• 대한수의학회지
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• 제28권1호
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• pp.37-47
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• 1988

Xylazine hydrochloride is a widely used analgesic, sedative and muscle relaxant agent in veterinary clinic. Yohimbine hydrochloride and 4-aminopyridine are known as antagonists of xylazine hydrochloride. This paper was investigated to know that the effect of xylazine hydrochloride, yohimbine hydrochloride and 4-aminopyridine, and that whether or not antagonism of yohimbine hydrochloride and 4-aminopyridine to xylazine hydrochloride-induced effect on gizzard motility in chicken. The results were as follows. 1. After xylazine hydrochloride administration, the gizzard motility in chicken was instantly inhibited in relaxation state, and this state was prolonged in proportion to increase of dose. 2. After yohimbine hydrochloride administration, the gizzard motility in chicken showed increase of contractile frequency. 3. After 4-aminopyridine administration, the gizzard motility in chicken was gradually recovered next to decrease of contractile amplitude and frequency. 4. After the combination of yohimbine hydrochloride and 4-aminopyridine administration, the gizzard motility in chicken showed increase of amplitude and radical increase of frequency. 5. After xylazine hydrochloride administration, the relaxation time was shortened by yohimbine hydrochloride, 4-aminopyridine and the combination of yohimbine hydrochloride and 4-aminopyridine. In conclusion, the gizzard motility in chicken was inhibited by xylazine hydrochloride, and this effect was antagonized by the combination of yohimbine hydrochloride and 4-aminopyridine.

• 대한수의학회지
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• 제30권1호
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• pp.113-121
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• 1990

The present study was undertaken to determine the effect of xylazine-pentobarbital anesthesia on the gastroduodenal transit time of barium sulfate and whether this condition can be antagonized by yohimbine, 4-aminopyridine and yohimbine+4-aminopyridine in dogs. Xylazine-pentobarbital anesthesia prolonged the gastroduodenal transit time to $121.50{\pm}21.25$ minutes compared with $5.25{\pm}0.90$ minutes of control. Yohimbine and yohimbine+4-aminopyridine reversed $121.50{\pm}21.25$ minutes of transit time of anesthetized dog to $25.25{\pm}6.83$ and $63.25{\pm}15.69$ minutes, respectively. 4-aminopyridine alone, $115.75{\pm}$18.35 minutes, was not effective in reversing the xylazine-pentobarbital-induced prolongation of gastroduodenal transit time. Yohimbine was the most effective for reversal of xylazine-pentobarbital-induced prolongation of gastroduodenal transit time in dogs.

• 한국응용과학기술학회지
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• 제21권3호
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• pp.246-251
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• 2004

Diazotization of three aminopyridine such as 3-amino-2-chloropyridine, 5-amino-2-chloropyridine, and 3-aminopyridine were investigated. Preparation of pyridinediazonium tetrafluoroborates were carried out employing two different methods. Diazotization of aminopyridines with a chlorine substituent in the pyridine ring were conducted in acidic aqueous solution with sodium nitrite in 70% and 74% yields respectively. 3-Pyridinediazonium tetrafluoroborate without any ring subsituent was unstable in an aquous solution and the diazotiation of 3-aminopyridine was proceded in an anhydrous methylene chloride-etherial $BF_3$ solution with tert-butyl nitrite in 40% yield.

• 대한화학회지
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• 제57권3호
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• pp.341-351
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• 2013

Zn(II), Cd(II) and Hg(II) complexes with a general composition[$M(L)_2(X)_2$], where L=4-aminopyridine (4AP) and $X=NO_2{^-}$ were prepared under microwave irradiation. The metal complexes were characterized by elemental analyses, molar conductance, IR, Far-IR, electronic, NMR ($^1H$, $^{13}C$), XPS spectral and thermal studies. The spectroscopic studies reveal the composition, different modes of bonding, electronic transition, different chemical environment of C and H atoms and the electronic state of the metal atoms. On the basis of the characterization data, tetrahedral geometry is suggested for all the complexes. The free ligand (4-aminopyridine) and their metal complexes were screened against phytopathogenic fungi and bacteria in vitro and the activities were compared.

• 대한화학회지
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• 제57권6호
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• pp.712-720
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• 2013

Microwave assisted syntheses of Zn(II), Cd(II) and Hg(II) complexes with 3-aminopyridine (3AP) and nitrite ($NO_2{^-}$) ions have been reported. The metal complexes were characterized by elemental analyses, molar conductance, IR, Far-IR, electronic, NMR ($^1H$, $^{13}C$), thermal and electron impact mass spectral studies. The spectroscopic studies reveal the composition, the nature of nitrite ligand in the complexes, electronic transitions, chemical environments of C and H atoms thermal degradation of the complexes. On the basis of characterization data, distorted tetrahedral geometry is suggested for Zn(II), Cd(II) and Hg(II) complexes. The organic ligand (3AP) and their metal complexes were screened against gram negative pathogenic bacteria and fungi in vitro. The results are compared with our previous report J. Korean Chem. Soc. 2013, 57, 341 on 4-aminopyridine and nitrite ion complexes of the same metal ions.

• Bulletin of the Korean Chemical Society
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• 제33권2호
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• pp.535-540
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• 2012

A series of benzamide-based histone deacetylases (HDACs) inhibitors possessing N-(aminopyridine) residue as the zinc binding site of HDAC were synthesized and evaluated. Among these derivatives, compounds with N-(2-amino-4-pyridine) benzamide moiety have been found as the most potent ones. Moreover, introduction of appropriate substituents on the terminal aryl group acting as the surface-recognition domain could significantly improve the antiproliferative activity. In particular, the compound 4k possessed favorable pharmacokinetic characteristics and exhibited potent antitumor activity on xenograft model in mice at well tolerated doses, thus suggesting a good therapeutic index.

• Elastomers and Composites
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• 제12권1호
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• pp.27-32
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• 1977

The kinetics of azo-coupling reaction of N-acetyl-H-acid (1-acetamino-8-hydroxynaphthalene-3, 6-disulfonic acid) with several heterocyclic diasonium compounds such as diazotiged 3-aminopyridine, 3-aminoquinoline, 8-aminoauinoline and aniline was studied. It was found that reactions proceeded at remarkably different rate. Reaction rate was in increasing order; 3-aminopyridine, 3-aminoquinoline, 8-aminoauinoline and aniline. And the activation energies were 9.62, 10.10, 10.39, 10.70 Kcal/mole, respectively. Especially, the rate constant of 3-aminopyridine was 100 times larger than that of benzene diasonium compound even in strong acidity. Hammett plot was also made of the rate constants obtained against the heterocyclic substituent constants reported in the literature. A good linear relationship was obtained and the reaction constant of N-acetyl H-acid was calculated to be 3.14.

• Journal of Pharmaceutical Investigation
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• 제35권6호
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• pp.453-460
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• 2005

4-Aminopyridine (AP) is a potassium channel blocker used in the treatment of neurological disorders such as multiple sclerosis and Alzheimer disease. AP‘s window of therapeutic effect appears to correlate with its plasma halflife (3.5 hours). It demonstrates pH-dependent solubility because of a weakly basic drug. In addition, the resulting release from conventional matrix tablets decreases with increasing pH-milieu of the gastrointestinal tract. The aim of this study is to design sustained release matrix tablet containing AP, overcoming this problem. $Eudragit^{\circledR}$ L 100 (EuL) and sodium alginate were used in an effort to achieve pH independent drug release. The effect of sodium alginate and EuL on drug release from matrix tablet was investigated. The drug release behavior from the different tablets was analyzed by $t_{20%},\;t_{40%},\;t_{60%}$, The exponential diffusion coefficient n, kinetic constant K were calculated according to the Korsmeyer-Peppas equation. The drug release from matrix tablets prepared with sodium alginate was decreased with increasing the content of sodium alginate in pH 7.4 while there is no significant difference in pH 1.2. The exponent n values were determined to be approximately 0.5 and 0.8 respectively, in both pH 1.2 and 7.4. These values indicate diffusion-based anomalous mechanism and erosion-based anomalous mechanism, respectively. The drug release from sodium alginate matrix tablets prepared with solid dispersion of EuL containing drug showed a slow drug release in an acidic medium and a more fast drug release in phosphate medium, compared with sodium alginate matrix tablets prepared with physical mixture. These results may be attributed to the gel forming ability of sodium alginate and pH dependent solubility of EuL. Therefore, sustained-release AP matrix tablets using sodium alginate and EuL were successfully prepared.

• The Korean Journal of Physiology and Pharmacology
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• 제4권6호
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• pp.463-469
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• 2000

It has been well known that 4-aminopyridine (4-AP) has an excitatory effect on vascular smooth muscle due to causing membrane depolarization by blocking $K^+-channel$. However, we observed that 4-AP had an inhibitory effect on the mesenteric artery of rat. Therefore, we investigated the mechanism of 4-AP-induced vasorelaxation. The mesenteric arcuate artery and its branches were isolated and cut into ring. The ring segment was immersed in HEPES-buffered solution and its isometric tension was measured. 4-AP $(0.1{\sim}10\;mM)$ induced a concentration-dependent relaxation, which was unaffected by NO synthase inhibitor, $N^G-nitro-L-arginine$ methylester $(100\;{\mu}M)$ or soluble guanylate cyclase inhibitor, methylene blue $(100\;{\mu}M).$ Glibenclamide $(100\;{\mu}M)$, ATP-sensitive $K^+$ channel blocker, did not exert any effect on the 4-AP-induced vasorelaxation. 4-AP relaxed the sustained contraction induced by 100 mM $K^+$ or $Ca^{2+}$ ionophore, A23187 $(100\;{\mu}M)$ in a dose-dependent manner. In addition, 4-AP significantly decreased the phasic contractile response to norepinephrine in the absence of extracellular $Ca^{2+}$. However, 4-AP did not block the $^{45}Ca$ influx of rat aorta. From the above results, we suggest that 4-AP may not block the $Ca^{2+}$ influx through $Ca^{2+}-channel,$ but act as a nonspecific vasorelaxant in arterial smooth muscle.

• 전기화학회지
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• 제17권1호
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• pp.30-36
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• 2014

산화/환원 매개체는 혈당 센서의 구성에서 전극과 효소 반응의 전자 전달 매개체로서 중요한 역할을 담당한다. 본 연구에서는 기존의 산화/환원 매개체보다 전자 전달 반응이 용이하며, 높은 민감도를 위해 페레이트에 아닐린을 결합시켜, 1차 아민기를 갖는 $Fe(CN)_5$-aminopyridine를 합성하였다. 합성된 $Fe(CN)_5$-aminopyridine 는 순환 전압 전류 법과 분광학적 방법을 이용하여 합성 결과를 확인하였다. 합성된 물질과 포도당을 측정하기 위한 당 탈 수소 효소를 ITO 전극위에 고정시켜 효소전극을 제작하였고, 또한 신호 증폭을 위하여 금 나노 입자를 함께 고정시켰다. 금 나노 입자가 고정된 효소 전극은 그렇지 않은 전극에 비해 약 2배 가량의 전류 밀도가 증가함을 확인하였다. 만들어진 효소 전극에서 포도당의 농도 별 산화 촉매 전류를 순환 전압 전류 법으로 측정한 결과 0.4 V (vs. Ag/AgCl)에서 전기적 신호가 발생되었으며, 포도당 0~10 mM의 농도 범위에서 전기적 신호가 선형 증가함을 확인할 수 있었다.