However, the the effects of SK channels in colonic relaxation caused by estrogen is not well understood. Methods: The contractile activity of muscle strips from male Sprague-Dawley rats was estimated,

and colonic smooth muscle cells (SMCs) were grown in primary culture. Selleckchem Ferroptosis inhibitor Results: We found that 17β-estradiol (E2) inhibited colonic contractility, while the tissues responded to apamin, an SK channel inhibitor, with a transient increase in tension after carbachol-induced peak contractions. Preincubation with apamin partially prevented E2-induced relaxation. Double immunofluorescence staining showed that two SK channel subtypes, SK2 and SK3, are coexpressed with α-actin in colonic SMCs. The quantitative ratio of SK transcriptional expression in colonic SMCs was SK3 > SK2. E2 treatment significantly increased SK3 expression in colonic SMCs. The peak expression of SK3 was evident after 12 h and 24 h stimulation with 50 nM E2, which was considered the most effective concentration in vitro. SK3 expression was downregulated by ICI 182780, an estrogen receptor (ER) antagonist,

but was not influenced by bovine serum albumin–conjugated E2. Furthermore, the effect of selleck the ERα-selective agonist PPT on the expression of SK3 was almost the same as E2, while the ERβ-selective agonist DPN did not influence SK3 protein expression. Conclusion: Apamin-sensitive 上海皓元医药股份有限公司 SK3 channels may be involved in the E2-induced relaxing effect on rat colonic smooth muscle, and that this effect is mediated via the ERα. Key Word(s): 1. Estradiol; 2. SK channels; 3. Muscle contraction; 4. Colon; Presenting Author: CHAN-JUAN ZHONG Additional Authors: LI-PING DUAN

Corresponding Author: LI-PING DUAN Affiliations: Peking Uninversity Third Hospital Objective: Chronic stress can increase esophageal mucosa permeability and epithelial intercellular spaces (ICS), which is accompanied by increasing mucosal mast cells (MCs). It’s unknown of how MCs could involve in the process of stress-induced barrier function in gut. We try to explore the roles of MCs play in stress-induced esophageal barrier function. Methods: MCs intact wildtype Brown Norway rats (+/+) and MCs deficient gene-mutant rats (Ws/Ws) were subjected to chronic restraint stress (CRS) for 7 days. All rats were sacrificed at the 8th day and tissue/blood was harvested. Stress state was confirmed by weight loss and analysis of serum stress-related hormones. ICSs were measured by transmission electron microscope (TEM) and tight junction proteins (TJPs) were accessed to evaluate the epithelial barrier dysfuntion after stress. MCs were counted by alcian blue staining and their activation status was evaluated.