Postnatal changes in the substance P receptor on rabbit gastric smooth muscle.
Postnatal changes in the substance P receptor on rabbit gastric smooth muscle.
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兔胃平滑肌 P 物质受体的出生后变化。
DOI：
10.1152/ajpgi.1992.262.2.g291
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发表时间：
1992
期刊：
影响因子：
--
通讯作者：
McRoberts,JA
中科院分区：
文献类型：
--
作者：
Hyman,PE;Kimura,S;Tomomasa,T;Yuan,QX;SnapeJr,WJ;McRoberts,JA
我们利用放射性配体与组织匀浆的结合以及肌肉条的等长收缩来表征 1 岁（新生）和 7 日龄以及 4 周和 11 周龄（断奶）兔子胃平滑肌上的 P 物质 (SP) 受体。新生儿的斯卡查德分析是曲线的，表明存在多个结合位点。在新生儿中，高亲和力结合位点的解离常数（Kd）为2.2 +/- 0.3 nM，最大结合（Bmax）为0.57 +/- 0.06 pmol/mg DNA。高亲和力结合位点的数量随着年龄的增长而减少，到 11 周时消失。低亲和力位点的 Kd 比高亲和力位点的 Kd 大两个数量级以上。在 [3H]SP 的竞争性结合研究中，神经激肽的效力顺序是 SP 远大于神经激肽 A (NKA)，大于神经激肽 B (NKB)，表明高亲和力结合位点是 NK-1 受体。 [125I]NKA 还以高亲和力与新生儿组织匀浆结合。对于[125I]NKA，顺序是NKA大于SP大于NKB，表明NK-2受体也存在。在收缩研究中，阿托品和河豚毒素对速激肽刺激的收缩没有影响，表明速激肽仅对该组织产生肌源性影响。在新生兔中，SP 和 NKA 的效力和功效相似。新生兔中SP的半最大有效剂量（ED50）比断奶兔低近两个数量级； NKA 的效力没有改变。（摘要截断为 250 字）
We used radioligand binding to tissue homogenates and isometric contraction of muscle strips to characterize the substance P (SP) receptor on gastric smooth muscle from 1- (newborn) and 7-day-old and 4- and 11-wk-old (weanling) rabbits. Scatchard analysis for newborns was curvilinear, suggesting the presence of multiple binding sites. In newborns the dissociation constant (Kd) of high-affinity binding site was 2.2 +/- 0.3 nM, and the maximum binding (Bmax) was 0.57 +/- 0.06 pmol/mg DNA. The number of high-affinity binding sites decreased with age, disappearing by 11 wk. The Kd for the low-affinity site was more than two orders of magnitude greater than that of the high-affinity site. In competitive binding studies with [3H]SP, the order of potency for the neurokinins was SP much greater than neurokinin A (NKA) greater than neurokinin B (NKB), suggesting that the high-affinity binding sites were NK-1 receptors. [125I]NKA is also bound to newborn tissue homogenate with high affinity. With [125I]NKA the order was NKA greater than SP greater than NKB, suggesting that NK-2 receptors were also present. In contraction studies, atropine and tetrodotoxin had no effect on tachykinin-stimulated contraction, suggesting solely myogenic tachykinin effects on this tissue. In newborn rabbits, the potency and efficacy of SP and NKA were similar. The half-maximal effective dose (ED50) of SP was nearly two orders of magnitude less in newborn rabbits than in weanlings; the potency of NKA did not change.(ABSTRACT TRUNCATED AT 250 WORDS)