Identification of α1‐adrenoceptor subtypes in the rat vas deferens: binding and functional studies
Identification of α1‐adrenoceptor subtypes in the rat vas deferens: binding and functional studies
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大鼠输精管中α1-肾上腺素受体亚型的鉴定：结合和功能研究
DOI：
10.1111/j.1476-5381.1992.tb14509.x
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发表时间：
1992
影响因子：
7.3
通讯作者：
I. Muramatsu
中科院分区：
文献类型：
--
作者：
T. Ohmura;M. Oshita;S. Kigoshi;I. Muramatsu
1通过结合和功能实验对大鼠输精管前列腺和附睾部分的α1-肾上腺素受体亚型进行了表征。[2]在饱和实验中，[3 H]-哌唑嗪与大鼠输精管附睾部分的两个不同亲和位点结合（pKD分别为10.1 ± 0.13和9.01 ± 0.15，Bmax分别为507和1231 fmol mg−1蛋白）。在前列腺部分，[3 H]-哌唑嗪与单个亲和位点结合（pKD = 9.82 ± 0.04，Bmax = 924 fmol mg−1蛋白）。3在置换实验中，未标记的哌唑嗪双相置换了200 pm [3 H]-哌唑嗪与附睾部分的结合;所得的两个pKI值与饱和实验中获得的亲和常数一致。WB 4101（2-（2，6-二甲氧基-苯氧基乙基）-氨甲基-1，4-苯并二氧六环）和苯诺硫酸也区分了附睾部分的两个亲和力位点，三种拮抗剂的低亲和力位点群体约为40%。另一方面，前列腺部分主要显示出对哌唑嗪、WB 4101和苯诺沙坦的单一亲和力位点，尽管可以检测到小部分（小于10%）低亲和力位点的存在。HV 723（α-乙基-3，4，5-三甲氧基-α-（3-（（2-（2-甲氧基苯氧基）乙基）-氨基）-丙基）苯乙腈富马酸盐）置换了[3 H]-哌唑嗪，在两个半部分中以低亲和力单相结合。4用浓度高于1 μm的乙基可乐定（CEC）预处理可抑制700 pm [3 H]-哌唑嗪与前列腺部分的结合约50%。然而，附睾部分的抑制作用要小得多（在50 μm CEC下约为21%）。5在功能研究中，哌唑嗪、WB 4101、苯诺沙坦和HV 723竞争性抑制大鼠输精管对去甲肾上腺素的收缩反应，它们的亲和力相似但较低（pKB值为8.0 - 9.0）。在大鼠输精管的前列腺部分，去甲肾上腺素也产生收缩，但产生的最大收缩幅度约为附睾部分的四分之一。哌唑嗪和WB 4101也抑制前列腺部分的收缩反应，pKB值与附睾部分相似。1 μ mNifedipine可有效地减弱这两部分对去甲肾上腺素的收缩，但10 μ mCEC预处理对这两部分的收缩无影响。6在P2 x-嘌呤受体和连接前α2-肾上腺素受体被阻断的条件下，电透壁刺激在大鼠输精管的附睾部分产生快速发展的阶段性收缩和随后的强直性收缩。哌唑嗪（IC 50分别为25.7和25.9 nm）、WB 4101（IC 50 = 7.27和7.58 nm）、苯诺沙坦（IC 50 = 10.9和8.66 nm）和HV 723（IC 50 = 15.9和14.9 nm）以浓度依赖性方式抑制相位性和强直性收缩。硝苯地平选择性衰减电刺激引起的强直性收缩，和剩余的相位反应抑制上述拮抗剂具有类似的亲和力，在硝苯地平的情况下。CEC（10 μm）对肾上腺素能神经性收缩无明显影响。7目前的结果表明，大鼠输精管中存在两种不同的α1-肾上腺素受体亚型，分别对哌唑嗪、WB 4101和苯诺沙坦表现出高亲和力和低亲和力，根据最近的α1-肾上腺素受体亚型分类，推测对应于假定的α1A和α 1 L亚型。外源性和内源性去甲肾上腺素引起的收缩似乎主要通过α 1 L亚型介导。低亲和力位点（α 1 L亚型）的不均匀分布可以很好地解释大鼠输精管两部分功能反应性的差异。
1 The α1‐adrenoceptor subtypes of the prostatic and epididymal portion of rat vas deferens were characterized in binding and functional experiments. 2 In saturation experiments, [3H]‐prazosin bound to two distinct affinity sites in the epididymal portion of rat vas deferens (pKD = 10.1 ± 0.13 and 9.01 ± 0.15, Bmax = 507 and 1231 fmol mg−1 protein, respectively). In the prostatic portion [3H]‐prazosin bound to a single affinity site (pKD = 9.82 ± 0.04, Bmax = 924 fmol mg−1 protein). 3 In the displacement experiments, unlabelled prazosin displaced biphasically the binding of 200 pm [3H]‐prazosin to the epididymal portion; the resulting two pKI values were consistent with the affinity constants obtained in the saturation experiments. WB4101 (2‐(2,6‐dimethoxy‐phenoxyethyl)‐aminomethyl‐1,4‐benzodioxane) and benoxathian also discriminated the two affinity sites in the epididymal portion and the population of low affinity sites for the three antagonists was approximately 40%. On the other hand, the prostatic portion predominantly showed a single affinity site for prazosin, WB4101 and benoxathian, although the presence of a small proportion (less than 10%) of the low affinity site could be detected. HV723 (α‐ethyl‐3,4,5‐trimethoxy‐α‐(3‐((2‐(2‐methoxyphenoxy)ethyl)‐amino)‐propyl) benzeneacetonitrile fumarate) displaced the [3H]‐prazosin binding monophasically with a low affinity in both halves. 4 Pretreatment with chlorethylclonidine (CEC) at concentrations higher than 1 μm inhibited 700 pm [3H]‐prazosin binding to the prostatic portion by approximately 50%. However, the inhibition in the epididymal portion was much less (approximately 21% at 50 μm CEC). 5 In the functional study, the contractile response to noradrenaline was competitively inhibited by prazosin, WB4101, benoxathian and HV723 with similar and low affinities (pKB value ranging from 8.0 to 9.0) in the epididymal portion of rat vas deferens. In the prostatic portion of rat vas deferens, noradrenaline also produced a contraction, but the maximal amplitude of contraction developed was approximately one‐fourth of that in the epididymal portion. Prazosin and WB4101 also inhibited the contractile response of the prostatic portion with the pKB values similar to those obtained in the epididymal portion. The contractions to noradrenaline in both portions were potently attenuated by 1 μm nifedipine but were not affected by pretreatment with 10 μm CEC. 6 Under conditions where P2x‐purinoceptors and prejunctional α2‐adrenoceptors were blocked, electrical transmural stimulation produced a rapidly developing phasic contraction and a subsequent tonic contraction in the epididymal portion of rat vas deferens. The phasic and tonic contractions were inhibited in a concentration‐dependent manner by prazosin (IC50 = 25.7 and 25.9 nm, respectively), WB4101 (IC50 = 7.27 and 7.58 nm), benoxathian (IC50 = 10.9 and 8.66 nm) and HV723 (IC50 = 15.9 and 14.9 nm). Nifedipine selectively attenuated the tonic contraction induced by electrical stimulation, and the residual phasic response was inhibited by the antagonists mentioned above with similar affinities to those in the absence of nifedipine. CEC (10 μm) had little effect on the adrenergic neurogenic contractions. 7 The present results indicate the presence of two distinct α1‐adrenoceptor subtypes in the rat vas deferens, which show respectively high and low affinities for each of prazosin, WB4101 and benoxathian, and presumably correspond to putative α1A and α1L subtypes according to the recent α1‐adrenoceptor subclassifications. The contractions induced by exogenous and endogenous noradrenaline seem to be predominantly mediated through the α1L subtype. The heterogeneous distribution of the low affinity sites (α1L subtype) may well explain differences in functional responsiveness between the two portions of rat vas deferens.
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α 1-肾上腺素能受体亚型、磷酸肌醇和细胞 Ca2 来源。
影响因子：
21.1
作者：
Minneman,KP
通讯作者：
Minneman,KP
氯乙基可乐定揭示的 α1-肾上腺素能受体的异质性。
影响因子：
3.6
作者：
Han,C;Abel,PW;Minneman,KP
通讯作者：
Minneman,KP
影响因子：
3.6
作者：
A. Léan;A. Hancock;R. Lefkowitz
通讯作者：
A. Léan;A. Hancock;R. Lefkowitz
大鼠脑中α1-肾上腺素能受体亚型的表征：[3H]WB4104 和[3H]哌唑嗪结合的重新评估。
影响因子：
3.6
作者：
Morrow,AL;Creese,I
通讯作者：
Creese,I
α1A-肾上腺素受体 cDNA 的分子克隆和表达。
DOI：
--
发表时间：
1991
期刊：
The Journal of biological chemistry
影响因子：
--
作者：
Lomasney,JW;Cotecchia,S;Lorenz,W;Leung,WY;Schwinn,DA;Yang-Feng,TL;Brownstein,M;Lefkowitz,RJ;Caron,MG
通讯作者：
Caron,MG