Ontogeny of sulfonylurea-binding regulatory subunits of KATP channels in the pregnant rat myometrium

Autor: George Falkay, Norbert Lovasz, Róbert Gáspár, Eszter Ducza
Rok vydání: 2011
Předmět:
Zdroj: REPRODUCTION. 142:175-181
ISSN: 1741-7899
1470-1626
DOI: 10.1530/rep-10-0492
Popis: ATP-sensitive potassium channels (KATPchannels) are composed of sulfonylurea 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 sulfonylurea-binding regulatory subunits 1 (SUR1 (ABCC8)) and 2 (SUR2 (ABCC9)) of the KATPchannels in the pregnant rat myometrium with particular regard to the contractility. RT-PCR and western blot analyses 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, whereas 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. Glibenclamide, a KATPchannel blocker, antagonized both pinacidil- and diazoxide-induced relaxations. It was established that SURs are responsible for pharmacological reactivity of KATPchannel openers. We conclude that both SURs are involved in the KATPchannel in the pregnant rat myometrium. It may further be concluded that ‘pinacidil-like’ KATPchannel openers may be of therapeutic relevance as tocolytic agents in the future.
Databáze: OpenAIRE