Inhibition of apamin-sensitive calcium dependent potassium channels facilitate the induction of long-term potentiation in the CA1 region of rat hippocampus in vitro.
Using field potential recording in the CA1-region of rat hippocampal slices we investigated the effect of apamin; a specific antagonist of small conductive calcium activated potassium channels on long-term potentiation (LTP). The experiments revealed that LTP of excitatory postsynaptic potentials induced by a single 100 Hz tetanization was intensified by extracellular application of apamin in a concentration range of 1-200 nM. No effects of apamin on LTP induced by triple 100 Hz tetanization were seen. We conclude that the positive modulation of LTP by apamin is effective in a nanomolar concentration range and dependent upon the employed tetanization. Because it has been shown that apamin-binding sites are affected by learning disorders including Alzheimer's disease, our finding suggests that changes in the sensitivity to apamin may result in memory disorders.
Behnisch
T
T
Leibniz Institute for Neurobiology, Project Group Neuropharmacology, Magdeburg, Germany. behnisch@ifn-magdeburg.de
Reymann
K G
KG
D000818:Animals; D001030:Apamin / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D046508:Culture Techniques; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D004566:Electrodes; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D017774:Long-Term Potentiation / Q000187:drug effects*; D008297:Male; D026902:Potassium Channel Blockers; D015221:Potassium Channels / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D013746:Tetany; D013997:Time Factors
D026902:Potassium Channel Blockers; D015221:Potassium Channels; D001030:Apamin; D002118:Calcium