Canver C C, Cooler S D, Saban R
Division of Cardiothoracic Surgery, University of Wisconsin School of Medicine, Madison 53792, USA.
J Surg Res. 1997 Sep;72(1):49-52. doi: 10.1006/jsre.1997.5155.
The interaction between primary afferent neurons containing neuropeptides and the vascular smooth muscle is incompletely understood. To explore the function of perivascular afferent neurons and to determine whether they produce local effects on vascular smooth muscle cells, we investigated the effects of acute capsaicin and substance P administration in vitro on human internal thoracic arteries (ITA). Vessels were obtained from patients undergoing coronary bypass or from multiorgan transplant donors. Fourteen ITA segments (5 mm wide) were suspended as rings between two stainless-steel stirrups in water-jacketed (37 degrees C) tissue baths under 2.5 to 3 g of basal tension. The tissue baths contained 10 mL physiological salt solution (PSS) of the following composition (mM): NaCl, 119; KCl, 4.7; NaH2PO4, 1.0; MgCl2, 0.5; CaCl2, 2.5; NaHCO3, 25; and glucose, 11; aerated continuously with 95% O2 and 5% CO2. Peptidase inhibitors (phosphoramidon and captopril) were added to PSS to decrease peptide degradation. Mechanical responses were measured isometrically and recorded on a polygraph via isotonic force transducers. Vessels were preconstricted with submaximal concentrations of norepinephrine. After the tension had stabilized, substance P or capsaicin was added cumulatively to the tissue bath. At the end of the experiments, the viability of ITA was verified by its responses to endothelial-dependent (acetylcholine) and endothelial-independent (sodium nitroprusside) vasodilators. In the endothelium-intact ITA segments, substance P produced relaxation of ITA smooth muscle while it induced slight contraction when the ITA was devoid of its endothelium (P = 0.0585). The addition of capsaicin to human ITA primarily produced contractile effects on the developed smooth muscle force. The capsaicin-induced contraction of the ITA smooth muscle was independent of endothelial cell integrity, although contraction was greater in the endothelium-intact ITA segments (P = 0.0165). The acute capsaicin exposure of human ITA revealed that primary afferent neurons containing neuropeptides innervate human ITAs. There is a real potential for perivascular afferent neurons and sensory peptides to influence the ITA smooth muscle function.
含有神经肽的初级传入神经元与血管平滑肌之间的相互作用尚未完全明了。为了探究血管周围传入神经元的功能，并确定它们是否对血管平滑肌细胞产生局部影响，我们在体外研究了急性给予辣椒素和P物质对人胸廓内动脉（ITA）的作用。血管取自接受冠状动脉搭桥手术的患者或多器官移植供体。将14个ITA节段（5毫米宽）作为环悬挂在水温为37摄氏度的带水套组织浴中的两个不锈钢马镫之间，基础张力为2.5至3克。组织浴中含有10毫升以下成分（毫摩尔）的生理盐溶液（PSS）：氯化钠119、氯化钾4.7、磷酸二氢钠1.0、氯化镁0.5、氯化钙2.5、碳酸氢钠25和葡萄糖11；持续用95%氧气和5%二氧化碳通气。向PSS中加入肽酶抑制剂（磷酰胺素和卡托普利）以减少肽的降解。通过等长测量机械反应，并通过等张力传感器在记录仪上记录。血管先用亚最大浓度的去甲肾上腺素预收缩。张力稳定后，将P物质或辣椒素累积加入组织浴中。实验结束时，通过ITA对内皮依赖性（乙酰胆碱）和内皮非依赖性（硝普钠）血管舒张剂的反应来验证ITA的活力。在内皮完整的ITA节段中，P物质使ITA平滑肌舒张，而当ITA没有内皮时，它会引起轻微收缩（P = 0.0585）。向人ITA中加入辣椒素主要对发达的平滑肌力量产生收缩作用。辣椒素诱导的ITA平滑肌收缩与内皮细胞完整性无关，尽管在内皮完整的ITA节段中收缩更大（P = 0.0165）。人ITA的急性辣椒素暴露表明，含有神经肽的初级传入神经元支配人ITA。血管周围传入神经元和感觉肽确实有可能影响ITA平滑肌功能。
