Voltage-dependent potassium channels in cytokeratin-positive and cytokeratin-negative microvascular endothelial cells of the corpus luteum.
We have recently described cytokeratin-positive (CK(+)) and cytokeratin-negative (CK(-)) microvascular endothelial cells (MVECs) in the bovine corpus luteum. The two phenotypes show a different expression and release of adhesion molecules and cytokines. Since secretion of mediators is specifically regulated by the electrophysiological membrane parameters, this report will compare voltage-dependent potassium (K(+)) channels in the two cell types cultured under the same conditions. CK(+) and CK(-) MVECs derived from the microvascular bed of one organ differ in their K(+)-channel characteristics. In CK(-) MVECs, an inwardly rectifying K(+) current was discovered, showing the characteristics of the Kir2.1. CK(+) MVECs displayed a voltage-dependent K(+) current that activates rapidly on depolarization and inactivates very slowly, and is associated with a member of the Kv family. The mRNA for Kir2.1 was identified by RT-PCR in CK(-) and CK(+) MVECs, but there was no evidence of Kv1.4 mRNA in either of them. The function of Kir2.1 in CK(-) MVECs might be induced during cultivation, whereas CK(+) MVECs appear to be more resistant to environmental conditions and do not express an inward current.
Richter
Maik
M
Institute of Pharmacy, University of Leipzig, Germany.
Tscheudschilsuren
Gerelusul
G
Eschke
Dagmar
D
Aust
Gabriela
G
Spanel-Borowski
Katharina
K
Nieber
Karen
K
D000818:Animals; D002417:Cattle; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism*; D003338:Corpus Luteum / Q000098:blood supply*; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D007633:Keratins / Q000378:metabolism*; D051665:Kv1.4 Potassium Channel; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008833:Microcirculation / Q000187:drug effects / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D026902:Potassium Channel Blockers / Q000494:pharmacology; D015221:Potassium Channels / Q000235:genetics; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics; D024642:Potassium Channels, Voltage-Gated / Q000187:drug effects / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism
D051665:Kv1.4 Potassium Channel; D026902:Potassium Channel Blockers; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger; D007633:Keratins