Department of Physiology, College of Medicine, Najran University, Saudi Arabia.
Can J Physiol Pharmacol. 2011 Nov;89(11):783-91. doi: 10.1139/y11-076. Epub 2011 Oct 18.
In this study, we tested the effect of urocortin 1 (Ucn1) on the contractility of gallbladder smooth muscle (GBSM) strips from guinea pigs and studied the involvement of corticotropin-releasing factor (CRF) receptors in this effect. The effect of Ucn1 on the isometric contractions of non-contracted and acetylcholine (Ach)-contracted GBSM, and the effects of CRF-R antagonists antalarmin and astressin 2B on the effect of Ucn1 were studied. In addition, the expression of receptors for CRF-R1 and CRF-R2 in guinea pig gallbladder were investigated using reverse transcription - polymerase chain reaction (RT-PCR). Ucn1 dose-dependently inhibited the contractility of GBSM. Moreover, Ucn1 decreased the resting tension, the mean contractile amplitude, and the contractile frequency in both non-contracted and Ach-contracted strips of GBSM. Furthermore, Ucn1 induced rightward shift of the Ach concentration-response curve of Ach in Ach-contracted strips. This inhibitory effect of Ucn1 on both non-contracted and Ach-contracted strips was inhibited by astressin 2B, but not by antalarmin. RT-PCR demonstrated that the CRF-R2, but not CRF-R1 receptor subtype is expressed in the muscularis muscle of guinea pig gallbladder. In conclusion, Ucn1 has an inhibitory effect on the contractility of GBSM of guinea pig, mediated through stimulating CRF-R2 receptors in GBSM. More studies are needed to clarify the intracellular signaling events involved in this effect.
在这项研究中，我们测试了 Urocortin 1（Ucn1）对豚鼠胆囊平滑肌（GBSM）条带收缩性的影响，并研究了促肾上腺皮质释放因子（CRF）受体在这种作用中的参与情况。我们研究了 Ucn1 对非收缩和乙酰胆碱（Ach）收缩的 GBSM 的等长收缩的影响，以及 CRF-R 拮抗剂安塔林和应激素 2B 对 Ucn1 作用的影响。此外，使用逆转录-聚合酶链反应（RT-PCR）研究了豚鼠胆囊中 CRF-R1 和 CRF-R2 受体的表达。Ucn1 剂量依赖性地抑制 GBSM 的收缩性。此外，Ucn1 降低了非收缩和 Ach 收缩的 GBSM 条带的静息张力、平均收缩幅度和收缩频率。此外，Ucn1 诱导 Ach 在 Ach 收缩条带中的浓度-反应曲线向右移位。Ucn1 对非收缩和 Ach 收缩条带的这种抑制作用被应激素 2B 抑制，但不被安塔林抑制。RT-PCR 表明，CRF-R2 而不是 CRF-R1 受体亚型在豚鼠胆囊的肌层中表达。总之，Ucn1 对豚鼠 GBSM 的收缩性具有抑制作用，通过刺激 GBSM 中的 CRF-R2 受体介导。需要进一步的研究来阐明涉及这种作用的细胞内信号事件。
