title: Potassium channel "inactivation" induced by soft-glass patch pipettes.
abstract: We have studied the potassium currents of rat pituitary pars intermedia cells kept in primary culture using whole-cell recording with patch pipettes. The potassium current recorded with hard-glass pipettes is mainly carried by voltage-dependent channels that show slow inactivation in the presence of 0.5 mM internal EGTA. Fast "inactivation" of the potassium current is seen with patch pipettes fabricated from soft glass (soda glass or potash lead glass), and is probably caused by block of the potassium channels by di- or multivalent cations released from the glass.
mesh_terms: D000818:Animals; D004533:Egtazic Acid / Q000494:pharmacology; D004553:Electric Conductivity; D005898:Glass; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D010902:Pituitary Gland / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D051381:Rats
chemical_list: D007473:Ion Channels; D004533:Egtazic Acid; D011188:Potassium