Expression of stretch-activated potassium channels in human myometrium.

Using RT-PCR and a semiquantitative method to detect relative differences in mRNA expression, we examined uterine smooth muscle from both pregnant and non-pregnant women for the expression of members of weak inwardly rectifying 2-pore potassium channel family (TWIK), TREK and TRAAK. We show for the first time that TRAAK transcript is present in uterine smooth muscle, albeit at relatively low levels. The expression of TREK is far more robust. Trek-1 but not TREK-2 was expressed in both pregnant and non-pregnant myometrium. Comparison of TREK-1 expression in several hysterectomy samples relative to 18S ribosomal mRNA suggested that expression may be regulated or could vary from subject to subject since expression was not see in some women. A similar result was obtained in pregnant samples. When all samples expressing TREK-1 were compared, a significant increase in TREK-1 expression was seen in pregnant term tissues from women not in labor.