• Archives of Pharmacal Research
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• v.28 no.8
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• pp.914-922
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• 2005

The present study was designed to examine the effects of green tea extract (CUMC6335) and epigallocatechin gallate (EGCG) on secretion of catecholamines (CA) in the isolated perfused rabbit adrenal gland. In the presence of CUMC6335 $(200 {\mu}g/mL)$ into an adrenal vein for 60min, CA secretory responses evoked by ACh (5.32 mM), high $K^+$ (56 mM), DMPP $(100{\mu}M \;for\;2min)$, and Bay-K-8644 $(10{\mu}M\;for\;4min)$ from the isolated perfused rabbit adrenal glands were greatly inhibited in a time-dependent fashion. However, EGCG $(10{\mu}g/mL)$ did not affect CA release evoked by ACh, high $K^+$, and Bay-K-8644. CUMC6335 itself failed to affect basal catecholamine output. Taken together, these results demonstrate that CUMC6335 inhibits CA secretion evoked by stimulation of cholinergic nicotinic receptors, as well as the direct membrane depolarization from the isolated perfused rabbit adrenal gland. It is thought that this inhibitory effect of CUMC6335 may be due at least in part to the blocking action of the L-type dihydropyridine calcium channels in the rabbit adrenomedullary chromaffin cells, which is relevant to the cholinergic nicotinic blockade. It seems that there is a big difference in mode of action between CUMC6335 and EGCG.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.23 no.2
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• pp.93-98
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• 2012

Botulinum toxins are the most potent toxins known to mankind. Botulinum toxin acts by blocking the cholinergic neuromuscular or the cholinergic autonomic innervation of exocrine glands and smooth muscles. Seven distinct antigenic botulinum toxins (A, B, C, D, E, F and G) produced by different strains of Clostridium botulinum have been described and only A and B type of botulinum toxins were clinically used. Toxins were consisted of a heavy chain with a molecular weight of 100 kD and a light chain with a molecular weight of 50 kD. Toxins are bound with an astounding selectivity to glycoprotein structures located on the cholinergic nerve terminal. Subsequently light chain of toxin is internalized and cleaves different proteins of the acetylcholine transport protein cascade transporting the acetylcholine vesicle from the intracellular space into the synaptic cleft. After a decade of therapeutic application of the toxin, no anaphylaxis or deaths have been reported and systemic adverse effects have not been reported so far. However the toxin's immunologic properties can lead to the stimulation of antibody production, potentially rendering further treatments ineffective. Botulinum toxin is a safe and effective treatment. Use of botulinum toxin in clinical medicine has grown exponentially in recent years, and many parts of the human body are now being targeted for therapeutic purposes.

• Journal of Yeungnam Medical Science
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• v.8 no.2
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• pp.138-149
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• 1991

This study was aimed at investigation of the stimulatory innervations on the rat urinary bladder. Detrusor muscle strips of 15 mm long were suspended in isolated muscle chambers containing 1 ml of PSS maintained at $37^{\circ}C$ and aerated with 95% $O_2/5%CO_2$. Isometric myography was perfomed, and the results were as followings : Muscle strips showed "on-contraction" by electric field stimulation (EFS) frequency-dependently. The EFS-induced contraction was not affected by hexamethonium, a ganglion blocker, but abolished, by tetrodotoxin, a nerve conduction blocker. Physostigmine, a cholinesterase inhibitor enhanced the EFS-induced contraction which was inhibited by hemicholinium, an inhibitor of choline uptake at the cholinergic nerve ending. Such an EFS-induced contraction was antagonized by atropine only partially, and the atropine-resistant portion was completely abolished by the desensitization of purinergic receptors by prolonged incubatin of the strips in the presence of high concentratin of ATP. Bethanechol, a cholinergic agonist, elicited concentration-dependent contraction. Adenosine triphosphate (ATP), a purinergic agonist, induced a weak but concentration-dependent contraction of short duration. Bethanechol-induced contraction was not affected by ATP-desensitization, and ATP-induced contraction was not affected by tetrodotoxin. These results suggest that there are at least two main stimulatory components of innervations in the detrusor muscle, cholinergic muscarinic and purinergic ; and those receptors are independent each other.

• Biomolecules & Therapeutics
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• v.19 no.3
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• pp.315-319
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• 2011

Galanin (Gal) is a 29-amino-acid neuropeptide which is expressed in superior cervical ganglion (SCG) neurons and plays a trophic role in the adult animal and acts as an inhibitory modulator of cholinergic and noradrenergic neurotransmission. Whether activation or inhibition of alpha-adrenoreceptors infl uences Gal mRNA expression in SCG neurons remains unknown. Here, we have evaluated the possible regulation of Gal mRNA expression with acute (4 h) and chronic (4 days) stimulation of alpha 1- and alpha 2-adrenoreceptor agonists or antagonists in primary cultured SCG neurons. The results showed that the amount of Gal mRNA expression in cultured SCG neurons increased signifi cantly after chronic stimulation with alpha 2-adrenoreceptor antagonist yohimbine compared with control SCG neurons at the same time point, whereas the amount of Gal mRNA expression decreased signifi cantly after chronic stimulation with alpha 2-adrenoreceptor agonist clonidine as compared with that in control group. All these effects were not dose-dependent on the administration of alpha 2-adrenoreceptor agonist clonidine or alpha 2-adrenoreceptor antagonist yohimbine. Alpha 1-adrenoreceptor agonist phenylephrine or antagonist prazosin chronic stimulation did not have effects on Gal mRNA expression. Acute exposure of these agents did not have effects on Gal mRNA expression. The present study showed that Gal may be regulated by activation or inhibition of alpha 2-adrenoreceptors, but not alpha 1-adrenoreceptors in sympathetic neurons.

• Korean Journal of Veterinary Research
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• v.14 no.1
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• pp.33-40
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• 1974

It has been generally understood that the intestinal tracts are under the control of the autonomic nerves; the parasympathetics are excitatory and the sympathetics inhibitory. However, it is recently reported that the actions of these autonomic nerves in the newborn animals are shown to be different from those in the adult animals in some species. In order to elucidate the role of sympathetic innervation to the intestinal tracts, the effects of periarterial nerve stimulation were studied in the periarterial sympathetics-jejunum preparations of the chick and the effects of some autonomic drugs on the isolated muscle strips were also studied. The results obtained were as follows: 1. The periarterial stimulation in the periarterial sympathetics-jejunum preparation elicited the responses of three patterns; 1) contrcation followed by relaxation 2) contraction only 3) relaxation only. The excitatory response was most effective in the stimulus frequencies of 40 cps, whereas the inhibitory response was maximal in the stimulus frequencies of 30 cycle per second. 2. The excitatory response to the periarterial stimulation was not affected by the pretreatment with phenoxybenzamine, dibenamine, propranolol and atropine, whereas the inhibitory response was completely blocked by the pretreatment with phenoxybenzamine and propranolol. 3. In the periarterial syrnpathetics-jejunum preparation treated with reserpine, the periarterial stimulation evoked only contraction, and the contraction was not affected by the pretreatment with phenoxybenzamine, propranolol and atropine. 4. The administration of norepinephrine evoked a relaxation in the isolated jejunum muscle strips and the effect was completely blocked by the pretreatment with phenoxybenzamine. 5. The administration of isoproterenol produced a relaxation in the isolated jejunum muscle strips and the effect was not affected by pretreatment with phenoxybenzamine, whereas the effect was completely blocked by the pretratment with propranolol. 6) The administration of acetylcholine produced a marked contraction in the isolated jejunum muscle strips and the effect was completely abolished by the pretreatment of atropine. These experimental evidences indicate that the inhibitory response to the periarterial stimulation is due to adrenergic fibers and the excitatory response is due to neither adrenergic nor cholinergic component.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.2
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• pp.109-112
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• 2002

The signal pathways involved in the regulation of AP-1 DNA binding activity in long-term nicotine stimulated bovine adrenal medullary chromaffin (BAMC) cells have not been well characterized. To understand the involvement of second messengers in the regulation of AP-1 DNA binding activity, the present study was designed to define the time-course for inhibition of nicotine-induced responses by cholinergic antagonists, $Ca^{2+}$ and calmodulin (CaM) antagonists, and calcium/calmodulin-dependent protein kinase (CaMK) II inhibitor using electrophoretic mobility shift assay. Nicotine $(10{\mu}M)$ stimulation increased AP-1 DNA binding activity at 24 hr after treatment. Posttreatment with hexamethonium (1 mM) plus atropine $(1{\mu}M)$ (HA), nimodipine $(1{\mu}M),$ or calmidazolium $(1{\mu}M)$ at 0.5, 3, and 6 hr after the nicotine treatment significantly inhibited the AP-1 DNA binding activity increased by long-term nicotine stimulation. However, posttreatment with HA, nimodipine, or calmidazolium at 9 or 12 hr after the nicotine treatment did not affect the nicotine-induced increase of AP-1 DNA binding activity. The pretreatment of BAMC cells with various concentrations of KN-62 inhibited the increase of AP-1 DNA binding activity induced by nicotine in a concentration-dependent manner. KN-62 $(10{\mu}M)$ posttreatment beginning at 0.5, 3, or 6 hr after the nicotine treatment significantly inhibited the increase of AP-1 DNA binding activity. However, KN-62 posttreatment beginning at 9 or 12 hr after the nicotine treatment did not affect the increase of AP-1 DNA binding activity. This study suggested that stimulation (for at least 6 hr) of nicotinic receptors on BAMC cells was necessary for increase of AP-1 DNA binding activity, and activation of $Ca^{2+},$ CaM, and CaMK II up to 6 hr at least seemed to be required for the increase of nicotine-induced AP-1 DNA binding activity.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.5
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• pp.311-316
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• 2010

It is well-known that electrical field stimulation (EFS)-induced contraction is mediated by a cholinergic mechanism and other neurotransmitters. NO, ATP, calcitonin gene-related peptide (CGRP), and substance P are released by EFS. To investigate the purinergic mechanism involved in the EFS-induced contraction, purinegic receptors antagonists were used. Suramine, a non-selective P2 receptor antagonist, reduced the contraction induced by EFS. NF023 ($10^{-7}{\sim}10^{-4}M$), a selective P2X antagonist, inhibited the contraction evoked by EFS. Reactive blue ($10^{-6}{\sim}10^{-4}M$), selective P2Y antagonist, also blocked the contraction in a dose-dependent manner. In addition, P2X agonist ${\alpha}$,${\beta}$-methylene 5'-adenosine triphosphate (${\alpha}{\beta}MeATP$, $10^{-7}{\sim}10^{-5}M$) potentiated EFS-induced contraction in a dose-dependent manner. P2Y agonist adenosine 5'-[${\beta}$-thio]diphosphate trilithium salt ($ADP{\beta}S$, $10^{-7}{\sim}10^{-5}M$) also potentiated EFS-induced contractions in a dose-dependent manner. Ecto-ATPase activator apyrase (5 and 10 U/ml) reduced EFS-induced contractions. Inversely, 6-N,$N$-diethyl-D-${\beta}$,${\gamma}$- dibromomethylene 5'-triphosphate triammonium (ARL 67156, $10^{-4}M$) increased EFS-induced contraction. These data suggest that endogenous ATP plays a role in EFS-induced contractions which are mediated through both P2X-receptors and P2Y-receptors stimulation in cat esophageal smooth muscle.

• The Korean Journal of Physiology and Pharmacology
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• v.14 no.1
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• pp.29-35
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• 2010

We have shown that myosin light chain kinase (MLCK) was required for the off-contraction in response to the electrical field stimulation (EFS) of feline esophageal smooth muscle. In this study, we investigated whether protein kinase C (PKC) may require the on-contraction in response to EFS using feline esophageal smooth muscle. The contractions were recorded using an isometric force transducer. On-contraction occurred in the presence of $N^G$-nitro-L-arginine methyl ester (L-NAME), suggesting that nitric oxide acts as an inhibitory mediator in smooth muscle. The excitatory composition of both contractions was cholinergic dependent which was blocked by tetrodotoxin or atropine. The on-contraction was abolished in $Ca^{2+}$-free buffer but reappeared in normal $Ca^{2+}$-containing buffer indicating that the contraction was $Ca^{2+}$ dependent. 4-aminopyridine (4-AP), voltage-dependent $K^+$ channel blocker, significantly enhanced on-contraction. Aluminum fluoride (a G-protein activator) increased on-contraction. Pertussis toxin (a $G_i$ inactivator) and C3 exoenzyme (a rhoA inactivator) significantly decreased on-contraction suggesting that Gi or rhoA protein may be related with $Ca^{2+}$ and $K^+$ channel. ML-9, a MLCK inhibitor, significantly inhibited on-contraction, and chelerythrine (PKC inhibitor) affected on the contraction. These results suggest that endogenous cholinergic contractions activated directly by low-frequency EFS may be mediated by $Ca^{2+}$, and G proteins, such as Gi and rhoA, which resulted in the activation of MLCK, and PKC to produce the contraction in feline distal esophageal smooth muscle.

• The Korean Journal of Pharmacology
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• v.27 no.2
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• pp.167-181
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• 1991

The present study was an attempt to investigate the effect of forskolin on secretion of catecholamines (CA) evoked by Ach, excess $K^+$, DMPP, McN-A-343 and caffeine from the isolated perfused rat adrenal glands and to elucidate its mechanism of action. The perfusion with forskolin (1.0 uM) for 1 min into the adrenal vein enhanced markedly the secreation of CA evoked by Ach (50 ug), excess $K^+$ (56 mM) DMPP (100 uM) and by caffeine (0.3 mM) but did not that by McN-A-343. Forskolin alone did not potentiate the CA secretion. Moreover, forskolin augmented the CA release evoked by the above same stimulation even in the absence of extracellular calcium. The 1 min perfusion of 300 uM-dibutyryl cyclic AMP (DBcAMP), which is known to increase cyclic AMP levels, led to enhancement of Ca secretion evoked by Ach, excess $K^+$ and DMPP but did not that by McN-A-343 and caffeine. DBcAMP by itself also did not augment the CA secretion. In the calcium-free medium DBcAMP significantly enhanced the CA secretion by the same stimulation, except for the case of McN-A-343. These experimental results suggest that forskolin activates adenylate cyclase, resulting the elevation of cyclic AMP which may potentiate cholinergic nicotinic receptor-mediated and also depolarization-dependent CA secretion and that it may alter the intracellular calcium homeostasis in the rat adrenal glands.

• The Korean Journal of Physiology
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• v.21 no.2
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• pp.225-239
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• 1987

The effects of adenosine on the mechanical contractions and electrical activities were investigated in guinea-pig stomach. Spontaneous contractions of the antral region were recorded with force transducer, and the phasic contractions of fundic region were induced by electrical field stimulation. Electrical responses of smocth muscle cells were recored using glass capillary microelectrodes filled with 3M-KCl. Field stimulation was applied transmurally by using a pair of platinum wire (0.5 mm in diameter) placed on both sides of tissue. All experiments were performed in tris-buffered Tyrode solution which was aerated with 100% $O_2$ and kept at $35^{\circ}C$. The results obtained were as follows. 1) Adenosine suppressed the spontaneous contractions of antrum in a dose-dependent manner. 2) The inhibitory effect on antral spontaneous contractions was not influenced by the administration of guanethidine $(5{\times}10^{-6}\;M)$ and atropine $10^{-6}\;M$, or in the presence of dipyridamole $10^{-7}\;M$. 3) The phasic contractions of fundus induced by electrical field stimulation, which disappeared rapidly by the addition of tetrodotoxin $(3{\times}10^{-7}\;M)$, were potentiated by adenosine in the presence of guanethidine. 4) Adenosine decreased the amplitude and the maximum rate of rise of slow waves, and the increased amplitude and rate of rise evoked in the high calcium solution or in the presence of TEA were decreased by adenosine. 5) The non-adrenergic, non-cholinergic inhibitory junction potential (IJP) was inhibited by adenosine in the antral region, while the excitatory junction potential (EJP) in the fundic region was potentiated. From the above results, the following conclusions could be made. 1) Adenosine suppresses the spontaneous contractions of antrum strip by the decrease in amplitude and rate of rise of slow waves. 2) The release of neurotransmitter(s) from non-adrenergic, non-cholinergic nerve terminals is inhibited by adenosine.