Short periods of hypoxia activate a K+ current in central neurons.
The effect of hypoxia on ionic currents was studied in acutely dissociated substantia nigra neurons. Using an external solution containing 0 mM Na+ and 0.5 mM Co2+, we found that overall whole-cell outward currents increased by 15-20% during 3-4 min of hypoxia. This current was voltage sensitive and could be completely blocked by TEA- and Cs+, suggesting that this is a K+ current. In cell-attached patches with 150 mM K+ in the external solution, we recorded a large-conductance outward current which was not observed during baseline and was reversibly activated by hypoxia. These results therefore provide the first direct evidence for the activation of K+ channels during O2 deprivation in central neurons.
Jiang
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Department of Pediatrics, Yale University School of Medicine, New Haven, CT 06510.
Haddad
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GG
D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D002586:Cesium / Q000494:pharmacology; D004594:Electrophysiology; D002534:Hypoxia, Brain / Q000378:metabolism*; D066298:In Vitro Techniques; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010100:Oxygen / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013378:Substantia Nigra / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013757:Tetraethylammonium Compounds / Q000494:pharmacology
D015221:Potassium Channels; D013757:Tetraethylammonium Compounds; D002586:Cesium; D011188:Potassium; D010100:Oxygen