Estimation by an electrophysiological method of the expression of oxytocin receptor mRNA in human myometrium during pregnancy.
In order to evaluate the changes in uterine oxytocin receptor-specific mRNA during pregnancy, receptor expression in Xenopus oocytes are examined electrophysiologically following microinjection of mRNA from human uterus. In voltage-clamped oocytes injected with term myometrial mRNA, oxytocin elicited an inward current response. The amplitude of the oxytocin-induced current increased with increasing dose of oxytocin, but no current was elicited following stimulation with vasopressin. The oxytocin-induced current was completely eliminated as a result of pretreatment with a specific oxytocin antagonist. 21 of 27 oocytes injected with term myometrial mRNA showed a large amplitude (77.0 +/- 16.1 nA) reaction to oxytocin. In comparison, only 3 of 13 oocytes injected with early gestational myometrial mRNA exhibited a small amplitude (4.6 +/- 1.4 nA) reaction to oxytocin. No oxytocin response was observed in oocytes injected with non-pregnant myometrial mRNA. These results indicate that the striking increment in oxytocin sensitivity in term uterus depends on the increase in mRNA encoding oxytocin receptors.
Kimura
T
T
Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
Azuma
C
C
Saji
F
F
Takemura
M
M
Tokugawa
Y
Y
Miki
M
M
Ono
M
M
Mori
K
K
Tanizawa
O
O
D000818:Animals; D001681:Biological Assay; D004553:Electric Conductivity; D004594:Electrophysiology; D005260:Female; D015870:Gene Expression; D006801:Humans; D009215:Myometrium / Q000502:physiology*; D009865:Oocytes; D011247:Pregnancy / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics*; D011945:Receptors, Angiotensin / Q000235:genetics* / Q000502:physiology; D018045:Receptors, Oxytocin; D014982:Xenopus laevis
D012333:RNA, Messenger; D011945:Receptors, Angiotensin; D018045:Receptors, Oxytocin