Ionic currents in avian granulosa cells.
Transmembrane ionic currents have been recorded in single granulosa cells from the laying hen using the whole-cell patch-clamp technique. Under voltage-clamp conditions, depolarizing voltage steps evoked currents composed of a fast inactivating inward component and a delayed outward component. The former was activated at voltages more positive than -50 mV and was fully inactivated within 500 ms. It was blocked by D600 (methoxyverapamil) and by cobalt, suggesting that it is a calcium current. The latter displayed inward rectification and did not inactivate during long duration pulses. It was blocked by tetraethylammonium indicating that it is a potassium current. This is the first evidence of the existence of potassium and calcium transmembrane currents in granulosa cells.
Schwartz
J L
JL
Division of Biological Sciences, National Research Council of Canada, Ottawa, Ontario.
Mealing
G A
GA
Asem
E K
EK
Whitfield
J F
JF
Tsang
B K
BK
D000818:Animals; D001464:Barium / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002645:Chickens; D005260:Female; D005711:Gallopamil / Q000494:pharmacology; D006107:Granulosa Cells / Q000502:physiology*; D007473:Ion Channels / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D015221:Potassium Channels / Q000187:drug effects / Q000502:physiology; D019789:Tetraethylammonium; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D015220:Calcium Channels; D007473:Ion Channels; D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; D001464:Barium; D005711:Gallopamil; D019789:Tetraethylammonium; D002118:Calcium