High Ca(2+)/low Mg(2+) solution induces long-term depression in rat CA1 pyramidal neurons.
Inducing long-term depression (LTD), one type of synaptic plasticity, typically requires electrical stimulation. Using rat hippocampal slices, we show that increasing the Ca(2+) of the extracellular solution to 4 mM and decreasing the Mg(2+) to 0.1 mM induced LTD in the CA1 region in the absence of electrical stimulation. The ionically-induced-LTD occluded electrical stimulation-induced LTD and was not blocked by application of 50 microM D-2-amino-5-phosphonopentanoic acid (an N-methyl-D-aspartate receptor antagonist) or by 1 mM (RS)-alpha-methyl-4-carboxyphenylglycine (a metabotropic glutamate receptor antagonist) alone. However, LTD was not ionically induced in the presence of both inhibitors. Our findings suggest that altering tissue excitability by changing the ionic environment mimics electrical stimulation in the induction of LTD.
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Department of Molecular Neurobiology, Institute of Medical Science, University of Tokyo, Tokyo, Japan.
Kato
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Mikoshiba
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D015763:2-Amino-5-phosphonovalerate / Q000494:pharmacology; D000818:Animals; D001565:Benzoates / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005998:Glycine / Q000031:analogs & derivatives / Q000494:pharmacology; D006624:Hippocampus / Q000502:physiology*; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology*; D009473:Neuronal Plasticity / Q000187:drug effects*; D017966:Pyramidal Cells / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020123:Sirolimus / Q000494:pharmacology; D012996:Solutions; D016559:Tacrolimus / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology
D001565:Benzoates; D002121:Calcium Channel Blockers; D018691:Excitatory Amino Acid Antagonists; D012996:Solutions; C079694:alpha-methyl-4-carboxyphenylglycine; D015763:2-Amino-5-phosphonovalerate; D014700:Verapamil; D008274:Magnesium; D002118:Calcium; D005998:Glycine; D020123:Sirolimus; D016559:Tacrolimus