• 한국산학기술학회논문지
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• 제17권2호
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• pp.123-128
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• 2016

본 연구는 안면부 신경병증 통증 모델에서 간극결합을 분리하는 Carbenoxolone(CBX)과 P2X 수용체의 길항제(iso-PPADS)의 진통작용을 확인하고자 수행되었다. 실험동물은 Sprague-Dawley계 수컷 흰쥐(240~280g)를 사용하였으며, 안면부 신경병증 통증을 유발하기 위해 흰쥐의 하악 왼쪽 두 번째 어금니를 발거하고, 아랫 이틀신경의 손상을 유도하기 위해 소형 치과용 임플란트를 식립하였다. CBX를 복강으로 하루 2번 투여 했을 때, 25ug/kg에서 유의한 진통반응이 나타났다(p<0.05). iso-PPADS 역시 복강으로 하루 2번 투여 했을 때, 25ug/kg에서 유의한 진통반응이 나타났다(p<0.05). 두 약물의 각각의 효과가 나타나지 않은 저 농도에서 함께 투여하였을 때, CBX 1ug/kg, iso-PPADS 2.5ug/kg를 투여 시 유의한 진통 효과가 나타났다(p<0.05). 저 농도의 CBX를 이용한 간극결합의 차단과 저 농도의 P2X 수용체의 길항제를 함께 투여 시 구강 안면신경병증통증기전에서 통증을 억제하는 효과를 확인할 수 있었다. 이러한 결과를 통하여 CBX를 이용한 간극결합의 차단과 P2X 수용체의 길항제의 투여가 안면부 통증조절에 중요한 역할을 담당할 것으로 사료된다.

• Clinical and Experimental Reproductive Medicine
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• 제30권4호
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• pp.269-280
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• 2003

Objective: We reported the overcoming effect of $Ni^{2+}$ on the in vitro 2-cell block of mouse embryos. In this study, we aim to investigate whether $Ni^{2+}$ should induce intracellular $Ca^{2+}$ transient in the mouse embryos. Materials and Methods: Embryos were collected at post hCG 32hr from the oviduct of the ICR mouse and cultured in M2 medium omitted phenol red. Intracellular $Ca^{2+}$ was checked by using a confocal laser scanning microscope and fluo-3AM by using various intracellular $Ca^{2+}$ antagonists. Results: In 1mM $Ni^{2+}$ treated medium which contained $Ca^{2+}$(1.71mM), 75.7% of the embryos showed $[Ca^{2+}]i$ transient about 200 sec later. In the $Ca^{2+}$-free medium, 69.8% of the embryos showed $[Ca^{2+}]i$ transient. In U73122, phospholipaseC(PLC) inhibitor (5uM, 10min) pretreated group, 33.3% of the embryos showed $[Ca^{2+}]i$ transient. Heparine, inositol 1, 4, 5-triphosphate receptor(IP3R) antagonist preinjected embryos showed no response with 1mM $Ni^{2+}$. In danthrolene treatment, ryanodine receptor(RyR)-antagonist, 43% embryos showed $[Ca^{2+}]i$ transient but they showed delayed response about 340sec in the presence of $Ca^{2+}$. Conclusions: Summing up the above results, $Ni^{2+}$ seems to induce $Ca^{2+}$-release from the $Ca^{2+}$-store even in the $Ca^{2+}$-free medium. IP3 receptors of the mouse 2-cell embryos might have an essential role for the intracellular $Ca^{2+}$ increase by $Ni^{2+}$.

• Biomolecules & Therapeutics
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• 제18권3호
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• pp.316-320
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• 2010

Pruritus is one of major symptoms in atopic dermatis. The pathophysiological mechanism of pruritus is unclear. The search for pruritogen is important in elucidating the pathophysiological mechanism of pruritus in atopic dermatitis. Glucosylsphingosine (Gsp) is upregulated in the strateum corneum of atopic dermatitis patients. We investigated to determine whether Gsp induces itch-scratch responses (ISRs) in mice. Intradermal administration of Gsp induces ISRs. Gsp dose-dependently induced scratching response at 50-500 nmol/site range. Pretreatment with naltrexone, an opioid $\mu$ receptor antagonist, and capsaicin, a TrpV1 receptor agonist, inhibited Gsp-induced ISRs. Additionally, Gsp-induced ISRs were also suppressed by cyproheptadine, an antagonist of serotonin receptor. These findings suggest that Gsp-induced scratching might be at least partly mediated by capsaicin-sensitive primary afferents, and the opioids receptor systems might be involved in transmission of itch signaling in the central nervous system. Furthermore, our findings suggest that Gsp-induced ISRs may be attributable to the serotonin-mediated pathways and Gsp is not any more one of byproducts of abnormal skin barrier but can lead to induce pruritus, one of typical symptoms of atopic dermatitis.

• The Korean Journal of Physiology and Pharmacology
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• 제21권4호
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• pp.385-395
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• 2017

Vasoconstrictive properties of sympathomimetic drugs are the basis of their widespread use as decongestants and possible source of adverse responses. Insufficiently substantiated practice of combining decongestants in some marketed preparations, such are those containing phenylephrine and lerimazoline, may affect the overall contractile activity, and thus their therapeutic utility. This study aimed to examine the interaction between lerimazoline and phenylephrine in isolated rat aortic rings, and also to assess the substrate of the obtained lerimazoline-induced attenuation of phenylephrine contraction. Namely, while lower concentrations of lerimazoline ($10^{-6}M$ and especially $10^{-7}M$) expectedly tended to potentiate the phenylephrine-induced contractions, lerimazoline in higher concentrations ($10^{-4}M$ and above) unexpectedly and profoundly depleted the phenylephrine concentration-response curve. Suppression of NO with NO synthase (NOS) inhibitor $N^w$-nitro-L-arginine methyl ester (L-NAME; $10^{-4}M$) or NO scavanger $OHB_{12}$ ($10^{-3}M$), as well as non-specific inhibition of $K^+$-channels with tetraethylammonium (TEA; $10^{-3}M$), have reversed lerimazoline-induced relaxation of phenylephrine contractions, while cyclooxygenase inhibitor indomethacin ($10^{-5}M$) did not affect the interaction between two vasoconstrictors. At the receptor level, non-selective 5-HT receptor antagonist methiothepin reversed the attenuating effect of lerimazoline on phenylephrine contraction when applied at $3{\times}10^{-7}$ and $10^{-6}M$, but not at the highest concentration ($10^{-4}M$). Neither the 5-$HT_{1D}$-receptor selective antagonist BRL 15572 ($10^{-6}M$) nor 5-$HT_7$ receptor selective antagonist SB 269970 ($10^{-6}M$) affected the lerimazoline-induced attenuation of phenylephrine activity. The mechanism of lerimazoline-induced suppression of phenylephrine contractions may involve potentiation of activity of NO and $K^+$-channels and activation of some methiothepin-sensitive receptors, possibly of the 5-$HT_{2B}$ subtype.

• The Korean Journal of Physiology and Pharmacology
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• 제18권1호
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• pp.41-46
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• 2014

The possible roles of spinal histamine receptors in the regulation of the blood glucose level were studied in ICR mice. Mice were intrathecally (i.t.) treated with histamine 1 (H1) receptor agonist (2-pyridylethylamine) or antagonist (cetirizine), histamine 2 (H2) receptor agonist (dimaprit) or antagonist (ranitidine), histamine 3 (H3) receptor agonist (${\alpha}$-methylhistamine) or antagonist (carcinine) and histamine 4 (H4) receptor agonist (VUF 8430) or antagonist (JNJ 7777120), and the blood glucose level was measured at 30, 60 and 120 min after i.t. administration. The i.t. injection with ${\alpha}$-methylhistamine, but not carcinine slightly caused an elevation of the blood glucose level. In addition, histamine H1, H2, and H4 receptor agonists and antagonists did not affect the blood glucose level. In D-glucose-fed model, i.t. pretreatment with cetirizine enhanced the blood glucose level, whereas 2-pyridylethylamine did not affect. The i.t. pretreatment with dimaprit, but not ranitidine, enhanced the blood glucose level in D-glucose-fed model. In addition, ${\alpha}$-methylhistamine, but not carcinine, slightly but significantly enhanced the blood glucose level D-glucose-fed model. Finally, i.t. pretreatment with JNJ 7777120, but not VUF 8430, slightly but significantly increased the blood glucose level. Although histamine receptors themselves located at the spinal cord do not exert any effect on the regulation of the blood glucose level, our results suggest that the activation of spinal histamine H2 receptors and the blockade of spinal histamine H1 or H3 receptors may play modulatory roles for up-regulation and down-regulation, respectively, of the blood glucose level in D-glucose fed model.

• The Korean Journal of Physiology and Pharmacology
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• 제7권2호
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• pp.59-63
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• 2003

The medial vestibular nucleus (MVN) neurons are controlled by excitatory synaptic transmission from the vestibular afferent and commissural projections, and by inhibitory transmission from interneurons. Spontaneous synaptic currents of MVN neurons were studied using whole cell patch clamp recording in slices prepared from 13- to 17-day-old rats. The spontaneous inhibitory postsynaptic currents (sIPSCs) were significantly reduced by the $GABA_A$ antagonist bicuculline ($20{\mu}M$), but were not affected by the glycine antagonist strychnine ($1{\mu}M$). The frequency, amplitude, and decay time constant of sIPSCs were $4.3{\pm}0.9$ Hz, $18.1{\pm}2.0$ pA, and $8.9{\pm}0.4$ ms, respectively. Spontaneous excitatory postsynaptic currents (sEPSCs) were mediated by non-NMDA and NMDA receptors. The specific AMPA receptor antagonist GYKI-52466 ($50{\mu}M$) completely blocked the non-NMDA mediated sEPSCs, indicating that they are mediated by an AMPA-preferring receptor. The AMPA mediated sEPSCs were characterized by low frequency ($1.5{\pm}0.4$ Hz), small amplitude ($13.9{\pm}1.9$ pA), and rapid decay kinetics ($2.8{\pm}0.2$ ms). The majority (15/21) displayed linear I-V relationships, suggesting the presence of GluR2-containing AMPA receptors. Only 35% of recorded MVN neurons showed NMDA mediated currents, which were characterized by small amplitude and low frequency. These results suggest that the MVN neurons receive excitatory inputs mediated by AMPA, but not kainate, and NMDA receptors, and inhibitory transmission mediated by $GABA_A$ receptors in neonatal rats.

• Biomolecules & Therapeutics
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• 제28권4호
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• pp.328-336
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• 2020

Diabetes mellitus affects the colonic motility developing gastrointestinal symptoms, such as constipation. The aim of the study was to examine the role of intracellular signaling pathways contributing to colonic dysmotility in diabetes mellitus. To generate diabetes mellitus, the rats were injected by a single high dose of streptozotocin (65 mg/kg) intraperitoneally. The proximal colons from both normal and diabetic rats were contracted by applying an electrical field stimulation with pulse voltage of 40 V in amplitude and pulse duration of 1 ms at frequencies of 1, 2, 4, and 6 Hz. The muscle strips from both normal rats and rats with diabetes mellitus were pretreated with different antagonists and inhibitors. Rats with diabetes mellitus had lower motility than the control group. There were significant differences in the percentage of inhibition of contraction between normal rats and rats with diabetes mellitus after the incubation of tetrodotoxin (neuronal blocker), atropine (muscarinic receptor antagonist), prazosin (α₁ adrenergic receptor antagonist), DPCPX (adenosine A1 receptor antagonist), verapamil (L-type Ca²⁺ channel blocker), U73122 (PLC inhibitor), ML-9 (MLCK inhibitor), udenafil (PDE₅ inhibitor), and methylene blue (guanylate cyclase inhibitor). The protein expression of p-MLC and PDE₅ were decreased in the diabetic group compared to the normal group. These results showed that the reduced colonic contractility resulted from the impaired neuronal conduction and decreased muscarinic receptor sensitivity, which resulted in decreased phosphorylation of MLC via MLCK, and cGMP activity through PDE₅.

• The Korean Journal of Physiology and Pharmacology
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• 제1권5호
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• pp.467-475
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• 1997

Although one of the major physiological functions of taurine(2-aminoethanesulfonic acid) is the inhibitory action on the central nervous system(CNS), the mechanism of taurine in controlling the neuronal excitation in the CNS has been in controversy. Electrically evoked pEPSP and spontaneous activity induced by the perfusion of low $Mg^{++}-ACSF$ were recorded in the CA1 pyramidal cell layer of the hippocampal slice. To test the inhibitory effect of taurine on spontaneous responses, taurine was treated for 2 min at various concentrations(1 mM-10 mM). Taurine reduced the spontaneous activity by 22.2% at 1 mM, and 100% at 2 mM in low $Mg^{++}-ACSF$. Evoked response was induced by electrical stimulation of Schaffer collateral-commissural fibers. Taurine reduced the evoked response by 11.68% at 3 mM, and 24.25% at 5 mM. Even 20 mM of taurine reduced the evoked response only by 24 % after 5 min treatment. That is, the inhibitory efficacy was much higher in spontaneous activity than in evoked response. The $GABA_A$ receptor antagonist, 100 uM bicuculline, blocked the inhibitory action of taurine, while $GABA_B$ receptor antagonist, 700 uM phaclofen, did not. Taurine blocked the spontaneous activity in the presence of CNQX, and did not block the electrically evoked responce in the presence of APV. The results suggest that taurine causes hyperpolarization in the cell by binding to $GABA_A$ receptor and preferentially attenuates NMDA receptor-mediated hyperexcitation, leaving synaptic transmission unmodified.

• 생명과학회지
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• 제20권7호
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• pp.969-976
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• 2010

피리딜 이미다졸 시리즈의 비펩타이드 안지오텐신 수용체 리간드로 새롭게 개발된 KR-31125에 대한 생체 내활성을 동물모델에서 검증하였다. 척수장애 동물모델에서 KR-31125는 비대칭 농도의존적으로 로자탄보다 18배 이상의 경쟁적인 혈압강하 효과를 나타내었으며, 기타 수용체 촉진제들의 영향을 받지 않았다. 안지오텐신으로 유도된 정상혈압 쥐모델에서는 대조화합물인 로자탄과 비교하여 경구효과는 동등하였으나 더 빠른 초기효과가 관찰되었다. 또한 신성고혈압 쥐모델에서 KR-31125는 로자탄보다 3배 이상의 지속형 혈압강하 효과를 나타내었고, 이뇨제를 투여하여 레닌을 활성화시킨 개실험 모델에서 KR-31125는 로자탄보다 20배 이상의 지속적인 경구혈압강하 효과를 나타내었다. 이러한 KR-31125의 생체 내 활성특징은 대사물질을 통하여 효과를 발휘하는 로자탄과 달리 동일물질의 효과에 의한 것으로 고혈압 및 혈관질환과 깊은 관련이 있는 안지오텐신 조절시스템에 대한 세포영상, 비침투성 진단등의 도구물질로서 가능성이 높을 것으로 판단된다.

• 생명과학회지
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• 제20권6호
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• pp.831-837
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• 2010

KR-31125는 피리딜 이미다졸 시리즈 화합물로서 비펩타이드 안지오텐신 수용체 길항제로 새롭게 개발되었다. 동위원소 리간드를 사용한 재조합 수용체 결합실험과 기능성 토끼혈관실험 결과 기존 의약인 로자탄과 동등수준의 수용체 길항효과를 나타내었다. 이러한 KR-31125의 특징들은 제 1형 안지오텐신 수용체에 특이적으로 나타났으며($IC_{50}$: $19.72{\pm}2.65\;nM$), 표준물질에 대한 대조실험 결과 제 2형 안지오텐신 수용체에 대한 결합친화력은 발견되지 않았다. 기능성 혈관실험에서 KR-31125가 안지오텐신에 의한 혈관수축 효과를 경쟁적으로 저하시켰지만 표준물질인 로자탄과는 달리 농도가 증가함에 따라 30-80% 정도의 최대 수축효과 감소가 관찰되어 로자탄과는 다른 분자작용 기전을 가진다고 판단된다. 제 1형 안지오텐신 수용체에 선택적으로 작용하는 것으로 나타난 KR-31125는 레닌-안지오텐신-알도스테론 시스템에 대한 연구 및 진단에 폭 넓게 활용될 수 있는 표지자 화합물로 가능성을 넓혀 줄 수 있을 것이라고 판단된다.