| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1Oregon Hearing Research Center/Vollum Institute, Oregon Health and Science University, Portland, Oregon; and 2Institute of Experimental Medicine Academy of Sciences of the Czech Republic, 142 20 Prague 4, Czech Republic
Submitted 5 August 2004; accepted in final form 18 September 2004
Maturation of some brain stem and spinal inhibitory systems is characterized by a shift from GABAergic to glycinergic transmission. Little is known about how this transition is expressed in terms of individual axonal inputs and synaptic sites. We have explored this issue in the rat medial nucleus of the trapezoid body (MNTB). Synaptic responses at postnatal days 5–7 (P5–P7) were small, slow, and primarily mediated by GABAA receptors. By P8–P12, an additional, faster glycinergic component emerged. At these ages, GABAA, glycine, or both types of receptors mediated transmission, even at single synaptic sites. Thereafter, glycinergic development greatly accelerated. By P25, evoked inhibitory postsynaptic currents (IPSCs) were 10 times briefer and 100 times larger than those measured in the youngest group, suggesting a proliferation of synaptic inputs activating fast-kinetic receptors. Glycinergic miniature IPSCs (mIPSCs) increased markedly in size and decay rate with age. GABAergic mIPSCs also accelerated, but declined slightly in amplitude. Overall, the efficacy of GABAergic inputs showed little maturation between P5 and P20. Although gramicidin perforated-patch recordings revealed that GABA or glycine depolarized P5–P7 cells but hyperpolarized P14–P15 cells, the young depolarizing inputs were not suprathreshold. In addition, vesicle-release properties of inhibitory axons also matured: GABAergic responses in immature rats were highly asynchronous, while in older rats, precise, phasic glycinergic IPSCs could transmit even with 500-Hz stimuli. Thus development of inhibition is characterized by coordinated modifications to transmitter systems, vesicle release kinetics, Cl– gradients, receptor properties, and numbers of synaptic inputs. The apparent switch in GABA/glycine transmission was predominantly due to enhanced glycinergic function.
This article has been cited by other articles:
|
|
 |
|
  F. Rousseau, K. R. Aubrey, and S. Supplisson The Glycine Transporter GlyT2 Controls the Dynamics of Synaptic Vesicle Refilling in Inhibitory Spinal Cord Neurons J. Neurosci., September 24, 2008; 28(39): 9755 - 9768. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Schubert, D. Kerschensteiner, E. D. Eggers, T. Misgeld, M. Kerschensteiner, J. W. Lichtman, P. D. Lukasiewicz, and R. O. L. Wong Development of Presynaptic Inhibition Onto Retinal Bipolar Cell Axon Terminals Is Subclass-Specific J Neurophysiol, July 1, 2008; 100(1): 304 - 316. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Balakrishnan and L. O. Trussell Synaptic Inputs to Granule Cells of the Dorsal Cochlear Nucleus J Neurophysiol, January 1, 2008; 99(1): 208 - 219. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Ben-Ari, J.-L. Gaiarsa, R. Tyzio, and R. Khazipov GABA: A Pioneer Transmitter That Excites Immature Neurons and Generates Primitive Oscillations Physiol Rev, October 1, 2007; 87(4): 1215 - 1284. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L.-E. Trudeau and R. Gutierrez On Cotransmission & Neurotransmitter Phenotype Plasticity Mol. Interv., June 1, 2007; 7(3): 138 - 146. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. K Magnusson, C. Kapfer, B. Grothe, and U. Koch Maturation of glycinergic inhibition in the gerbil medial superior olive after hearing onset J. Physiol., October 15, 2005; 568(2): 497 - 512. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. P. Dugue, A. Dumoulin, A. Triller, and S. Dieudonne Target-Dependent Use of Coreleased Inhibitory Transmitters at Central Synapses J. Neurosci., July 13, 2005; 25(28): 6490 - 6498. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| Visit Other APS Journals Online |
