• Journal of Veterinary Clinics
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• v.29 no.1
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• pp.107-111
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• 2012

Three dogs (An 8 years-old intact female Poodle, a 7 years-old intact male Schunauzer, and an 8 yearsold Golden Retriever) were presented due to acute vomiting, dyspnea, and generalized weakness. Megaesophagus was confirmed through radiographic examination in all 3 dogs. Relative oesophageal diameter (ROD) was measured and results of ROD measurements showed the possibility of megaesophagus secondary to myasthenia gravis in three dogs. Thus we performed anticholinesterase test as screening test for myasthenia gravis. In all three dogs, esophageal diameter was reduced after neostigmine methylsulfate administration. For definite diagnosis of acquired myasthenia gravis, serum acetylcholine receptor antibody titer was measured, but definite diagnosis was confirmed only in one case. However, based on history, radiographic findings, anticholinesterase test, ROD measurement, other two cases were still suspected as megaesophagus secondary to myasthenia gravis. Treatment with pyridostigmine bromide was initiated in all dogs, and improvement of esophageal diameter was shown in all dogs. One dog was successfully managed for 15 months after initial treatment and, is still alive, but other two dogs were died shortly after initial treatment, because of severe aspiration pneumonia.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1995.04a
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• pp.90-90
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• 1995

The Influence of age on the endothelial modulation of angiotensin II (AII)-induced contractile response was investigated in isolated aortic rings of rats ranging in age from 0.7 to 20 months. Hemoglobin and L-NAME were used to examine whether age-related changes in the EDRF-releasing system were involved in endothelial modulation of All-induced contraction in rat aorta. In all five age groups (0.7, 1.5, 3, 6, 20 months), hemoglobin (10 ${\mu}$M) significantly enhanced All-induced contractile response only in aorta with endothelium intact. L-NAME (10 ${\mu}$M) Produced a significant enhancement in All responses in endothelium-intact aortas from rats aged 0.7 and 1.5 months, but it had no effect in aortas from older rats aged 6 and 20 months. Indomethacin (10 ${\mu}$M) did not affect All-induced contractile responses in both endothelium intact and removed aortas from rats at the age of 0.7 to 20 months. Hemoglobin (10 ${\mu}$M) abolished acetylcholine-induced relaxation response in aortas from young and old rats. L-NAME completely abolished the relaxation in aortas from young (0.7 and 1.5 months), but incompletely in aortas from older (6 and 20 months) rats. The sensitivity of endothelium-dependent relaxation to A23187 increased with age between ages of 0.7 and 6 months, with no further increase noted up to 20 months of age. These results suggest that endothelial modulation of AII-induced contraction in rat aorta might involve age-related alteration in EDRF-releasing system, probably via post-receptor mechanism.

• The Korean Journal of Pharmacology
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• v.16 no.1 s.26
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• pp.57-63
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• 1980

The Pharmacologic action of ethanol extracts and essential substance obtained from fruits of Evodia rutaecarpa are studied. 1) Motility of the isolated rabbit-intestine was decreased in proportion to the concentration of essential substance. 2) Intestinal contraction induced by acetylcholine 10? 6g/ml was inhibited by the essential substance $10^{-5}g/ml$. 3) Contractile responses of the isolated rabbit-intestine by serotonin $10^{-5}g/ml$ and histamine $10^{-5}g/ml$ were depressed significantly with the essential substance $10^{-5}g/ml$. 4) Alpha adrenergic receptor blocking effect of dihydroergotamine was interfered significantly with the essential substance. 5) Analgesic effect in mice by acetic acid stimulating method was observed significantly with both of the ethanol extracts and essential substance. 6) Blood pressure and respiration of the rabbits were not significantly influenced with the essential substance.

• Biomolecules & Therapeutics
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• v.7 no.4
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• pp.307-314
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• 1999

The human muscarinic acetylcholine receptor (mAChR) subtypes Hml, Hm2 and Hm3 have been expressed in insect cells (Spodoptera frugiperda, Sf9) using the baculovirus expression system. Expression of relevant DNA, transcript and receptor proteins was identified by PCR, Northern blotting and [$^{3}H$]QNB binding, respectively. As assessed by [$^{3}H$]QNB binding sites, yields of muscarinic receptors in membrane preparations in this study were as about 5-20 times high as those in mammalian cells reported in previous studies. The [$^{3}H$]QNB competition binding studies with well-known subtype-selective mAChR antagonists showed that the receptors expressed in Sf9 cells retain the pharmacological characteristics expected for the ml , m2 and m3 muscarinic receptors. The ml-selective antagonist, pirenzepine, displayed a considerably higher affinity for Hml by 110-fold and 35-fold than for Hm2 and Hm3, respectively, The m2-selective methoctramine displayed a significantly higher affinity for Hm2 than for Hml and Hm3 (10- and 26-fold, respectively). p-F-HHSiD exhibited high affinity for Hm3 that is not significantly different from those for Hml, but 66-fold higher than its affinity for Hm2. The functional coupling of the recombinant receptors to second messenger systems was also examined. While both Hml and Hm3 stimulated phosphoinositide hydrolysis upon activation by carba-chol, Hm2 produced no response. On the other hand, activation of mAChRs induced the inhibition of forsko-lin-stimulated cyclic AMP formation in Hm2-expressing cells, whereas the significant dose-dependent increase in or poor response on cyclic AMP formation were produced in Hml or Hm3-expressing cells, respectively. These results indicate the differential coupling of recombinant Hml, Hm2 and Hm3 receptors expressed in SF9 cells to intracellular signalling system.

• Korean Journal of Veterinary Research
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• v.34 no.3
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• pp.447-456
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• 1994

In order to elucidate the characterization of receptors involved in inestinal motility of Israeli carp, spontaneously contracting Israeli carp intestinal preperations were prepared and mounted in the organ chambers for contraction traicings using a polygraph. Various contractile agonists were treated and their dose-response curves were constructed. $EC_{50}$ values$(pD_2)$ of each agonist on specific receptors, $pA_2$ values of competitive antagonists against some agonists, and $K_1$, values of noncompetitive antagonists against some agonists were analyzed for characterization of receptors related with the intestinal contraction. Results obtained through the experiments were summarized as follows: 1. Acetylcholine(ACh) exhibited biphasic dose-response curves: initial ACh-induced dose dependent contractions were observed in pM levels but followed by decreased response in in-between concentration levels. Dose dependent contractions reappeared in ${\mu}M$ level. The peaks in pM and ${\mu}M$ levels appeared in $10^{-13}M$ and $3{\times}10^{-5}M$, respectvely. 2. Carbachol(CaCh) exhibited dose dependent contractions from $10^{-9}M$ to $10^{-5}M$, and its $pD_2$ values were higher than those of ACh($5.60{\pm}0.11$). ACh and CaCh exhibited equiactive contractions. Nicotine had no effects on contractile responses of Israeli carp intestine. 3. ACh-induced responses were inhibited by atropine($K_1:7{\times}10^{-8}M$), a muscarinic antagonist, in a non-competitive manner. But CaCh-induced responses were inhibited by both antimuscarinic atropine($pA_2:9.52{\pm}0.14$) and selective $M_2$ antagonistic 4-DAMP($pA_2:8.16{\pm}0.09$), in competitive manners. Nicotine receptor antagonistic decamethonium and hexamethonium had no effects on ACh-and CaCh-induced contractions. Therefore, the cholinergic receptor related to intestinal motility of Israeli carp was assumed as $M_2$ type. 4. In Israeli carp intestine, 5-HT (serotonin) exhibited dose dependent contractions in concentration range from $10^{-8}M$ to $10^{-5}M$. The maximal responses, however, were corresponded to about 50% of those of ACh or CaCh. 5-HT induced contractions were inhibited by $5-HT_2$ antagonistic ketanserin ($K_1: 7.8{\times}10^{-4}M$) in a non-competitive manner, but not by both of anti $5-HT_1$, spiperone and anti $5-HT_3$, MDL-72222. Hence, $5-HT_2$ receptors are suggested to be existed in Isreli carp intestine.

• Proceedings of the Ginseng society Conference
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• 1998.06a
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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.

• Journal of Ginseng Research
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• v.35 no.2
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• pp.176-190
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• 2011

There seems to be some controversy about the effect of total ginseng saponin (TGS) on the secretion of catecholamines (CA) from the adrenal gland. Therefore, the present study aimed to determine whether TGS can affect the CA release in the perfused model of the adrenal medulla isolated from spontaneously hypertensive rats (SHRs). TGS (15-150 ${\mu}g/mL$), perfused into an adrenal vein for 90 min, inhibited the CA secretory responses evoked by acetylcholine (ACh, 5.32 mM) and high $K^+$ (56 mM, a direct membrane depolarizer) in a dose- and time-dependent fashion. TGS (50 ${\mu}g/mL$) also time-dependently inhibited the CA secretion evoked by 1.1-dimethyl-4 -phenyl piperazinium iodide (DMPP; 100 ${\mu}M$, a selective neuronal nicotinic receptor agonist) and McN-A-343 (100 ${\mu}M$, a selective muscarinic M1 receptor agonist). TGS itself did not affect basal CA secretion (data not shown). Also, in the presence of TGS (50 ${\mu}g/mL$), the secretory responses of CA evoked by veratridine (a selective $Na^+$ channel activator (50 ${\mu}M$), Bay-K-8644 (an L-type dihydropyridine $Ca^{2+}$ channel activator, 10 ${\mu}M$), and cyclopiazonic acid (a cytoplasmic $Ca^{2+}$-ATPase inhibitor, 10 ${\mu}M$) were significantly reduced, respectively. Interestingly, in the simultaneous presence of TGS (50 ${\mu}g/mL$) and N${\omega}$-nitro-L-arginine methyl ester hydrochloride [an inhibitor of nitric oxide (NO) synthase, 30 ${\mu}M$], the inhibitory responses of TGS on the CA secretion evoked by ACh, high $K^+$, DMPP, McN-A-343, Bay-K-8644, cyclopiazonic acid, and veratridine were considerably recovered to the extent of the corresponding control secretion compared with the inhibitory effect of TGS-treatment alone. Practically, the level of NO released from adrenal medulla after the treatment of TGS (150 ${\mu}g/mL$) was greatly elevated compared to the corresponding basal released level. Taken together, these results demonstrate that TGS inhibits the CA secretory responses evoked by stimulation of cholinergic (both muscarinic and nicotinic) receptors as well as by direct membrane-depolarization from the isolated perfused adrenal medulla of the SHRs. It seems that this inhibitory effect of TGS is mediated by inhibiting both the influx of $Ca^{2+}$ and Na+ into the adrenomedullary chromaffin cells and also by suppressing the release of $Ca^{2+}$ from the cytoplasmic calcium store, at least partly through the increased NO production due to the activation of nitric oxide synthase, which is relevant to neuronal nicotinic receptor blockade, without the enhancement effect on the CA release. Based on these effects, it is also thought that there are some species differences in the adrenomedullary CA secretion between the rabbit and SHR.

• Animal Bioscience
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• v.36 no.2
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• pp.200-208
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• 2023

Objective: Muscle acetylcholine receptors have five alpha subunits (α, β, δ, ε, or γ), and cholinergic receptor nicotinic gamma subunit (CHRNG) is the γ subunit. It may also play an essential role in biological processes, including cell differentiation, growth, and survival, while the role of CHRNG has not been studied in the literature. Therefore, the purpose of this study is to clarify the effect of CHRNG on the proliferation and differentiation of bovine preadipocytes. Methods: We constructed a CHRNG overexpression adenovirus vector and successfully overexpressed it on bovine preadipocytes. The effects of CHRNG on bovine preadipocyte proliferation were detected by Edu assay, cell counting Kit-8 (CCK-8), real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), Western blot and other techniques. We also performed oil red O, RT-qPCR, Western blot to explore its effect on the differentiation of preadipocytes. Results: The results of Edu proliferation experiments showed that the number of EDU-positive cells in the overexpression group was significantly less. CCK-8 experiments found that the optical density values of the cells in the overexpression group were lower than those of the control group, the mRNA levels of proliferating cell nuclear antigen (PCNA), cyclin A2 (CCNA2), cyclin B1 (CCNB1), cyclin D2 (CCND2) decreased significantly after CHRNG gene overexpression, the mRNA levels of cyclin dependent kinase inhibitor 1A (CDKN1A) increased significantly, and the protein levels of PCNA, CCNB1, CCND2 decreased significantly. Overexpression of CHRNG inhibited the differentiation of bovine preadipocytes. The results of oil red O and triglyceride determination showed that the size and speed of lipid droplets accumulation in the overexpression group were significantly lower. The mRNA and protein levels of peroxisome proliferator activated receptor gamma (PPAR class="checkNonKBPoint">γ), CCAAT enhancer binding protein alpha (CEBPα), fatty acid binding protein 4 (FABP4), fatty acid synthase (FASN) decreased significantly. Conclusion: Overexpression of CHRNG in bovine preadipocytes inhibits the proliferation and differentiation of bovine preadipocytes.

• The Korean Journal of Pharmacology
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• v.25 no.1
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• pp.43-51
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• 1989

Responsiveness of muscarinic and alpha adrenoceptor activation on endothelial cells was studied in isolated canine renal artery rings. Ach (10-100 nM), dose dependently, relaxes endothelial intact rings precontracted with phenylephrine ($IC_{50}$ of Ach was 34.5 nM). Selective mechanical destruction of the endothelium transformed the activity of this substance from vasodilatation to vasoconstriction. Acetylcholine induced relaxations could be selectively inhibited competitively by atropine, but could not be inhibited by cyclooxygenase inhibitor. Methylene blue, however, an inhibitor of soluble guanylate cyclase activity, inhibited Ach as well as sodium nitroprusside (SNP) induced relaxation. Relaxation produced by prostacyclin was not modified by methylene blue. On the other hand, alpha adrenoceptor agonist did not relax but contract canine renal artery rings possessing an intact intima precontracted with U-46619. Clonidine, however, selective alpha-2 adrenergic agonist, is more susceptible than phenylepherine, selective alpha-1 adrenergic agonist, to the inhibitory effect of contraction. These results suggest that in canine renal artery rings, 1) muscarinic receptor is responsible for releasing endothelium dependent relaxation factor (EDRF). 2) alpha-1 and alpha-2 adrenergic receptors are present in canine renal artery. 3) relaxation via EDRF is antagonized by methylene blue, providing further evidence that EDRF acts through a cGMP mechanism.

• The Korean Journal of Pharmacology
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• v.32 no.1
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• pp.13-21
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• 1996

Intracellular calcium concentration ($[Ca^{2+}]_i$) may play a crucial role in a variety of neuronal functions. Here we report that in primary culture of mouse cerebellar granule cells nicotinic acetylcholine receptors (nAChRs) are expressed in a specific developmental stage and involved in the regulation of intracellular calcium homeostasis. Nicotine-mediated calcium responses were measured using $^{45}Ca^{2+}$ or fluorometrically using the calcium-sensitive fluorescent dye fura-2. Maximal uptake of $^{45}Ca^{2+}$ evoked by nicotine in mouse cerebellar granule cells were revealed $8{\sim}12$ days in culture. In contrast, nicotine did not alter the basal $^{45}Ca^{2+}$ uptake in cultured glial cells. In cerebellar granule cells nicotine-evoked $^{45}Ca^{2+}$ uptake was largely blocked by the NMDA receptor antagonists. Glutamate pyruvate transaminase (GPT). which removes endogenous glutamate, also prevented nicotine effects, implying the indirect involvement of glutamate in nicotine-mediated calcium responses. Fluorometric studies using fura-2 showed two phases of nicotine-evoked $[Ca^{2+}]_i$ rises: the initial rising phase and the later plateau phase. Interestingly, the NMDA receptor antagonists and GPT appeared to inhibit only the later plateau phase of nicotine-evoked $[Ca^{2+}]_i$ rises. The present results imply that nicotine mediated $^{45}Ca^{2+}$ uptake and $[Ca^{2+}]_i$ rises are attributed to the calcium fluxes through both nAchRs and NMDA receptors in a time-dependent manner. Consequently, nAChRs may play an important role in neuronal development by being expressed in a specific developmental stage and regulating the intracellular calcium homeostasis.