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) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science 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 ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Liu, H. N. Articles by Komatsu, Y. Search for Related Content PubMed PubMed Citation Articles by Liu, H. N. Articles by Komatsu, Y.

Presynaptic Activity and Ca²⁺ Entry Are Required for the Maintenance of NMDA Receptor–Independent LTP at Visual Cortical Excitatory Synapses

Department of Visual Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya 464-8601, Japan

Submitted 25 June 2003; accepted in final form 29 March 2004

We have shown that some neural activity is required for the maintenance of long-term potentiation (LTP) at visual cortical inhibitory synapses. We tested whether this was also the case in N-methyl-D-aspartate (NMDA) receptor–independent LTP of excitatory connections in layer 2/3 cells of developing rat visual cortex. This LTP occurred after 2-Hz stimulation was applied for 15 min and always persisted for several hours while test stimulation was continued at 0.1 Hz. When test stimulation was stopped for 1 h after LTP induction, only one-third of the LTP instances disappeared, but most did disappear under a pharmacological suppression of spontaneous firing, indicating that LTP maintenance requires either evoked or spontaneous activities. LTP was totally abolished by a temporary blockade of action potentials with lidocaine or the removal of extracellular Ca²⁺ after LTP induction, but it persisted under a voltage clamp of postsynaptic cells or after a temporary blockade of postsynaptic activity with the glutamate receptor antagonist kynurenate, suggesting that LTP maintenance requires presynaptic, but not postsynaptic, firing and Ca²⁺ entry. More than one-half of the LTP instances were abolished after a pharmacological blockade of P-type Ca²⁺ channels, whereas it persisted after either L-type or Ni²⁺-sensitive Ca²⁺ channel blockades. These results show that the maintenance of NMDA receptor–independent excitatory LTP requires presynaptic firing and Ca²⁺ channel activation as inhibitory LTP, although the necessary level of firing and Ca²⁺ entry seems lower for the former than the latter and the Ca²⁺ channel types involved are only partly the same.

This article has been cited by other articles:

				B. D. Heifets, V. Chevaleyre, and P. E. Castillo Interneuron activity controls endocannabinoid-mediated presynaptic plasticity through calcineurin PNAS, July 22, 2008; 105(29): 10250 - 10255. [Abstract] [Full Text] [PDF]

				A. Sarihi, B. Jiang, A. Komaki, K. Sohya, Y. Yanagawa, and T. Tsumoto Metabotropic Glutamate Receptor Type 5-Dependent Long-Term Potentiation of Excitatory Synapses on Fast-Spiking GABAergic Neurons in Mouse Visual Cortex J. Neurosci., January 30, 2008; 28(5): 1224 - 1235. [Abstract] [Full Text] [PDF]

				A. Katoh, J. A. Jindal, and J. L. Raymond Motor Deficits in Homozygous and Heterozygous P/Q-Type Calcium Channel Mutants J Neurophysiol, February 1, 2007; 97(2): 1280 - 1287. [Abstract] [Full Text] [PDF]

				K. Yamada, T. Inagaki, R. Funahashi, Y. Yoshimura, and Y. Komatsu High-Frequency Stimulation Together with Adrenoceptor Activation Facilitates the Maintenance of Long-Term Potentiation at Visual Cortical Inhibitory Synapses Cereb Cortex, September 1, 2006; 16(9): 1239 - 1248. [Abstract] [Full Text] [PDF]

				B. D. Winters and T. J. Bussey Transient Inactivation of Perirhinal Cortex Disrupts Encoding, Retrieval, and Consolidation of Object Recognition Memory J. Neurosci., January 5, 2005; 25(1): 52 - 61. [Abstract] [Full Text] [PDF]