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

This Article 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 Kaila, K Articles by Deisz, R A Search for Related Content PubMed PubMed Citation Articles by Kaila, K Articles by Deisz, R A

Department of Zoology, University of Helsinki, Finland.

1. The ionic mechanism underlying the fast, GABAA receptor-mediated inhibitory postsynaptic potential (IPSPA) was examined in rat neocortical neurones using intracellular recording techniques. Synaptic responses were evoked by orthodromic stimulation applied to the subcortical white matter or to the pial surface. All experiments were carried out at a constant extracellular Cl- concentration. 2. The resting membrane potential was -76.2 +/- 1.0 mV (mean +/- S.E.M., n = 32) and in most cells IPSPA was depolarizing. The reversal potential of IPSPA (EIPSP-A) was -70.2 +/- 0.9 mV (n = 32) and that of a more slowly developing hyperpolarizing response (IPSPB) was -91.4 +/- 1.3 mV (n = 28). 3. An examination of the temporal relationships between excitatory postsynaptic potentials (EPSPs) and IPSPAs in different cells suggested that, despite partial overlap of these responses, EPSPs had little influence on the measured values of EIPSP-A. 4. Application of 20 mM trimethylamine (TriMA), a membrane-permeant weak base which is expected to produce a rise in pHi (and hence in intracellular HCO3-), induced a reversible positive shift in EIPSP-A of up to +9.0 mV (mean + 4.2 mV) at an extracellular pH (pHo) of 7.4. In some experiments, the shift in reversal potential was associated with a change in the polarity of IPSPA from hyperpolarizing to depolarizing. 5. Application of 20 mM lactate (a membrane-permeant weak acid which is expected to produce a fall in pHi and hence in intracellular HCO3-) at pHo 7.0 produced a hyperpolarizing shift in EIPS-A of up to -7.5 mV (mean -5.6 mV). In some experiments, exposure to lactate changed the polarity of IPSPA from depolarizing to hyperpolarizing. 6. Changes in pHo from 7.4 to 7.0 reduced the effect of TriMA and augmented that of lactate on EIPSP-A, as could be expected on the basis of the pHo-dependent change in the fraction of membrane permeable non-charged weak base or acid. 7. Under control conditions, a change in pHo from 7.4 to 7.0 produced a slight positive shift (< +2 mV) in EIPSP-A. In the presence of TriMA, a similar change in pHo gave rise to a negative shift (-1.8 to -2.7 mV). 8. The results obtained indicate that HCO3- ions contribute significantly to the IPSPA, thereby making EIPSP-A more positive than the Cl- equilibrium potential.(ABSTRACT TRUNCATED AT 400 WORDS)

This article has been cited by other articles:

				S. Khirug, J. Yamada, R. Afzalov, J. Voipio, L. Khiroug, and K. Kaila GABAergic Depolarization of the Axon Initial Segment in Cortical Principal Neurons Is Caused by the Na-K-2Cl Cotransporter NKCC1 J. Neurosci., April 30, 2008; 28(18): 4635 - 4639. [Abstract] [Full Text] [PDF]

				S. Jacobs, E. Ruusuvuori, S. T. Sipila, A. Haapanen, H. H. Damkier, I. Kurth, M. Hentschke, M. Schweizer, Y. Rudhard, L. M. Laatikainen, et al. Mice with targeted Slc4a10 gene disruption have small brain ventricles and show reduced neuronal excitability PNAS, January 8, 2008; 105(1): 311 - 316. [Abstract] [Full Text] [PDF]

				A. M. Kerr and M. Capogna Unitary IPSPs enhance hilar mossy cell gain in the rat hippocampus J. Physiol., January 15, 2007; 578(2): 451 - 470. [Abstract] [Full Text] [PDF]

				S. T. Sipila, S. Schuchmann, J. Voipio, J. Yamada, and K. Kaila The cation-chloride cotransporter NKCC1 promotes sharp waves in the neonatal rat hippocampus J. Physiol., June 15, 2006; 573(3): 765 - 773. [Abstract] [Full Text] [PDF]

				K. Morita, K. Tsumoto, and K. Aihara Bidirectional Modulation of Neuronal Responses by Depolarizing GABAergic Inputs Biophys. J., March 15, 2006; 90(6): 1925 - 1938. [Abstract] [Full Text] [PDF]

				M. Grob and D. Mouginot Heterogeneous chloride homeostasis and GABA responses in the median preoptic nucleus of the rat J. Physiol., December 15, 2005; 569(3): 885 - 901. [Abstract] [Full Text] [PDF]

				X. Jin, J. R. Huguenard, and D. A. Prince Impaired Cl- Extrusion in Layer V Pyramidal Neurons of Chronically Injured Epileptogenic Neocortex J Neurophysiol, April 1, 2005; 93(4): 2117 - 2126. [Abstract] [Full Text] [PDF]

				C. Rivera, J. Voipio, and K. Kaila Two developmental switches in GABAergic signalling: the K+-Cl- cotransporter KCC2 and carbonic anhydrase CAVII J. Physiol., January 1, 2005; 562(1): 27 - 36. [Abstract] [Full Text] [PDF]

				R. W. Putnam, J. A. Filosa, and N. A. Ritucci Cellular mechanisms involved in CO2 and acid signaling in chemosensitive neurons Am J Physiol Cell Physiol, December 1, 2004; 287(6): C1493 - C1526. [Abstract] [Full Text] [PDF]

				N. Kang, L. Jiang, W. He, J. Xu, M. Nedergaard, and J. Kang Presynaptic Inactivation of Action Potentials and Postsynaptic Inhibition of GABAA Currents Contribute to KA-Induced Disinhibition in CA1 Pyramidal Neurons J Neurophysiol, August 1, 2004; 92(2): 873 - 882. [Abstract] [Full Text] [PDF]

				M. D'Antuono, J. Louvel, R. Kohling, D. Mattia, A. Bernasconi, A. Olivier, B. Turak, A. Devaux, R. Pumain, and M. Avoli GABAA receptor-dependent synchronization leads to ictogenesis in the human dysplastic cortex Brain, July 1, 2004; 127(7): 1626 - 1640. [Abstract] [Full Text] [PDF]

				S. Sipila, K. Huttu, J. Voipio, and K. Kaila GABA Uptake via GABA Transporter-1 Modulates GABAergic Transmission in the Immature Hippocampus J. Neurosci., June 30, 2004; 24(26): 5877 - 5880. [Abstract] [Full Text] [PDF]

				J. Yamada, A. Okabe, H. Toyoda, W. Kilb, H. J. Luhmann, and A. Fukuda Cl- uptake promoting depolarizing GABA actions in immature rat neocortical neurones is mediated by NKCC1 J. Physiol., June 15, 2004; 557(3): 829 - 841. [Abstract] [Full Text] [PDF]

				A. Gulacsi, C. R. Lee, A. Sik, T. Viitanen, K. Kaila, J. M. Tepper, and T. F. Freund Cell Type-Specific Differences in Chloride-Regulatory Mechanisms and GABAA Receptor-Mediated Inhibition in Rat Substantia Nigra J. Neurosci., September 10, 2003; 23(23): 8237 - 8246. [Abstract] [Full Text] [PDF]

				K. Lamsa and T. Taira Use-Dependent Shift From Inhibitory to Excitatory GABAA Receptor Action in SP-O Interneurons in the Rat Hippocampal CA3 Area J Neurophysiol, September 1, 2003; 90(3): 1983 - 1995. [Abstract] [Full Text] [PDF]

				S. M. Leupen, S. A. Tobet, W. F. Crowley Jr., and K. Kaila Heterogeneous Expression of the Potassium-Chloride Cotransporter KCC2 in Gonadotropin-Releasing Hormone Neurons of the Adult Mouse Endocrinology, July 1, 2003; 144(7): 3031 - 3036. [Abstract] [Full Text] [PDF]

				M.-K. Sun and D. L. Alkon Impairment of Hippocampal CA1 Heterosynaptic Transformation and Spatial Memory by beta -Amyloid25-35 J Neurophysiol, May 1, 2002; 87(5): 2441 - 2449. [Abstract] [Full Text] [PDF]

				W. Kelsch, S. Hormuzdi, E. Straube, A. Lewen, H. Monyer, and U. Misgeld Insulin-Like Growth Factor 1 and a Cytosolic Tyrosine Kinase Activate Chloride Outward Transport during Maturation of Hippocampal Neurons J. Neurosci., November 1, 2001; 21(21): 8339 - 8347. [Abstract] [Full Text] [PDF]

				Y.-F. Wang, X.-B. Gao, and A. N. van den Pol Membrane Properties Underlying Patterns of GABA-Dependent Action Potentials in Developing Mouse Hypothalamic Neurons J Neurophysiol, September 1, 2001; 86(3): 1252 - 1265. [Abstract] [Full Text] [PDF]

				P. A. Gusev and D. L. Alkon Intracellular Correlates of Spatial Memory Acquisition in Hippocampal Slices: Long-Term Disinhibition of CA1 Pyramidal Cells J Neurophysiol, August 1, 2001; 86(2): 881 - 899. [Abstract] [Full Text] [PDF]

				M.-K. Sun, W.-Q. Zhao, T. J. Nelson, and D. L. Alkon Theta Rhythm of Hippocampal CA1 Neuron Activity: Gating by GABAergic Synaptic Depolarization J Neurophysiol, January 1, 2001; 85(1): 269 - 279. [Abstract] [Full Text] [PDF]

				X.-B. Gao and A. N. Van Den Pol GABA, Not Glutamate, a Primary Transmitter Driving Action Potentials in Developing Hypothalamic Neurons J Neurophysiol, January 1, 2001; 85(1): 425 - 434. [Abstract] [Full Text] [PDF]

				A. Kulik, H. Nishimaru, and K. Ballanyi Role of Bicarbonate and Chloride in GABA- and Glycine-Induced Depolarization and [Ca2+]i Rise in Fetal Rat Motoneurons In Situ J. Neurosci., November 1, 2000; 20(21): 7905 - 7913. [Abstract] [Full Text] [PDF]

				R. A. DeFazio, S. Keros, M. W. Quick, and J. J. Hablitz Potassium-Coupled Chloride Cotransport Controls Intracellular Chloride in Rat Neocortical Pyramidal Neurons J. Neurosci., November 1, 2000; 20(21): 8069 - 8076. [Abstract] [Full Text] [PDF]

				K. Lamsa, J. M. Palva, E. Ruusuvuori, K. Kaila, and T. Taira Synaptic GABAA Activation Inhibits AMPA-Kainate Receptor-Mediated Bursting in the Newborn (P0-P2) Rat Hippocampus J Neurophysiol, January 1, 2000; 83(1): 359 - 366. [Abstract] [Full Text] [PDF]

				S. Smirnov, P. Paalasmaa, M. Uusisaari, J. Voipio, and K. Kaila Pharmacological Isolation of the Synaptic and Nonsynaptic Components of the GABA-Mediated Biphasic Response in Rat CA1 Hippocampal Pyramidal Cells J. Neurosci., November 1, 1999; 19(21): 9252 - 9260. [Abstract] [Full Text] [PDF]

				K. L. Perkins Cl- Accumulation Does Not Account for the Depolarizing Phase of the Synaptic GABA Response in Hippocampal Pyramidal Cells J Neurophysiol, August 1, 1999; 82(2): 768 - 777. [Abstract] [Full Text] [PDF]

				L. Kiss and S. J. Korn Modulation of N-Type Ca2+ Channels by Intracellular pH in Chick Sensory Neurons J Neurophysiol, April 1, 1999; 81(4): 1839 - 1847. [Abstract] [Full Text] [PDF]

				Y. B. Liu, G.-L. Ye, X.-S. Liu, J. F. Pasternak, and B. L. Trommer GABAA Currents in Immature Dentate Gyrus Granule Cells J Neurophysiol, November 1, 1998; 80(5): 2255 - 2267. [Abstract] [Full Text] [PDF]

				K. Kaila, K. Lamsa, S. Smirnov, T. Taira, and J. Voipio Long-Lasting GABA-Mediated Depolarization Evoked by High-Frequency Stimulation in Pyramidal Neurons of Rat Hippocampal Slice Is Attributable to a Network-Driven, Bicarbonate-Dependent K+ Transient J. Neurosci., October 15, 1997; 17(20): 7662 - 7672. [Abstract] [Full Text] [PDF]

				M. Luckermann, S. Trapp, and K. Ballanyi GABA- and Glycine-Mediated Fall of Intracellular pH in Rat Medullary Neurons In Situ J Neurophysiol, April 1, 1997; 77(4): 1844 - 1852. [Abstract] [Full Text] [PDF]

				T. Taira, K. Lamsa, and K. Kaila Posttetanic Excitation Mediated by GABAA Receptors in Rat CA1 Pyramidal Neurons J Neurophysiol, April 1, 1997; 77(4): 2213 - 2218. [Abstract] [Full Text] [PDF]

				D. Ulrich and J. R. Huguenard Nucleus-Specific Chloride Homeostasis in Rat Thalamus J. Neurosci., April 1, 1997; 17(7): 2348 - 2354. [Abstract] [Full Text] [PDF]

				C. R. Rose and B. R. Ransom Mechanisms of H+ and Na+ Changes Induced by Glutamate, Kainate, and D-Aspartate in Rat Hippocampal Astrocytes J. Neurosci., September 1, 1996; 16(17): 5393 - 5404. [Abstract] [Full Text] [PDF]

				A. Agmon, G. Hollrigel, and D. K. O'Dowd Functional GABAergic Synaptic Connection in Neonatal Mouse Barrel Cortex J. Neurosci., August 1, 1996; 16(15): 4684 - 4695. [Abstract] [Full Text] [PDF]