TY - JOUR
T1 - Modulation of potassium current characteristics in human myometrial smooth muscle by 17 beta-estradiol and progesterone
AU - Knock, G A
AU - Tribe, R M
AU - Hassoni, A A
AU - Aaronson, P I
PY - 2001
Y1 - 2001
N2 - The K+ channel currents are important modulators of smooth muscle membrane potential and excitability. We assessed whether voltage-gated K+ currents from human myometrium are regulated by placental steroid hormones during pregnancy and labor. Pregnant human myometrial cells were isolated from samples obtained at cesarean section. Primary cultured cells were treated with 100 nM 17 beta -estradiol, 1 muM progesterone, or both hormones in combination for 24 h. Acute effects of the two hormones were also determined. The K+ currents were recorded using the standard whole-cell, patch-clamp technique. Primary cultures possessed both delayed rectifier (I,,) and A-like (I,) voltage-gated K+ currents. The 24-h 17 beta -estradiol treatment caused a hyperpolarizing shift in the steady-state inactivation of both I, and I,. Progesterone treatment also shifted the inactivation of I, and increased I,, amplitude by 60%-110%. Conversely, the combined treatment had no effect on these currents. Neither 17 beta -estradiol (0.1-1 muM) nor progesterone (1-5 muM) had any effect on the K+ current when applied acutely. These results show that 17 beta -estradiol should inhibit myometrial K+ channel activity, whereas progesterone is likely to have the opposite effect. These results are consistent with the respective procontractile and prequiescence roles for 17 beta -estradiol and progesterone in human uterus during pregnancy.
AB - The K+ channel currents are important modulators of smooth muscle membrane potential and excitability. We assessed whether voltage-gated K+ currents from human myometrium are regulated by placental steroid hormones during pregnancy and labor. Pregnant human myometrial cells were isolated from samples obtained at cesarean section. Primary cultured cells were treated with 100 nM 17 beta -estradiol, 1 muM progesterone, or both hormones in combination for 24 h. Acute effects of the two hormones were also determined. The K+ currents were recorded using the standard whole-cell, patch-clamp technique. Primary cultures possessed both delayed rectifier (I,,) and A-like (I,) voltage-gated K+ currents. The 24-h 17 beta -estradiol treatment caused a hyperpolarizing shift in the steady-state inactivation of both I, and I,. Progesterone treatment also shifted the inactivation of I, and increased I,, amplitude by 60%-110%. Conversely, the combined treatment had no effect on these currents. Neither 17 beta -estradiol (0.1-1 muM) nor progesterone (1-5 muM) had any effect on the K+ current when applied acutely. These results show that 17 beta -estradiol should inhibit myometrial K+ channel activity, whereas progesterone is likely to have the opposite effect. These results are consistent with the respective procontractile and prequiescence roles for 17 beta -estradiol and progesterone in human uterus during pregnancy.
U2 - 10.1095/biolreprod64.5.1526
DO - 10.1095/biolreprod64.5.1526
M3 - Article
VL - 64
SP - 1526
EP - 1534
JO - Biology of Reproduction
JF - Biology of Reproduction
IS - 5
ER -