Effect of the zinc chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) on hippocampal mossy fiber calcium signals and on synaptic transmission

An important pool of chelatable zinc is present in the synaptic vesicles of mossy fiber terminals from hippocampal CA3 area, being zinc released following single or repetitive electrical stimulation. Previous studies have suggested different synaptic roles for released mossy fiber zinc, including th...

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Autores principales:	MATIAS,CARLOS M, MATOS,NUNO C, ARIF,MONA, DIONISIO,JOSE C, QUINTA-FERREIRA,M EMILIA
Lenguaje:	English
Publicado:	Sociedad de Biología de Chile 2006
Materias:	mossy fiber synapses long-term potentiation (LTP) Area CA3 presynaptic calcium Fura-2 Area CA1
Acceso en línea:	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000300013
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spelling	oai:scielo:S0716-976020060003000132014-01-24Effect of the zinc chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) on hippocampal mossy fiber calcium signals and on synaptic transmissionMATIAS,CARLOS MMATOS,NUNO CARIF,MONADIONISIO,JOSE CQUINTA-FERREIRA,M EMILIA mossy fiber synapses long-term potentiation (LTP) Area CA3 presynaptic calcium Fura-2 Area CA1 An important pool of chelatable zinc is present in the synaptic vesicles of mossy fiber terminals from hippocampal CA3 area, being zinc released following single or repetitive electrical stimulation. Previous studies have suggested different synaptic roles for released mossy fiber zinc, including the inhibition of presynaptic calcium and of postsynaptic N-methyl-D-aspartate (NMDA) and gamma amino-butiric acid (GABA A) receptors. The effect of endogenously released zinc on mossy fiber long-term potentiation (LTP) induction also is not yet established. We have investigated the effect of the permeant zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl) ethylenediamine (TPEN) on mossy fiber calcium and on synaptic transmission, before and during the application of LTP-inducing stimulation. We have found, using the calcium indicator Fura-2, that single and tetanically-evoked mossy fiber calcium signals are both enhanced in the presence of 20 μM TPEN, while the single field potentials are unaffected. As expected, no effect was observed on the single calcium signals or field potentials obtained at the CA3-CA1 synapses, from the CA1 area, which has a lower concentration of vesicular zinc. These results support the idea that at the hippocampal mossy fiber synapses, released zinc inhibits presynaptic calcium mechanisms. A higher concentration of TPEN (100 μM) significantly reduced mossy fiber synaptic transmission but did not prevent the induction of mossy fiber LTP, suggesting that zinc is not required for the formation of this form of LTP.info:eu-repo/semantics/openAccessSociedad de Biología de ChileBiological Research v.39 n.3 20062006-01-01text/htmlhttp://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000300013en10.4067/S0716-97602006000300013
institution	Scielo Chile
collection	Scielo Chile
language	English
topic	mossy fiber synapses long-term potentiation (LTP) Area CA3 presynaptic calcium Fura-2 Area CA1
spellingShingle	mossy fiber synapses long-term potentiation (LTP) Area CA3 presynaptic calcium Fura-2 Area CA1 MATIAS,CARLOS M MATOS,NUNO C ARIF,MONA DIONISIO,JOSE C QUINTA-FERREIRA,M EMILIA Effect of the zinc chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) on hippocampal mossy fiber calcium signals and on synaptic transmission
description	An important pool of chelatable zinc is present in the synaptic vesicles of mossy fiber terminals from hippocampal CA3 area, being zinc released following single or repetitive electrical stimulation. Previous studies have suggested different synaptic roles for released mossy fiber zinc, including the inhibition of presynaptic calcium and of postsynaptic N-methyl-D-aspartate (NMDA) and gamma amino-butiric acid (GABA A) receptors. The effect of endogenously released zinc on mossy fiber long-term potentiation (LTP) induction also is not yet established. We have investigated the effect of the permeant zinc chelator N,N,N',N'-tetrakis(2-pyridylmethyl) ethylenediamine (TPEN) on mossy fiber calcium and on synaptic transmission, before and during the application of LTP-inducing stimulation. We have found, using the calcium indicator Fura-2, that single and tetanically-evoked mossy fiber calcium signals are both enhanced in the presence of 20 μM TPEN, while the single field potentials are unaffected. As expected, no effect was observed on the single calcium signals or field potentials obtained at the CA3-CA1 synapses, from the CA1 area, which has a lower concentration of vesicular zinc. These results support the idea that at the hippocampal mossy fiber synapses, released zinc inhibits presynaptic calcium mechanisms. A higher concentration of TPEN (100 μM) significantly reduced mossy fiber synaptic transmission but did not prevent the induction of mossy fiber LTP, suggesting that zinc is not required for the formation of this form of LTP.
author	MATIAS,CARLOS M MATOS,NUNO C ARIF,MONA DIONISIO,JOSE C QUINTA-FERREIRA,M EMILIA
author_facet	MATIAS,CARLOS M MATOS,NUNO C ARIF,MONA DIONISIO,JOSE C QUINTA-FERREIRA,M EMILIA
author_sort	MATIAS,CARLOS M
title	Effect of the zinc chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) on hippocampal mossy fiber calcium signals and on synaptic transmission
title_short	Effect of the zinc chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) on hippocampal mossy fiber calcium signals and on synaptic transmission
title_full	Effect of the zinc chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) on hippocampal mossy fiber calcium signals and on synaptic transmission
title_fullStr	Effect of the zinc chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) on hippocampal mossy fiber calcium signals and on synaptic transmission
title_full_unstemmed	Effect of the zinc chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) on hippocampal mossy fiber calcium signals and on synaptic transmission
title_sort	effect of the zinc chelator n,n,n',n'-tetrakis (2-pyridylmethyl)ethylenediamine (tpen) on hippocampal mossy fiber calcium signals and on synaptic transmission
publisher	Sociedad de Biología de Chile
publishDate	2006
url	http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602006000300013
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Effect of the zinc chelator N,N,N',N'-tetrakis (2-pyridylmethyl)ethylenediamine (TPEN) on hippocampal mossy fiber calcium signals and on synaptic transmission

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