KATP channels are composed of sulphonylurea receptors (SURs) and potassium inward rectifiers (Kir6.x) that assemble to form a large octameric channel. This study was designed to examine the expression and role of sulphonylurea-binding regulatory subunits 1 [SUR1 (ABCC8)] and 2 [SUR2 (ABCC9)] of the KATP channels in the pregnant rat myometrium with particular regard to the contractility. RT-PCR and Western blot analysis were performed to detect the presence of SUR1 and SUR2. The SUR1 levels were markedly increased in the early stages of pregnancy. The highest level was detected on day 6 of pregnancy, while in the late stages the levels of SUR1 were significantly decreased. The SUR2 level remained unchanged throughout pregnancy. The SUR-non-selective diazoxide and the SUR2-selective pinacidil inhibited oxytocin-induced contractions. Glibenclatnide, a KATP channel blocker, antagonized both pinacidil and diazoxide-induced relaxations. It was established that SURs are responsible for pharmacological reactivity of K ATP channel openers. We conclude that, both SURs are involved in the KATP channel in the pregnant rat myometrium. It may further be concluded that "pinacidil-like" KATP channel openers may be of therapeutic relevance as tocolytic agents in the future.
|Translated title of the contribution||Ontogeny of sulphonylurea-binding regulatory submits of KATP channels in the pregnant rat myometrium|
|Number of pages||7|
|Journal||Acta pharmaceutica Hungarica|
|Publication status||Published - Oct 26 2011|
ASJC Scopus subject areas
- Pharmaceutical Science