Second Department of Cardiac Surgery, Medical University of Silesia, Katowice, Poland.
J Physiol Pharmacol. 2013 Jun;64(3):309-16.
It has beed showed that perivascular adipose tissue (PVAT) of human internal thoracic artery (ITA) releases adventitia/adipocyte-derived relaxing factor (ADRF). The precise mechanism of vasodilatatory effect of ADRF is still unknown. It was suggested that various potassium channels may be involved in the action of ADRF. The aim of this study was to assess the involvment of potassium channels in the vasorelaxing properties of ADRF in human internal thoracic artery. Human ITA rings were studied in vitro. First the ability of perivascular tissue of human ITA to release ADRF to the bath was checked. In subsequent experiments two fragments of skeletonised ITA were used to assess the involvement of various potassium channels in vasorelaxing action of PVAT. Segment of ITA, precontracted with serotonin (10(-5.5)M), was relaxed by adding PVAT to tissue bath, first without and then in the presence of appropriate potassium channel blocker. Second segment served as a control (no addition of PVAT). The magnitude of relaxation was measured and compared between preparations. This protocol was used to analyze the influence of iberiotoxin (100 nM), apamin (1 uM), 4-aminopyridine (1 mM, 5 mM), BaCl₂ (100 uM) and glibenclamide (10 uM). The addition of PVAT to precontracted skeletonized ITA caused significant vasorelaxation (54.6±8.03 mN versus 33.7±6.58 mN p=0.03). Similar effect was seen when 5 ml of aliquot from separate incubation of PVAT was added (36.3±5.45 mN versus 20.7±3.02 mN; p<0.001). PVAT dependent relaxation was blocked in the presence of Ca⁺² dependent potassium channel blocker iberiotoxin (47.4±16.67 mN versus 43.3±14.54 mN; p=0.36) and 4-aminopyridine (5 mM) (59.3±3.54 mN versus 51.6±4.77 mN; p=0.12). We conclude that perivascular adipose tissue of human ITA releases relaxing factor that seems to act with the involvement of Ca⁺² dependent potassium channels.
已经表明，人内部胸廓动脉（ITA）的血管周围脂肪组织（PVAT）释放出动脉外膜/脂肪细胞衍生的舒张因子（ADRF）。ADRF 的血管舒张作用的确切机制尚不清楚。有人认为，各种钾通道可能参与了 ADRF 的作用。本研究的目的是评估钾通道在人 ITA 的 ADRF 血管舒张特性中的作用。在体外研究了人 ITA 环。首先检查人 ITA 血管周围组织释放 ADRF 到浴液中的能力。在随后的实验中，使用两个去骨化的 ITA 片段来评估各种钾通道在 PVAT 的血管舒张作用中的参与。用 5-羟色胺（10(-5.5)M）预收缩的 ITA 段，通过将 PVAT 加入组织浴中使其松弛，首先在没有合适的钾通道阻滞剂的情况下，然后在存在的情况下。第二段作为对照（不添加 PVAT）。测量并比较两个制剂之间的松弛幅度。该方案用于分析 Iberiotoxin（100 nM）、Apamin（1 uM）、4-氨基吡啶（1 mM、5 mM）、BaCl₂（100 uM）和格列本脲（10 uM）的影响。向预收缩的去骨化 ITA 中加入 PVAT 可引起明显的血管舒张（54.6±8.03 mN 与 33.7±6.58 mN，p=0.03）。当加入来自单独的 PVAT 孵育的 5 ml 等分试样时，也观察到类似的效果（36.3±5.45 mN 与 20.7±3.02 mN，p<0.001）。在存在 Ca²⁺依赖性钾通道阻滞剂 Iberiotoxin（47.4±16.67 mN 与 43.3±14.54 mN，p=0.36）和 4-氨基吡啶（5 mM）的情况下，PVAT 依赖性舒张被阻断（59.3±3.54 mN 与 51.6±4.77 mN，p=0.12）。我们的结论是，人 ITA 的血管周围脂肪组织释放出一种似乎通过涉及 Ca²⁺依赖性钾通道的舒张因子。
