor, inhibited [$^3$H]QNB binding to adrenal medullary, cardiac ventricular and ileal homogenates with Ki values of 12 $\mu$M, 6 $\mu$M and 13 $\mu$M, respectively. Thus, the binding affinities of pirenzepine and gallamine for $M_2$-receptor in adrenal medulla were similar to those in ileum, which contains the $M_3$-receptor. These results indicate that the $M_1$- and $M_3$- muscarinic receptor subtypes coexist in the bovine adrenal medulla.a.

• The Korean Journal of Physiology and Pharmacology
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• 제9권1호
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• pp.37-43
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• 2005

Our previous report demonstrated that chick myoblasts are equipped with $Ca^{2+}$-permeable stretchactivated channels and $Ca^{2+}-activated$ potassium channels ($K_{Ca}$), and that hyperpolarization-induced by $K_{Ca}$ channels provides driving force for $Ca^{2+}$ influx through the stretch-activated channels into the cells. Here, we showed that acetylcholine (ACh) also hyperpolarized the membrane of cultured chick myoblasts, suggesting that nicotinic acetylcholine receptor (nAChR) may be another pathway for $Ca^{2+}$ influx. Under cell-attatched patch configuration, ACh increased the open probability of $K_{Ca}$ channels from 0.007 to 0.055 only when extracellular $Ca^{2+}$ was present. Nicotine, a nAChR agonist, increased the open probability of $K_{Ca}$ channels from 0.008 to 0.023, whereas muscarine failed to do so. Since the activity of $K_{Ca}$ channel is sensitive to intracellular $Ca^{2+}$ level, nAChR seems to be capable of inducing $Ca^{2+}$ influx. Using the $Ca^{2+}$ imaging analysis, we were able to provide direct evidence that ACh induced $Ca^{2+}$ influx from extracellular solution, which was dramatically increased by valinomycin-mediated hyperpolarization. In addition, ACh hyperpolarized the membrane potential from $-12.5{\pm}3$ to $-31.2{\pm}5$ mV by generating the outward current through $K_{Ca}$ channels. These results suggest that activation of nAChR increases $Ca^{2+}$ influx, which activates $K_{Ca}$ channels, thereby hyperpolarizing the membrane potential in chick myoblasts.

• 한국한의학연구원논문집
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• 제2권1호
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• pp.236-254
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• 1996

This study was carried out to investigate the tracheal muscle relaxation of water extracts of three kinds of Coptis rhizoma and also compare their effects with berberine and palmatine, which are the important alkaloid components of Coptis rhizoma, in isolated rat tracheal smooth muscle. As a result Coptis chinenis showed significant tracheal muscle relaxation on KCI-induced contraction and more markedly on carbachol-induced contraction in dose-dependent manner. Coptis japoinin exhibited also tracheal muscle relaxation on both contraction with slightly weaker activities than those of Coptis chinensts. The activities of the root hair of Coptis chinensis were the most weakest in three rhizomas. Berberine and palmatine had strong tracheal muscle relaxation, especially, on carbachol-induced contraction, however, their activities on KCI-induced contraction were weaker than that of Coptis chinenis. The inhibitory effects of three kinds of Coptis rhizoma on the contraction by KCI and carbachol were investigated to explain the process of their tracheal muscle relaxation. All rhizomas inhibited the contraction by both agents, among them, Coptis japonica showed the most significant effect, so indicating that the tracheal muscle relaxation of Coptis rhizoma may be concerned with the blocking of muscarine receptor and $Ca^{2+}$channel.