Secretin receptors mediating rat forestomach relaxation.
Secretin receptors mediating rat forestomach relaxation.
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介导大鼠前胃松弛的促胰液素受体。
DOI：
10.1152/ajpgi.1993.264.5.g863
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发表时间：
1993
期刊：
影响因子：
--
通讯作者：
S. Vigna
中科院分区：
文献类型：
--
作者：
T. Steiner;A. Mangel;D. C. Mcvey;S. Vigna
用125i标记的猪分泌素孵育大鼠胃冰冻切片，用放射自显影法定位分泌素结合位点。饱和结合仅在前胃近端外肌层（圆形和纵向平滑肌层）观察到。饱和结合用密度测定法定量。125i -猪分泌素与一类高亲和力结合位点结合，解离常数为0.6 nM。猪和大鼠分泌素对饱和型125i -猪分泌素结合的抑制作用基本相同，而对血管活性肠多肽、多肽组氨酸异亮氨酸和胰高血糖素的抑制作用则弱得多。体外实验中，100微米的甲萘醇刺激前胃肌张力持续增加，而猪分泌素使这种刺激的收缩松弛。我们得出结论，大鼠前胃平滑肌表达高亲和力特异性分泌素结合位点，介导松弛。这种推测的分泌素受体可能介导分泌素对胃运动的一些作用。
Frozen sections of the rat stomach were incubated with 125I-labeled porcine secretin, and then secretin binding sites were localized by autoradiography. Saturable binding was observed only in the muscularis externa (circular and longitudinal smooth muscle layers) of the proximal nonglandular forestomach. Saturable binding was quantitated by densitometry. 125I-porcine secretin bound to a single class of high-affinity binding sites with a dissociation constant of 0.6 nM. Porcine and rat secretins were nearly equipotent in inhibiting saturable 125I-porcine secretin binding, and vasoactive intestinal polypeptide, peptide histidine-isoleucine, and glucagon were much weaker. Carbachol (100 microM) stimulated a sustained increase in tension in forestomach muscle in vitro, and porcine secretin caused relaxation of this stimulated contraction. We conclude that rat forestomach smooth muscle expresses a high-affinity specific secretin binding site that mediates relaxation. This putative secretin receptor may mediate some of the actions of secretin on gastric motility.