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) All Versions of this Article: 585/2/413    most recent jphysiol.2007.143032v1 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 Minami, A. Articles by Zucker, R. S. Search for Related Content PubMed PubMed Citation Articles by Minami, A. Articles by Zucker, R. S. Related Collections Neuroscience

¹ Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California, Berkeley, CA 94720, USA

Intense motor neuron activity induces a long-term facilitation (LTF) of synaptic transmission at crayfish neuromuscular junctions (NMJs) that is accompanied by an increase in the accumulation of presynaptic Ca²⁺ ions during a test train of action potentials. It is natural to assume that the increased Ca²⁺ influx during action potentials is directly responsible for the increased transmitter release in LTF, especially as the magnitudes of LTF and increased Ca²⁺ influx are positively correlated. However, our results indicate that the elevated Ca²⁺ entry occurs through the reverse mode operation of presynaptic Na⁺/Ca²⁺ exchangers that are activated by an LTF-inducing tetanus. Inhibition of Na⁺/Ca²⁺ exchange blocks this additional Ca²⁺ influx without affecting LTF, showing that LTF is not a consequence of the regulation of these transporters and is not directly related to the increase in [Ca²⁺]_i reached during a train of action potentials. Their correlation is probably due to both being induced independently by the strong [Ca²⁺]_i elevation accompanying LTF-inducing stimuli. Our results reveal a new form of regulation of neuronal Na⁺/Ca²⁺ exchange that does not directly alter the strength of synaptic transmission.

(Received 14 August 2007; accepted after revision 4 October 2007; first published online 4 October 2007)
Corresponding author R. S. Zucker: University of California, Molecular and Cell Biology Department, 111 Life Sciences Addition, Berkeley, CA 94720-3200, USA. Email: zucker{at}berkeley.edu

This article has been cited by other articles:

				M. E. Quinlan, C. O. Alberto, and M. Hirasawa Short-term potentiation of mEPSCs requires N-, P/Q- and L-type Ca2+ channels and mitochondria in the supraoptic nucleus J. Physiol., July 1, 2008; 586(13): 3147 - 3161. [Abstract] [Full Text] [PDF]

				L. B. Silverman-Gavrila and A. J. Smith Facilitating exchange: activity-dependent regulation of presynaptic Na+/Ca2+ exchange J. Physiol., April 15, 2008; 586(8): 2039 - 2040. [Full Text] [PDF]