Adrenergic activation of electrogenic K+ secretion in guinea pig distal colonic epithelium: desensitization via the Y2-neuropeptide receptor.
Adrenergic activation of electrogenic K+ secretion in guinea pig distal colonic epithelium: desensitization via the Y2-neuropeptide receptor.
复制标题
豚鼠远端结肠上皮中电动 K 分泌的肾上腺素激活：通过 Y2-神经肽受体脱敏。
DOI：
10.1152/ajpgi.00077.2009
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Halm,DanR
中科院分区：
文献类型：
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作者：
Zhang,Jin;Halm,SusanT;Halm,DanR
用多肽-YY(PYY)脱敏豚鼠远端结肠粘膜的肾上腺素能兴奋电刺激K+分泌。无论是肾上腺素(EPI)、前列腺素E_2(PGE_2)或氨基甲胆碱(CCH)刺激，在Ussing小室的粘膜浴液中加入PYY或神经肽Y(NPY)，均可抑制与电源性CL-−分泌相对应的短路电流。两种多肽均不能明显抑制协同分泌的大瞬时成分(PGE2+CCH)。持续Cl-−分泌PYY和NPY对∼的抑制作用分别为65%，IC50分别为4.1±0.9 nM和9.4±3.8 nM。这种抑制作用可被Y2-神经肽受体(Y2-NPR)拮抗剂BIIE0246消除，但不能被Y1-NPR拮抗剂BVD10消除。BIIE0246阻断Y2-NPR激活K+分泌的肾上腺素敏感性为(EC50)2.9±1.2 nM(EPI)和13.3±1.0 nM(去甲肾上腺素)，约为PYY时的4倍。RT-PCR检测到Y1-NPR和Y2-NPR的mRNA表达，免疫印迹检测到蛋白质的表达。Y1-npr和Y2-npr在̈Hn隐窝柱状上皮细胞和隐窝间表面上皮细胞的基底膜上有明显的免疫反应(Ir)。免疫组织化学方法检测隐窝附近的肾上腺素能神经的多巴胺-β-羟基酶，部分神经中也含有NPYir。BIIE0246的加入增加了分泌型激活的Isc，这与PYY或NPY的体外释放一致。因此，PYY和NPY能够抑制Cl-−的分泌能力，并使肾上腺素能K+分泌反应脱敏，从而对分泌激活提供直接的抑制平衡。
Adrenergic activation of electrogenic K+secretion in isolated mucosa from guinea pig distal colon was desensitized by peptide-YY (PYY). Addition of PYY or neuropeptide-Y (NPY) to the bathing solution of mucosae in Ussing chambers suppressed the short-circuit current (Isc) corresponding to electrogenic Cl−secretion, whether stimulated by epinephrine (epi), prostaglandin-E2(PGE2), or carbachol (CCh). Neither peptide markedly inhibited the large transient component of synergistic secretion (PGE2+ CCh). Sustained Cl−secretoryIscwas inhibited ∼65% by PYY or NPY, with IC50s of 4.1 ± 0.9 nM and 9.4 ± 3.8 nM, respectively. This inhibition was eliminated by BIIE0246, an antagonist of the Y2-neuropeptide receptor (Y2-NpR), but not by Y1-NpR antagonist BVD10. Adrenergic sensitivity for activation of K+secretion in the presence of Y2-NpR blockade by BIIE0246 was (EC50s) 2.9 ± 1.2 nM for epi and 13.3 ± 1.0 nM for norepinephrine, approximately fourfold greater than in the presence of PYY. Expression of mRNA for both Y1-NpR and Y2-NpR was indicated by RT-PCR of RNA from colonic mucosa, and protein expression was indicated by immunoblot. Immunoreactivity (ir) for Y1-NpR and Y2-NpR was distinct in basolateral membranes of columnar epithelial cells in the crypts of Lieberkühn as well as intercrypt surface epithelium. Adrenergic nerves in proximity with crypts were detected by ir for dopamine-β-hydroxylase, and a portion of these nerves also contained NPYir. BIIE0246 addition increased secretagog-activatedIsc, consistent with in vitro release of either PYY or NPY. Thus PYY and NPY were able to suppress Cl−secretory capacity and desensitize the adrenergic K+secretory response, providing a direct inhibitory counterbalance against secretory activation.