KCNQ genes encode a family of K+ channel a-subunits influencing cellular excitability in neurons and cardiomyocytes. Little is known about their role in smooth muscle. However, KCNQ1 is expressed in murine portal vein where it contributes to the resting membrane conductance (Ohya et al., 2003; Yeung & Greenwood 2005). The aim of this study was to i) examine gene expression, using RT-PCR, of KCNQ family members in non-pregnant rat and mouse myometrium and ii) determine the role of KCNQ channels in regulating spontaneous myometrial contractions using antagonists (chromanol 293B, linopirdine and XE991). Activity was measured as mean integral tension (MIT). MIT after drug application was expressed as a percentage of that during the preceding 15 min control period. XE991 had the greatest effect of all the antagonists; XE991 (10 mM) enhanced MIT to 186 ± 28% (n=10) compared to vehicle controls (94 ± 6 %, n=8-10, p=0.03). mRNA for KCNQ1 and KCNE1 was detected in mouse and rat myometrium (n=4-6). These results suggest a potential role for KCNQ channels in the regulation of spontaneous myometrial contractility.

This work is funded by Tommy's the baby charity (No. 1060508).