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 Engel, D. Articles by Draguhn, A. Search for Related Content PubMed PubMed Citation Articles by Engel, D. Articles by Draguhn, A.

Laminar difference in GABA uptake and GAT-1 expression in rat CA1

Dominique Engel, Dietmar Schmitz, Tengis Gloveli, Christiane Frahm, Uwe Heinemann and Andreas Draguhn

1. The axonal plexus of most hippocampal interneurons is restricted to certain strata within the target region. This lamination suggests a possible functional heterogeneity of inhibitory synapses between different interneurons and CA1 pyramidal cells.

2. We therefore compared inhibitory postsynaptic potentials (IPSPs) and currents (IPSCs) in CA1 pyramidal cells, which were evoked from two stimulation sites (stratum oriens and stratum radiatum). Stimulation in stratum oriens yielded faster decaying IPSPs and IPSCs than stimulation in stratum radiatum.

3. IPSP and IPSC kinetics were regulated by GABA uptake in both layers as indicated by the prolongation of the signals under tiagabine, a GAT-1 (neuronal GABA plasma membrane transporter)-specific GABA-uptake blocker. However, the effect of tiagabine was significantly more pronounced following stimulation in stratum radiatum than in stratum oriens (prolongation of IPSC half-decay time by 167 vs. 115 %, respectively).

4. In situ hybridization with antisense mRNA for the GABA-synthesizing enzyme glutamate decarboxylase (GAD65/67) and the GABA transporter GAT-1 showed that the proportion of interneurons expressing GAT-1 was lower in stratum oriens than in stratum radiatum/lacunosum-moleculare.

5. From these functional and molecular data we conclude that the regulation of IPSP and IPSC kinetics in CA1 pyramidal cells by neuronal GABA uptake differs between layers. Our findings suggest that this laminar difference is caused by a lower expression of GAT-1 in interneurons in stratum oriens than in stratum radiatum/lacunosum-moleculare.

This article has been cited by other articles:

				J. Glykys and I. Mody The main source of ambient GABA responsible for tonic inhibition in the mouse hippocampus J. Physiol., August 1, 2007; 582(3): 1163 - 1178. [Abstract] [Full Text] [PDF]

				G. Casini, D. W. Rickman, and N. C. Brecha Expression of the {gamma}-Aminobutyric Acid (GABA) Plasma Membrane Transporter-1 in Monkey and Human Retina. Invest. Ophthalmol. Vis. Sci., April 1, 2006; 47(4): 1682 - 1690. [Abstract] [Full Text] [PDF]

				S. Keros and J. J. Hablitz Subtype-Specific GABA Transporter Antagonists Synergistically Modulate Phasic and Tonic GABAA Conductances in Rat Neocortex J Neurophysiol, September 1, 2005; 94(3): 2073 - 2085. [Abstract] [Full Text] [PDF]

				A. Bicho and C. Grewer Rapid Substrate-Induced Charge Movements of the GABA Transporter GAT1 Biophys. J., July 1, 2005; 89(1): 211 - 231. [Abstract] [Full Text] [PDF]

				D. Wang and M. W. Quick Trafficking of the Plasma Membrane {gamma}-Aminobutyric Acid Transporter GAT1: SIZE AND RATES OF AN ACUTELY RECYCLING POOL J. Biol. Chem., May 13, 2005; 280(19): 18703 - 18709. [Abstract] [Full Text] [PDF]

				A. Soragna, E. Bossi, S. Giovannardi, R. Pisani, and A. Peres Relations between substrate affinities and charge equilibration rates in the rat GABA cotransporter GAT1 J. Physiol., January 15, 2005; 562(2): 333 - 345. [Abstract] [Full Text] [PDF]

				K. Jensen, C.-S. Chiu, I. Sokolova, H. A. Lester, and I. Mody GABA Transporter-1 (GAT1)-Deficient Mice: Differential Tonic Activation of GABAA Versus GABAB Receptors in the Hippocampus J Neurophysiol, October 1, 2003; 90(4): 2690 - 2701. [Abstract] [Full Text] [PDF]

				L. S. Overstreet and G. L. Westbrook Synapse Density Regulates Independence at Unitary Inhibitory Synapses J. Neurosci., April 1, 2003; 23(7): 2618 - 2626. [Abstract] [Full Text] [PDF]

				G. C. Mathews and J. S. Diamond Neuronal Glutamate Uptake Contributes to GABA Synthesis and Inhibitory Synaptic Strength J. Neurosci., March 15, 2003; 23(6): 2040 - 2048. [Abstract] [Full Text] [PDF]

				C.-S. Chiu, K. Jensen, I. Sokolova, D. Wang, M. Li, P. Deshpande, N. Davidson, I. Mody, M. W. Quick, S. R. Quake, et al. Number, Density, and Surface/Cytoplasmic Distribution of GABA Transporters at Presynaptic Structures of Knock-In Mice Carrying GABA Transporter Subtype 1-Green Fluorescent Protein Fusions J. Neurosci., December 1, 2002; 22(23): 10251 - 10266. [Abstract] [Full Text] [PDF]