HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Szinyei, C. Articles by Reymann, K. G. Search for Related Content PubMed PubMed Citation Articles by Szinyei, C. Articles by Reymann, K. G.

Inositol 1,3,4,5-tetrakisphosphate enhances long-term potentiation by regulating Ca²⁺ entry in rat hippocampus

Csaba Szinyei, Thomas Behnisch, Georg Reiser * and Klaus G. Reymann

The effect of inositol 1,3,4,5-tetrakisphosphate (InsP₄) on long-term potentiation (LTP) was investigated in the CA1 region of rat hippocampal slices. Intracellular application of InsP₄ and EPSP recordings were carried out using the whole-cell configuration.

Induction of LTP in the presence of InsP₄ (100 µM) resulted in a substantial enhancement of the LTP magnitude compared with control potentiation. Using an intrapipette perfusion system, it was established that application of InsP₄ was required during induction of potentiation for this enhancement to occur. An enhancement of LTP was not observed if a non-metabolizable inositol 1,4,5-trisphosphate (InsP₃) analogue (2,3-dideoxy-1,4,5-trisphosphate, 100 µM) was applied intracellularly.

Current-voltage relations of NMDA receptor-mediated EPSCs were not altered by InsP₄ application. The presence of InsP₄ was slightly effective in relieving a D-(-)-2-amino-5-phosphonopentanoic acid (D-APV)-induced block of LTP.

The peak current amplitude of voltage-gated calcium channels (VGCCs) was increased by InsP₄. -Conotoxin GVIA inhibited the InsP₄-induced LTP facilitation.

These data indicate that InsP₄ can modify the extracellular Ca²⁺ entry through upregulation of VGCCs, which may in turn contribute to the observed enhancement of LTP induced by InsP₄.

To investigate the possible involvement of intracellular Ca²⁺ release in the facilitatory effect of InsP₄ on LTP, different inhibitors of the endoplasmic reticulum-dependent Ca²⁺ release were applied (heparin, ryanodine, cyclopiazonic acid). The results suggest that InsP₄ activates postsynaptic InsP₃-dependent Ca²⁺ release which normally does not contribute to the calcium-induced calcium release-dependent LTP.

This article has been cited by other articles:

				S. M. Lloyd-Burton, J. C. H. Yu, R. F. Irvine, and M. J. Schell Regulation of Inositol 1,4,5-Trisphosphate 3-Kinases by Calcium and Localization in Cells J. Biol. Chem., March 30, 2007; 282(13): 9526 - 9535. [Abstract] [Full Text] [PDF]

				S. A. Walker, S. Kupzig, P. J. Lockyer, S. Bilu, D. Zharhary, and P. J. Cullen Analyzing the Role of the Putative Inositol 1,3,4,5-Tetrakisphosphate Receptor GAP1IP4BP in Intracellular Ca2+ Homeostasis J. Biol. Chem., December 6, 2002; 277(50): 48779 - 48785. [Abstract] [Full Text] [PDF]

				M. V. Baratta, T. Lamp, and M. K. Tallent Somatostatin Depresses Long-Term Potentiation and Ca2+ Signaling in Mouse Dentate Gyrus J Neurophysiol, December 1, 2002; 88(6): 3078 - 3086. [Abstract] [Full Text] [PDF]

				Y.-F. Lu and R. D. Hawkins Ryanodine Receptors Contribute to cGMP-Induced Late-Phase LTP and CREB Phosphorylation in the Hippocampus J Neurophysiol, September 1, 2002; 88(3): 1270 - 1278. [Abstract] [Full Text] [PDF]

				D. Communi, K. Gevaert, H. Demol, J. Vandekerckhove, and C. Erneux A Novel Receptor-mediated Regulation Mechanism of Type I Inositol Polyphosphate 5-Phosphatase by Calcium/Calmodulin-dependent Protein Kinase II Phosphorylation J. Biol. Chem., October 12, 2001; 276(42): 38738 - 38747. [Abstract] [Full Text] [PDF]

				M. J. Schell, C. Erneux, and R. F. Irvine Inositol 1,4,5-Trisphosphate 3-Kinase A Associates with F-actin and Dendritic Spines via Its N Terminus J. Biol. Chem., September 28, 2001; 276(40): 37537 - 37546. [Abstract] [Full Text] [PDF]