• Biomolecules & Therapeutics
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• 제12권4호
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• pp.215-220
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• 2004

In an attempt to develop new anti-diabetic agents, a series of aryloxypropanolamine derivatives was synthesized to serve as ${\beta}_3$ adrenoceptor agonists. Among these derivatives, 1-{1-methyl-3-[4-(2-methyl-2H-1,2,3,4-tetrazol-5-yl)phenyl]propylamino}-3-phenoxy-2-propanol (KR60886) possessed a high affinity for the ${\beta}_3$ adrenoceptor (Ki = 28 nM) and moderate affinities for ${\beta}_1$ and ${\beta}_2$ adrenoceptors (Ki = 95 nM and 100 nM, respectively). In addition, KR60886 stimulated cAMP production with an EC$_{50}$ of 0.4 ${\mu}M$, confirming its agonistic activity for the ${\beta}_3$ adrenoceptor. In vivo activities of KR60886 were examined by using a fat-fed/streptozotocin (STZ)-treated rat model and the ob/ob mouse model. Oral administration of KR60886 (10 mg/kg) for 3 days (b.i.d.) to fat-fed/STZ-treated rats significantly lowered plasma glucose levels and reduced plasma free fatty acid concentrations. Similarly, KR60886 treatment (10 mg/kg/day for 7 d) resulted in a reduction of plasma glucose concentrations in ob/ob mice. The present study suggests that KR60886 is a potent ${\beta}_3$ receptor agonist with in vivo anti-diabetic properties.

• The Korean Journal of Physiology
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• 제27권1호
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• pp.27-35
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• 1993

Effects of the endothelium on the contractile responses to norepinephrine (NE) were investigated in isolated helical strips of the proximal and distal coronaries artery of pigs. The helical strips were immersed in Tris-buffered Tyrode's solution equilibrated with 100% $O_2$ at $35^{\circ}C$ and its isometric tension was measured. NE relaxed the strips precontracted with acetylcholine from both the proximal and distal coronary artery. NE-induced relaxation, which might be induced mainly by $\beta$-adrenoceptor function was dominant in the distal coronary arteries. NE-induced relaxation was converted to a contraction after $\beta$-adrenoceptor blockade with propranolol $(3{\times}10^{-6}M)$. ${\alpha}$-adrenoceptor-mediated contraction by NE was greater in the proximal coronary artery than the distal coronary artery. Quantitatively, ${\alpha}_1$-adrenoceptor mediated contraction by NE was greater than ${\alpha}_2$-adrenoceptor mediated contraction by NE in both arteries. NE-induced relaxation was decreased by rubbing of endothelium in both arteries. ${\alpha}_1-and\;{\alpha}_2$-adrenoceptor mediated contraction by NE were potentiated by rubbing of endothelium in both arteries. Pretreatment with methylene blue, an inhibitor of soluble guanylate cyclase, increased ${\alpha}_1-\;and\;{\alpha}_2$-adrenoceptor mediated contraction by NE in both arteries with endothelium. From the above results, we suggest that the effect of activation of $\alpha$-adrenoceptors by NE may be modulated by endothelium in the proximal and distal coronary arteries of pigs. This effect may be mediated via endothelium derived relaxing factor.

• Clinical and Experimental Pediatrics
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• 제50권6호
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• pp.556-564
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• 2007

목 적 : 본 연구에서는 현증 천식 환자의 BHR에는 기도 염증이 중요한 요인으로 작용하기 때문에 ${\beta}_2$-아드레날린 수용체 유전자와의 연관성이 나타나지 않지만, 청소년기 천식 관해 상태에서 지속되는 BHR에는 상대적으로 유전적인 영향이 강하기 때문에 ${\beta}_2$-아드레날린 수용체 유전자와의 연관성이 나타날 것이라는 가설을 세우고, 이를 검증해 보고자 하였다. 방 법 : 장기간 천식 관해 상태(최근 2년간 천식 증상이 없고 치료가 필요 없었던 경우)에서 BHR이 지속되는 청소년 202명(천식 관해군), 현증 천식 청소년 182명(현증 천식군), 정상군 200명을 대상으로, 메타콜린 기관지 유발검사와 피부단자시험을 시행하였으며 혈청 총 IgE를 측정하였다. ${\beta}_2$-아드레날린 수용체 유전자의 일배체형 분석을 위해 아미노산 16번과 27번을 포함하고 있는 ${\beta}_2$-아드레날린 수용체 유전자 부위를 polymerase chain reaction(PCR)으로 증폭한 뒤, 16번 유전형은 allele specific PCR, 27번 유전형은 PCR-restriction fragment length polymorphism (RFLP) 방법으로 분석하였다. 결 과 : Gly 동형접합자(homozygote)의 빈도는 정상군에서 14.5%, 현증 천식군에서 18.1%, 천식 관해군에서 24.2%로 증가하는 경향이 관찰되었으며(P=0.01), 현증 천식군과 정상군 사이에서는 차이가 없었지만 천식 관해군과 정상군 사이에서는 유의한 차이가 관찰되었다(P=0.01). Gly16-Gln27 일배체형 빈도는 정상군에서 36.5%, 현증 천식군에서 40.4%, 천식 관해군에서 44.6%로 증가하는 경향이 관찰되었으며(P=0.02), 현증 천식군과 정상군 사이에서는 차이가 없었지만 천식 관해군과 정상군 사이에서는 유의한 차이가 관찰되었다(P=0.02). 천식 관해군에서 Gly16-Gln27 일배체형의 수가 증가함에 따라 $PC_{20}$ 기하 평균값이 유의한 차이를 보임으로써(P=0.02) Gly16-Gln27 일배체형과 $PC_{20}$ 사이의 연관성이 관찰되었으나 현증 천식군에서는 이러한 연관성이 관찰되지 않았다. 결 론 : ${\beta}_2$-아드레날린 수용체 유전자가 BHR을 유발하는 유전자적 배경을 가지면서 천식 질병을 조절하는 역할을 하고 있음을 시사한다.

• 대한약리학회지
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• 제27권2호
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• pp.119-123
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• 1991

${\beta}-$수용체 효능약물 ((-)-NE), 길항약물 $((\pm)-propranolol,\;labetalol)$ 및 PDE 억제약물(imazodan, KR-30045, KR-30075 등)에 대한 ${\beta}-adrenoceptor$ binding 실험을 ${\beta}_1/{\beta}_2$ 비선택적 radioligand인 $(-)-[^3H]-DHA$를 사용하여 실시하였다. Saturation 실험에서 ${\beta}_1$ 및 ${\beta}_2$ 수용체를 모두 갖고 있는 rat 좌심실의 ${\beta}$ 수용체에 대한 $(-)-[^3H]-DHA$의 $K_d$ 값은 $1.5{\pm}0.43\;nM$, $B_{max}$는 $22.0{\pm}0.9\;fmol/mg$ protein이었다. $({\pm})propranolol$, labetalol 및 (-)NE는 단일상으로 $(-)-[^3H]-DHA$의 결합을 억제하였으며 Ki 값은 각각 $17.0{\pm}0.43\;nM$, $57.3{\pm}1.30\;nM$, $1.57{\pm}0.95\;{\mu}M$로 나타났다. 실험에 사용한 모든 PDE 억제약물들은 $(-)-[^3H]-DHA$ 결합을 $10^{-3}\;M$의 고농도에서도 10% 미만으로 억제했다. 실험결과, propraolol, labetalol 및 NE는 ${\beta}_1/{\beta}_2$ 수용체에 대해 비선택적인 약물로 나타났으며, imazodan 및 신합성 PDE 억제약물들은 rat 심근에 있는 ${\beta}-$수용체에 친화성이 거의 없음을 알 수 있었다.

• 대한약리학회지
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• 제31권1호
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• pp.39-51
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• 1995

갑상선 기능 항진증 심장에서의 ${\beta}-adrenoceptor$의 역할은 잘 알려져 있으나 ${\alpha}-adrenoceptor$에 대해서는 알려져 있지 않은 바, 저자 등은 갑상선 기능 항진증 기니픽 심장의 유두근에서 일반 미세 전극과 이온-선택적 미세 전극을 이용하여 세포내 $Na^+$과 $H^+$ 활성도에 대한 phenylephrine의 영향을 연구하였다. Phenylephrine ($10^{-5}$ 또는 $3{\times}10^{-5}M$)에 의한 ${\alpha}_1-adrenoceptor$ 자극은 다양한 활동전위의 변동, 수축기 막전위의 과분극 ($1.5{\pm}0.1mM$), 세포내 활성도 증가 ($0.4{\pm}0.15mM$), 현저한 수축력 증가 ($220{\pm}15%$) 그리고 세포내 pH의 증가 ($0.06{\pm}0.002\;unit$)를 일으켰고, 이와 같은 변동이 prazosin과 atenolol에 의해 차단되었다. 그래서 이들 효과가 ${\alpha}_1-adrenoceptor$를 경유함을 알 수 있었고, 역시, 세포내 $Na^+$ 활성도와 수축력 증가 효과가 $Na^{+}-H^{+}$ 교환기 억제제인 ethylisopropylamiloride로 차단됨으로 보아 ${\alpha}_1-adrenoceptor$ 자극은 $Na^{+}-H^{+}$ 교환기를 자극하여 세포내 $a^{i}_{Na}$와 pH를 증가시킴을 시사한다. 이는 ${\alpha}_1-adrenoceptor$ 자극에 의한 세포내 $Na^+$감소와 초기 수축력 감소 효과를 나타내는 정상 기니픽 심장과는 매우 다른 결과로 갑상선 기능 항진증 심장에서 ${\alpha}_1-adrenoceptor$는 매우 중요한 기능을 갖고 있음을 의미한다.

• 한국영양학회:학술대회논문집
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• 한국영양학회 2002년도 추계학술대회 및 총회
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• pp.86-86
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• 2002

• 대한수의학회지
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• 제44권2호
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• pp.207-215
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• 2004

It is well known that the hypothalamic-pituitary-adrenocortical (HPA) axis is under the negative feedback control of adrenal corticosteroids. Previous studies have suggested that glucocorticoids can regulate neuroendocrine cells in the paraventricular nucleus (PVN) by modulating catecholaminergic transmission, a major excitatory modulator of the HPA axis at the hypothalamic level. But, the effects of corticosteroids on the expression of adrenoceptor subtypes are not fully understood. In this work, we examined mRNA levels of six adrenoceptor subtypes (${\alpha}_{1A}$, ${\alpha}_{1B}$, ${\alpha}_{2A}$, ${\alpha}_{2B}$, ${\beta}_1$ and ${\beta}_2$) in the PVN of normal and adrenalectomized (ADX) rats. Total RNA ($2.5{\mu}g$) was extracted from PVN micropunches of brain slices ($500{\mu}m$) and analyzed by reverse transcription-polymerase chain reaction (RT-PCR). The levels of corticotropin-releasing hormone (CRH) mRNA were increased in the ADX rats relative to normal rats, indicating that the PVN had been liberated from the negative feedback of corticosteroids. Among the six adrenoceptor subtypes examined, mRNA levels for ${\alpha}_{1B}$- and ${\beta}_1$-adrenoceptors were increased, but the level for ${\beta}_2$-adrenoceptors was decreased in the ADX rats. The mRNA levels for the other three subtypes and for the general and neuronal specific housekeeping genes, glyceroaldehyde-3-phosphate dehydrogenase (GAPDH) and N-enolase, respectively, were not changed in the ADX rats. In conclusion, the results indicate that adrenal steroids selectively regulate the gene expression of adrenoceptor subtypes in the PVN.

• Archives of Pharmacal Research
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• 제28권12호
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• pp.1317-1323
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• 2005

In an attempt to examine the ability of benzisothiazole-based drugs to interact with $\beta$-adrenoceptors, a series of 1,2-benzisothiazole derivatives, which were substituted with various propanolamine or oxypropanolamine side chains in the 2 or 3 position, were synthesised and tested. The pharmacological activity of these compounds at the ,$\beta$-adrenoceptors was examined using isolated rat atria and small intestinal segments, which preferentially express the $\beta_{1}$- and $\beta_{3}$-adrenoceptor-mediated responses, respectively. None of these products showed any $\beta$-adrenoceptor agonistic activity. In contrast, the 2- and 3-substituted isopropyl, tert-butyl, benzyl, and piperonyl derivatives 2a-d and 3a-d elicited surmountable inhibition of the isoprena­line-induced chronotropic effects in the atria, suggesting competitive antagonism at the $\beta_{1}$­recognition site. The $pA_{2}$ values revealed tert-butyl 3b and the isopropyl substituted piperonyl derivatives 3a to be the most effective. Remarkably, many of the 2-substituted propanolamines were less active than the corresponding 3-substituted oxypropanolamines. With the exception of compound 3b, none of these drugs antagonised the muscle relaxant activity of isoprenaline in the intestine, suggesting no effect on the $\beta_{3}$-adrenoceptors. These results confirm the ability of the benzisothiazole ring to interact with the $\beta$-adrenoceptors, and demonstrate that 2-substitution with propanolamine or 3-substitution with oxypropanolamine groups yields compounds with preferential antagonistic activity at the cardiac $\beta_{1}$adrenoceptors. The degree of antagonism depends strongly on both the nature of the substituent and its position on the benzisothiazole ring.

• The Korean Journal of Physiology and Pharmacology
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• 제2권4호
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• pp.461-469
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• 1998

Tetrahydroisoquinoline (THI) alkaloids can be considered as cyclized derivatives of simple phenylethy-lamines, and many of them, especially with 6,7-disubstitution, demonstrate relatively high affinity for catecholamines. Two -OH groups at 6 and 7 positions are supposed to be essential to exert ?${\beta}-receptor$ activities. However, it is not clear whether -OH at 6,7 substitution of THIs also shows ?${\alpha}-adrenoceptor$ activities. In the present study, we investigated whether -OH or $-OCH_3$ substitutions of 6,7 position of THIs differently affect the ?1-adrenoceptor affinity. We synthesized two 1-naphthylmethyl THI alkaloids, $1-{\beta}-naphthylmethyl-6,7-dihydroxy-1,2,3,4-tetrahydroisoquinoline$ HBr (YS 51) and $1-{\beta}-naphthylmethyl-6, 7-dimethoxy-1,2,3,4-tetrahydroisoquinoline$ HCl (YS 55), and their pharmacological actions on ?${\alpha}_1-adrenoceptor$ were compared. YS 51 and YS 55, concentration-dependently relaxed endothelium-denuded rat thoracic aorta precontracted with phenylephrine (PE, 0.1 ${\mu}M$) in which $pEC_{50}$ were $5.89{\pm}0.21$ and $5.93{\pm}0.19$, respectively. Propranolol (30 nM) did not affect the relaxation-response curves to YS 51 and YS 55. Concentration-response curves to PE were shifted to right by the pretreatment with YS 51 or YS 55. The $pA_2$ values of YS 51 and YS 55 showed $6.05{\pm}0.24$ and $5.88{\pm}0.16$, respectively. Both probes relaxed KCl (65.4 mM)-contracted aorta and inhibited $CaCl_2-induced$ contraction of PE-stimulated endothelium- denuded rat thoracic aorta in $Ca^{2+}-free$ solutions. In isolated guinea pig papillary muscle, 1 and 10 ${\mu}M$ YS 51 increased contractile force about 4- and 8- fold over the control, respectively, along with the concentration-dependent increment of cytosolic $Ca^{2+}$ ions. While, 10 ${\mu}M$ YS 55 reduced the contractile force about 50 % over the control and lowered the cytosolic $Ca^{2+}$ level, in rat brain homogenates, YS 51 and YS 55 displaced $[^3H]prazosin$ binding competitively with Ki 0.15 and 0.12 ${\mu}M$, respectively. However, both probes were ineffective on $[^3H]nitrendipine$ binding. Therefore, it is concluded that two synthetic naphthylmethyl-THI alkaloids have considerable affinity to ?1-adrenenoceptors in rat aorta and brain.

• The Korean Journal of Physiology
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• 제14권1호
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• pp.25-30
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• 1980

It has been well known that beta-adrenoceptor is responsible for the renin release stimulatory and alpha-adrenoceptor may be inhibitory. It has been observed accidently that alpha-adrenergic agonist can inhibit renin release by just changing the medium temperature in Vitro experiment in this laboratory. A series of experiments were performed to clarify this interesting phenomena in Vitro experiment. Rat renal slices were incubated in PSS medium under gas phase at $37^{\circ}C$. The following results were observed. 1) Isoproterenol and norepinephrine resulted in renin release stimulatory in dose-dependent by the concentrations of $10^{-9}$ to $10^{-5}\;M/L$ at $37^{\circ}C$. 2) Norepinephrine resulted in renin release inhibitory in dose dependent by the concentrations of $10^{-7}$ to $10^{-5}\;M/L$, and almost no effect by isoproterenol $10^{-6}\;M/L$ at $20^{\circ}C$. 3) Phenoxybenzamine pretreatment at $37^{\circ}C$ accentuated isoproterenol stimulatory effect at $37^{\circ}C$. 4) Phenoxybenzamine pretreatment at $20^{\circ}C$ attenuated isoproterenol stimulatory effect at $37^{\circ}C$. These data suggest that the renal adrenoceptor(s) related to renin release maybe a single entity, and can be interconverted different forms in certain conditions.