title: In vitro differentiation of rabbit blastocyst cells.
abstract: Six- and seven-day post-coitus (p.c.) rabbit embryos have been cultured in an attempt to establish a trophectodermal cell line. Results indicate that cells with epithelial characteristics (i.e. positive staining for cytokeratin) will survive in culture until Passage 3. At that time a fibroblastlike cell becomes predominant. In addition, we have found that the presence of the inner cell mass is required for trophectodermal cells from 6-d p.c. embryos to attach to the collagen substrate. Culture of 7-d p.c. embryo explants often results in the development of cells that spontaneously contract. These cells stain positively for myosin, which indicates that they may be precardiac cells. Maximum diastolic potential was -59 +/- 1.2 mV and the threshold potential was -53 +/- 2.3 mV. Spontaneously contracting cells did not respond to atropine, acetylcholine, epinephrine, isoproterenol, or propranolol. Action potential seems to be a result of an inward calcium current, because the beating rate is decreased in a dose-related manner with the calcium channel blocker verapamil, whereas the voltage-sensitive sodium channel blocker tetrodotoxin was without effect.
authors.affiliation: Department of Physiology and Biophysics, University of Alabama, Birmingham 35294.
authors.forename: E B
authors.initials: EB
authors.lastname: Gargus
authors.forename: D H
authors.initials: DH
authors.lastname: Robinson
authors.forename: J K
authors.initials: JK
authors.lastname: Bubien
authors.forename: L B
authors.initials: LB
authors.lastname: Bugaisky
authors.forename: D J
authors.initials: DJ
authors.lastname: Benos
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology* / Q000473:pathology / Q000648:ultrastructure; D002454:Cell Differentiation; D002460:Cell Line; D002462:Cell Membrane / Q000502:physiology; D002478:Cells, Cultured; D004553:Electric Conductivity; D004622:Embryo, Mammalian / Q000166:cytology / Q000502:physiology; D005260:Female; D008297:Male; D008564:Membrane Potentials; D009132:Muscles / Q000166:cytology / Q000502:physiology; D011817:Rabbits