Pharmacologic characterization of intrinsic mechanisms controlling tone and relaxation of porcine lower esophageal sphincter
Pharmacologic characterization of intrinsic mechanisms controlling tone and relaxation of porcine lower esophageal sphincter
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DOI：
10.1124/jpet.105.094482
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发表时间：
2006-03-01
影响因子：
3.5
通讯作者：
Clavé, P
中科院分区：
文献类型：
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作者：
Farré, R;Aulí, M;Clavé, P
用成年猪食管下括约肌（LES）环形条在器官浴中研究了介导LES松弛的神经递质。LES松弛硝普钠（1 nM - 3 μ M），血管活性肠肽（VIP）和垂体腺苷酸环化酶激活肽（PACAP; 1 nM - 1 μ M），ATP（10 μ M - 30 mM），和三羰基二氯钌二聚体（1 μ M - 1 mM）不受河豚毒素（1 μ M）或L-N-G-硝基精氨酸甲酯（L-NAME; 100 μ M）。降钙素基因相关肽（CGRP; 1 nM - 1 μ M）不影响LES张力。ATP松弛被1 μ M的apamin和P2 Y（1）拮抗剂MRS 2179（N-6-甲基2 ′-脱氧腺苷3 ′，5 ′-二磷酸; 10 μ M）阻断。Apamin抑制PACAP舒张。VIP和PACAP舒张被10 U/ml α-糜蛋白酶阻断。L-NAME（-62.52 +/- 13.13%）和1H[1，2，4]恶二唑-[4，3-alpha]喹喔啉-1-酮（ODQ; 10 μ M，-67.67 +/- 6.80%）类似地抑制电LES松弛，apamin阻断非氮能松弛。尼古丁舒张（100 μ M）可被L-NAME（-60.37 +/-10.8%）和ODQ（-41.90 +/-7.89%）抑制，apamin也阻断非氮能舒张。MRS 2179强烈抑制电刺激或尼古丁引起的非氮能和apamin敏感性LES舒张，α-糜蛋白酶和P2 X（1，2，3）受体拮抗剂NF 279轻微抑制（8，8 c-[羰基双（亚氨基-4，1-亚苯基羰基亚氨基-4，1-亚苯基羰基亚氨基）]双-1，3，5-萘三磺酸六亚硫酸盐; 10 μ M），并且不受锡原卟啉IX（100 μ M）的影响。内源性抑制性运动神经元刺激后，猪LES松弛由两条主要的神经肌肉通路介导：一氧化氮通过鸟苷酸环化酶信号传导和apamin不敏感机制介导，以及非氮能apamin敏感神经传递主要由ATP、ADP或作用于P2 Y（1）受体的相关嘌呤介导，以及嘌呤能P2 X（1，2，3）受体和PACAP的微小贡献。氮能和嘌呤能共递质表现出类似幅度的平行效应，没有重大的相互作用。我们的研究表明，在猪LES松弛中，CGRP没有作用，VIP和一氧化碳仅起次要作用。
The neurotransmitters mediating relaxation of lower esophageal sphincter (LES) were studied using circular LES strips from adult pigs in organ baths. LES relaxation by sodium nitroprusside (1 nM - 3 mu M), vasoactive intestinal peptide (VIP) and pituitary adenylate cyclase-activating peptide (PACAP; 1 nM - 1 mu M), ATP (10 mu M - 30 mM), and tricarbonyldichlororuthenum dimer (1 mu M - 1 mM) was unaffected by tetrodotoxin (1 mu M) or L-N-G-nitroarginine methyl ester (L-NAME; 100 mu M). Calcitonin gene-related peptide ( CGRP; 1 nM - 1 mu M) did not affect LES tone. ATP relaxation was blocked by 1 mu M apamin and the P2Y(1) antagonist MRS 2179 (N-6-methyl 2'-deoxyadenosine 3', 5'-bisphosphate; 10 mu M). Apamin inhibited PACAP relaxation. VIP and PACAP relaxation was blocked by 10 U/ml alpha-chymotrypsin. L-NAME (-62.52 +/- 13.13%) and 1H[1,2,4] oxadiazole-[4,3-alpha] quinoxalin-1-one (ODQ; 10 mu M, -67.67 +/- 6.80%) similarly inhibited electrical LES relaxation, and apamin blocked non-nitrergic relaxation. Nicotine relaxation (100 mu M) was inhibited by L-NAME (-60.37 +/- 10.8%) and ODQ (-41.90 +/- 7.89%), and apamin also blocked non-nitrergic relaxation. Non-nitrergic and apamin-sensitive LES relaxation by electrical stimulation or nicotine was strongly inhibited by MRS 2179, slightly inhibited by alpha-chymotrypsin and the P2X(1,2,3) receptor antagonist NF 279 (8,8 c-[carbonylbis(imino-4,1- phenylenecarbonylimino-4,1-phenylenecarbonylimino)] bis-1,3,5-naphthalenetrisulfonic acid hexasodium salt; 10 mu M), and unaffected by tin protoporphyrin IX (100 mu M). Porcine LES relaxation after stimulation of intrinsic inhibitory motor neurons is mediated by two main neuromuscular pathways: nitric oxide through guanylate cyclase signaling and apamin-insensitive mechanisms and by non-nitrergic apamin-sensitive neurotransmission mainly mediated by ATP, ADP, or a related purine acting on P2Y(1) receptors and a minor contribution of purinergic P2X(1,2,3) receptors and PACAP. Nitrergic and purinergic cotransmitters show parallel effects of similar magnitude without major interplay. Our study shows no role for CGRP and only a minor one for VIP and carbon monoxide in porcine LES relaxation.