title: Estimation by an electrophysiological method of the expression of oxytocin receptor mRNA in human myometrium during pregnancy.
abstract: 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.
authors.affiliation: Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kimura
authors.forename: C
authors.initials: C
authors.lastname: Azuma
authors.forename: F
authors.initials: F
authors.lastname: Saji
authors.forename: M
authors.initials: M
authors.lastname: Takemura
authors.forename: Y
authors.initials: Y
authors.lastname: Tokugawa
authors.forename: M
authors.initials: M
authors.lastname: Miki
authors.forename: M
authors.initials: M
authors.lastname: Ono
authors.forename: K
authors.initials: K
authors.lastname: Mori
authors.forename: O
authors.initials: O
authors.lastname: Tanizawa
mesh_terms: 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
chemical_list: D012333:RNA, Messenger; D011945:Receptors, Angiotensin; D018045:Receptors, Oxytocin