Ionic currents in avian granulosa cells |
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Authors: | J L Schwartz G A Mealing E K Asem J F Whitfield B K Tsang |
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Institution: | Division of Biological Sciences, National Research Council of Canada, Ottawa, Ontario. |
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Abstract: | 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. |
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