 |
||||
|
||||
|
||||
|
||||
Previous Article | Next Article
The Journal of Neuroscience, September 1, 1999, 19(17):7326-7333
Entire Course and Distinct Phases of Day-Lasting Depression of Miniature EPSC Amplitudes in Cultured Purkinje Neurons
Miho Murashima1 and Tomoo Hirano1, 2 1 Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan, and 2 Core Research for Evolutional Science and Technology, Japan Science and Technology Corporation, Kawaguchi, Saitama 332-0012, Japan
The cerebellar long-term depression (LTD) is the long-lasting reduction of transmission efficacy at the granule neuron-Purkinje neuron (G-P) synapses and is a candidate mechanism for the motor learning. Despite extensive studies on its induction and expression mechanisms, it has not been known how long the LTD lasts. The LTD is accompanied by the decrease in the postsynaptic responsiveness to glutamate, the transmitter at G-P synapses. Therefore, during the LTD, the amplitude of miniature EPSCs (mEPSCs) at G-P synapses should decrease. We studied the depression of mEPSC amplitudes (DME) as a possible contributing factor for the LTD and found that the conditioning treatment of cultured cerebellar neurons with 50 mM K+ and 100 µM glutamate, an analogous condition used to induce the LTD, induced the long-lasting DME. The mEPSC amplitudes recovered to the original level 48 hr after the 5 min conditioning treatment. Changing the duration of the conditioning revealed that the DME consisted of two distinct phases: the early phase lasting for a few hours and the late phase for >1 d. The latter was distinguished from the former by its requirement of prolonged conditioning treatment and syntheses of mRNA and protein for the induction. There were critical periods for mRNA and protein syntheses. The critical period for protein synthesis was much longer than that for mRNA synthesis. These results demonstrate that the DME lasts for 1-2 d and that it consists of two phases, whose induction and maintenance mechanisms are distinct.
Key words: synaptic plasticity; miniature EPSCs; culture; cerebellum; Purkinje neuron; long-term depression; late phase; critical period; mRNA synthesis; protein synthesis
Copyright © 1999 Society for Neuroscience 0270-6474/99/19177326-08$05.00/0
This article has been cited by other articles:
D. J. Linden
The expression of cerebellar LTD in culture is not associated with changes in AMPA-receptor kinetics, agonist affinity, or unitary conductance
PNAS, November 9, 2001; (2001) 241384598.
[Abstract] [Full Text] [PDF]
M. Ito
Cerebellar Long-Term Depression: Characterization, Signal Transduction, and Functional Roles
Physiol Rev, July 1, 2001; 81(3): 1143 - 1195.
[Abstract] [Full Text] [PDF]
N. Ho, J. A. Liauw, F. Blaeser, F. Wei, S. Hanissian, L. M. Muglia, D. F. Wozniak, A. Nardi, K. L. Arvin, D. M. Holtzman, et al.
Impaired Synaptic Plasticity and cAMP Response Element-Binding Protein Activation in Ca2+/Calmodulin-Dependent Protein Kinase Type IV/Gr-Deficient Mice
J. Neurosci., September 1, 2000; 20(17): 6459 - 6472.
[Abstract] [Full Text] [PDF]
M. Hirono, T. Sugiyama, Y. Kishimoto, I. Sakai, T. Miyazawa, M. Kishio, H. Inoue, K. Nakao, M. Ikeda, S. Kawahara, et al.
Phospholipase Cbeta 4 and Protein Kinase Calpha and/or Protein Kinase Cbeta I Are Involved in the Induction of Long Term Depression in Cerebellar Purkinje Cells
J. Biol. Chem., November 21, 2001; 276(48): 45236 - 45242.
[Abstract] [Full Text] [PDF]
D. J. Linden
The expression of cerebellar LTD in culture is not associated with changes in AMPA-receptor kinetics, agonist affinity, or unitary conductance
PNAS, November 20, 2001; 98(24): 14066 - 14071.
[Abstract] [Full Text] [PDF]
|
|
|
|
 |
|