Effects of barium on stimulus-induced changes in [K+]o and field potentials in dentate gyrus and area CA1 of human epileptic hippocampus.
The effects of barium on stimulus-induced rises in [K+]o were studied in the dentate gyrus (DG) and area CA1 of human hippocampal slices. Rises in [K+]o elicited by repetitive stimulation of the hilus, stratum moleculare, alveus, or stratum radiatum were dependent on stimulus intensity and frequency. Barium augmented rises in [K+]o in the DG by about 120% but failed to do so in area CA1. In both DG and area CA1 barium had no effects on population spikes whereas stimulus-induced slow field potentials were reduced. Since barium interferes with K+ uptake and redistribution by blocking leak conductances and inwardly-rectifying currents in astrocytes, our findings suggest that glial cells in the sclerotic hippocampal area CA1 may contribute less to K+ regulation.
Institute of Physiology, Humboldt University Berlin, Germany.
S
S
Gabriel
A
A
Kivi
R
R
Kovacs
T N
TN
Lehmann
W R
WR
Lanksch
H J
HJ
Meencke
U
U
Heinemann
D000328:Adult; D001464:Barium / Q000494:pharmacology*; D018891:Dentate Gyrus / Q000187:drug effects / Q000378:metabolism*; D004594:Electrophysiology; D004827:Epilepsy / Q000378:metabolism*; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D011188:Potassium / Q000378:metabolism*
D001464:Barium; D011188:Potassium