Identification and initial characterization of a putative neuromedin B-type receptor from rat urinary bladder membranes.
Identification and initial characterization of a putative neuromedin B-type receptor from rat urinary bladder membranes.
复制标题
大鼠膀胱膜中假定的神经调节素 B 型受体的鉴定和初步表征。
DOI：
10.1016/0014-2999(92)90588-u
复制
发表时间：
1992
影响因子：
5
通讯作者：
Coy,DH
中科院分区：
文献类型：
--
作者：
Bitar,KG;Coy,DH
用蛙皮素的生物活性类似物[Tyr 4，Leu 14]蛙皮素和50 000 × g总颗粒制剂表征大鼠膀胱膜上的受体结合位点。结合具有特异性、可逆性、饱和性、时间和浓度依赖性。解离曲线显示蛙皮素和神经介肽B在饱和后的第一个10分钟内同样取代了放射性配体。根据缔合速率常数k+1= 7.60 × 109 M − 1 min −1和解离速率常数k−1= 0.050 min−1，确定表观平衡解离常数Kd= 6.57 ± 1.09 pH。125 I-[Tyr 4，Leu 14]铃蟾肽与细胞膜特异性结合的线性Scatchard图显示，放射性配体以高亲和力（Kd= 6.38 ± 0.86 pM）与一类位点结合（Bmax= 2.3 fmol/mg蛋白质）。相同结合数据的希尔系数为1.05 ± 0.21，表明放射性配体与单一群体的非相互作用结合位点结合。蛙皮素和神经介肽B均以剂量依赖性方式取代放射性配体（IC 50 = 0.3 nM）。神经激肽A和神经激肽B的效力较低（IC 50分别为20和110 nM）。P物质或特异性蛙皮素受体拮抗剂[D-Phe 6]蛙皮素-（6-13）甲酯、[D-F5 Phe 6，D-Ala 11]蛙皮素-（6-11）甲酯、[D-Phe 6]蛙皮素-（6-13）丙酰胺、[D-Phe 6，Leu 13 psi（CH 2NH）Leu 14]蛙皮素或[D-Cpa 6，Phe 14（psi 13 -14）]蛙皮素-（6-14）的IC 50> 1μM。提出的结果表明，存在的神经介肽B受体网站上的大鼠膀胱膜，也可以被占领的一些其他肽，特别是蛙皮素，神经激肽A和神经激肽B。不能排除非特异性蛙皮素受体亚型的存在。
Receptor binding site(s) on the rat urinary bladder membranes were characterized using a biologically active analog of bombesin, [Tyr4, Leu14]bombesin, and a 50 000 ×gtotal particulate preparation. The binding was specific, reversible, saturable, time- and concentration-dependent. A dissociation curve showed that both bombesin and neuromedin B equally displaced the radioligand in the first 10 min after saturation. From the rate constant of association k+1= 7.60 × 109M−1min−1, and the rate constant of dissociation k−1= 0.050 min−1, the apparent equilibrium dissociation constant Kd= 6.57 ± 1.09 pH was determined. A linear Scatchard plot of the specific binding of125I-[Tyr4, Leu14]bombesin to the membranes revealed that the radioligand bound with high affinity, Kd= 6.38 ± 0.86 pM, to a single class of sites (Bmax= 2.3 fmol/mg protein). The Hill coefficient of the same binding data was 1.05 ± 0.21, indicating that the radioligand was binding to a single population of noninteracting bindings sites. Both bombesin and neuromedin B displaced the radioligand dose dependently (IC50= 0.3 nM). Neurokinin A and neurokinin B were less potent (IC50= 20 and 110 nM, respectively). Substance P, or the specific bombesin receptor antagonists [D-Phe6]bombesin-(6–13) methyl ester, [D-F5Phe6,D-Ala11]bombesin-(6–11) methyl ester, [D-Phe6]bombesin-(6–13) propylamide, [D-Phe6,Leu13psi(CH2NH)Leu14]bombesin or [D-Cpa6,Phe14(psi13–14)]bombesin-(6–14) had an IC50> 1μM. The results presented suggest the presence of neuromedin B receptor sites on the rat urinary bladder membranes that can be occupied also by some other peptides, notably bombesin, neurokinin A and neurokinin B. The presence of a non-specific bombesin receptor subtype cannot be excluded.