title: Some electrical properties of human pregnant myometrium.
abstract: Membrane properties of the human pregnant myometrium were investigated with the conventional microelectrode and patch clamp methods. The majority of preparations produced spontaneous action potentials at a very low frequency, and action potentials were inhibited in sodium-deficient or calcium-free solutions. With the patch clamp technique with 120 mmol/L cesium-20 mmol/L tetraethylammonium in the pipette, the inward current was evoked by a depolarizing pulse above -40 mV from a holding potential of -60 mV and maximum amplitude was obtained at 0 mV. At a holding potential of -100 mV, the inward current could be evoked with less positive depolarizing pulses, and the membrane potential that evoked the maximum amplitude of inward current was shifted to a more negative potential. Single-channel current recording revealed that two types of calcium channels existed in human pregnant myometrium, with single-channel conductances of 12 and 29 pS. One of the calcium channels (12 pS) was inactivated at a holding potential of -60 mV.
authors.affiliation: Department of Obstetrics and Gynecology, Kyushu University, Fukuoka, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Inoue
authors.forename: K
authors.initials: K
authors.lastname: Nakao
authors.forename: K
authors.initials: K
authors.lastname: Okabe
authors.forename: H
authors.initials: H
authors.lastname: Izumi
authors.forename: S
authors.initials: S
authors.lastname: Kanda
authors.forename: K
authors.initials: K
authors.lastname: Kitamura
authors.forename: H
authors.initials: H
authors.lastname: Kuriyama
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D002118:Calcium / Q000493:pharmacokinetics; D015220:Calcium Channels / Q000502:physiology; D002462:Cell Membrane / Q000502:physiology / Q000648:ultrastructure; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008564:Membrane Potentials / Q000502:physiology; D008839:Microelectrodes; D009215:Myometrium / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D011247:Pregnancy / Q000502:physiology*
chemical_list: D015220:Calcium Channels; D002118:Calcium