Action of hypoxia on different types of calcium channels in hippocampal neurons.
Whole-cell patch clamp and polarographic oxygen partial pressure (pO2) measurements were used to establish the sensitivity of high-voltage-activated (HVA) Ca2+ channel subtypes of CA1 hippocampal neurons of rats to hypoxic conditions. Decrease of pO2 to 15-30 mm Hg induced a potentiation of HVA Ca2+ currents by 94%. Using selective blockers of N- and L-types of calcium channels, we found that inhibition of L-type channels decreased the effect by 54%, whereas N-type blocker attenuated the effect by 30%. Taking into account the ratio of currents mediated by these channel subtypes in CA1 hippocampal neurons, we concluded that both types of HVA Ca2+ channels are sensitive to hypoxia, however, L-type was about 3.5 times more sensitive to oxygen reduction.
Lukyanetz
Elena A
EA
Bogomoletz Institute of Physiology, Bogomoletz str 4, Kiev 01024, Ukraine. elena@serv.biph.kiev.ua
Shkryl
Vyacheslav M
VM
Kravchuk
Olga V
OV
Kostyuk
Platon G
PG
D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism*; D006624:Hippocampus / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism*; D008564:Membrane Potentials; D009474:Neurons / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D051381:Rats; D017208:Rats, Wistar
D015220:Calcium Channels; D002118:Calcium