Protection of potassium channel inhibitors against hypoxia/reoxygenation-induced death of cultured hippocampal neurons.
OBJECTIVE
To investigate the effects of potassium channel inhibitors on hypoxia/reoxygenation-induced death of cultured hippocampal neurons.


METHODS
Cultured 8 d in vitro, hippocampal neurons were exposed to hypoxia (in mixture of 95% N2 and 5% CO2) for 6 h, and then reoxygenated till the 72nd hour. Different potassium channel inhibitors were applied to the culture solution separately after reoxygenation. Neuron death was analyzed with cell counting and MTT assay.


RESULTS
Hypoxia/reoxygenation procedure induced a delayed death of cultured hippocampal neurons. Application of tetraethylammonium (TEA) offered concentration-dependent protection of the neurons against death. Selective high-conductance calcium-activated potassium channel (BK) inhibitor iberiotoxin (IbTX) showed significant neuron protection (P<0.001). However, A-type potassium channel inhibitor 4-aminopyridine presented no protection against neuron death (P>0.05).


CONCLUSIONS
Following hypoxia/reoxygenation, enhanced activity of potassium channel, especially BK channel, may induce neuron death.
Chen
Ming
M
Department of Physiology, First Military Medical University, Guangzhou 510515, China.
Sun
Hong-Yu
HY
Wang
Ying
Y
Gao
Tian-Ming
TM
D015761:4-Aminopyridine / Q000494:pharmacology*; D000818:Animals; D016923:Cell Death; D015687:Cell Hypoxia; D002478:Cells, Cultured; D006624:Hippocampus / Q000166:cytology; D051036:Large-Conductance Calcium-Activated Potassium Channels; D009474:Neurons / Q000166:cytology / Q000187:drug effects*; D010455:Peptides / Q000494:pharmacology*; D026902:Potassium Channel Blockers / Q000494:pharmacology*; D024681:Potassium Channels, Calcium-Activated / Q000037:antagonists & inhibitors*; D051381:Rats; D017207:Rats, Sprague-Dawley; D019789:Tetraethylammonium / Q000494:pharmacology*
D051036:Large-Conductance Calcium-Activated Potassium Channels; D010455:Peptides; D026902:Potassium Channel Blockers; D024681:Potassium Channels, Calcium-Activated; D019789:Tetraethylammonium; C064719:iberiotoxin; D015761:4-Aminopyridine