Department of Physiology, Faculty of Medicine, Bursa Uludag University, 16059, Bursa, Turkey.
Protein Pept Lett. 2022;29(9):760-768. doi: 10.2174/0929866529666220729115541.
This study aimed to investigate the effects of irisin on rat tracheal smooth muscle contraction-relaxation responses and the roles of voltage-gated potassium (K) channels, ATP-sensitive potassium (KATP) channels, and large-conductance calcium-activated potassium (BK) channels in these effects.
Isometric contraction and relaxation responses of tracheal segments were measured using the tissue bath method. Submaximal contractions were induced by ACh (10 M) or KCl (60 mM), and then concentration-response curves of irisin (10 to 10 M) were obtained. For the temporal control, a double-distilled water group was formed. ACh and irisin were added to the baths after tracheal segments were incubated with 4-AP (K channel blocker), glibenclamide (K channel blocker), TEA, and iberiotoxin (BK channel blockers) to assess the role of K+ channels. In addition, a vehicle group was performed for the solvent dimethyl sulfoxide (DMSO).
Irisin exhibited the relaxant effects in tracheal segments precontracted with both ACh and KCl at concentrations of 10-10 M (p<0.05). Besides, incubations of 4-AP, glibenclamide, TEA, and iberiotoxin significantly inhibited the irisin-mediated relaxation (p<0.05), whereas DMSO incubation did not modulate irisin responses (p>0.05).
In conclusion, the first physiological results on the relaxant effects of irisin in rat trachea were obtained. Our findings demonstrated that irisin mediates concentration-dependent relaxation in rat tracheas. Moreover, the present study reported for the first time that irisin-induced bronchorelaxation is associated with the activity of the K+ channels.
本研究旨在探讨鸢尾素对大鼠气管平滑肌收缩-松弛反应的影响，以及电压门控钾（K）通道、ATP 敏感性钾（KATP）通道和大电导钙激活钾（BK）通道在这些作用中的作用。
采用组织浴法测量气管段的等长收缩和松弛反应。用 ACh（10 μM）或 KCl（60 mM）诱导次最大收缩，然后获得鸢尾素（10 到 10 μM）的浓度-反应曲线。为了进行时间控制，形成双蒸馏水组。在气管段用 4-AP（K 通道阻断剂）、格列本脲（K 通道阻断剂）、TEA 和 Iberiotoxin（BK 通道阻断剂）孵育后，向浴中加入 ACh 和鸢尾素，以评估 K+通道的作用。此外，还进行了溶剂二甲基亚砜（DMSO）的载体组实验。
鸢尾素在浓度为 10-10 μM 时对 ACh 和 KCl 预收缩的气管段表现出舒张作用（p<0.05）。此外，4-AP、格列本脲、TEA 和 Iberiotoxin 的孵育显著抑制了鸢尾素介导的舒张（p<0.05），而 DMSO 孵育并未调节鸢尾素的反应（p>0.05）。
总之，我们首次获得了鸢尾素在大鼠气管舒张作用的生理结果。我们的研究结果表明，鸢尾素介导大鼠气管的浓度依赖性舒张。此外，本研究首次报道鸢尾素诱导的支气管松弛与 K+通道的活性有关。
