Buck S H, Maurin Y, Burks T F, Yamamura H I
Life Sci. 1984 Jan 30;34(5):497-507. doi: 10.1016/0024-3205(84)90506-x.
The binding of 3H-substance P (3H-SP) to longitudinal muscle membranes of the guinea pig small intestine has been characterized. The binding of 3H-SP exhibited a high affinity (Kd = 0.5nM). It was saturable (Bmax = 2 fmoles/mg tissue), reversible, and temperature-dependent. Kinetic studies and competition of 3H-SP binding by unlabeled SP yielded Kd and Ki values, respectively, which were in good agreement with the Kd calculated from saturation studies. The binding of 3H-SP appeared to be dependent on the presence of divalent cations in the incubation buffer. It was displaced by SP and various analogs and fragments in the rank order of SP greater than SP-(2-11) = SP-(3-11) greater than Nle11- SP = physalaemin greater than SP-(4-11) greater than SP-(5-11) greater than eledoisin much greater than SP-(7-11). Our results indicate that 3H-SP binds in longitudinal muscle of the guinea pig small intestine to a biologically relevant receptor which in many respects resembles the SP receptor characterized in the brain and the salivary gland of the rat.
已对3H-物质P（3H-SP）与豚鼠小肠纵行肌膜的结合特性进行了研究。3H-SP的结合表现出高亲和力（解离常数Kd = 0.5nM）。它具有饱和性（最大结合量Bmax = 2飞摩尔/毫克组织）、可逆性且依赖温度。动力学研究以及未标记的SP对3H-SP结合的竞争分别得出了解离常数Kd和抑制常数Ki值，这些值与通过饱和研究计算得出的Kd值高度吻合。3H-SP的结合似乎依赖于孵育缓冲液中二价阳离子的存在。它可被SP及各种类似物和片段取代，取代顺序为：SP ＞ SP-(2 - 11) = SP-(3 - 11) ＞ Nle11 - SP = 蛙皮素 ＞ SP-(4 - 11) ＞ SP-(5 - 11) ＞ 伊氏缩胆囊素 ＞＞ SP-(7 - 11)。我们的结果表明，3H-SP在豚鼠小肠纵行肌中与一种生物学相关受体结合，该受体在许多方面类似于在大鼠脑和唾液腺中所鉴定的SP受体。
