JN Ad Instruments
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
 QUICK SEARCH:   [advanced]


     


J Neurophysiol (November 28, 2007). doi:10.1152/jn.00718.2007
This Article
Right arrow Full Text (PDF)
Right arrow All Versions of this Article:
99/2/583    most recent
00718.2007v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Bui, T. V.
Right arrow Articles by Rose, P. K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Bui, T. V.
Right arrow Articles by Rose, P. K.
Submitted on June 27, 2007
Accepted on November 27, 2007

Relative location of inhibitory synapses and persistent inward currents determines the magnitude and mode of synaptic amplification in motoneurons

Tuan Vu Bui1*, Giovanbattista Grande2, and P. Ken Rose3

1 Department of Physiology, Queen's University, Kingston, Canada
2 Department of Neurosciences and Mental Health, Hospital for Sick Children, Toronto, Canada
3 Department of Physiology, Queens University, Kingston, Canada

* To whom correspondence should be addressed. E-mail: tuan.bui{at}dal.ca.

In some motoneurons, L-type calcium channels that partly mediate persistent inward currents (PICs) in motoneurons have been estimated to be arranged in 50 to 200 µm long discrete regions in the dendrites, centered 100 to 400 µm from the soma. As a consequence of this non-uniform distribution, the interaction between synaptic inputs to motoneurons and these channels may vary according to the distribution of the synapses. For instance, over 93% of synapses from Renshaw cells have been observed to be located 65 to 470 µm away from the cell body of motoneurons. Our goal was to assess whether Renshaw cell synapses are distributed in a position to more effectively control the activation of the L-type calcium channels. Using compartmental models of motoneurons with L-type calcium channels distributed in 100 µm long hot spots centered 100 to 400 µm away from the soma, we compared the inhibition generated by four distributions of inhibitory synapses: proximal, distal, uniform and one based on the location of Renshaw cell synapses on motoneurons. Regardless of whether the synapses were activated tonically or transiently, in the presence of L-type Ca2+ channels, inhibitory synapses distributed according to the Renshaw cell synapse distribution generate the largest inhibitory currents. The effectiveness of a particular distribution of inhibitory synapses in the presence of PICs depends on their ability to deactivate the channels underlying PICs, which is influenced by the superposition between synapses and channels, as well as the distance away from the somatic voltage-clamp.




This article has been cited by other articles:


Home page
J. Neurosci.Home page
K. P. Carlin, T. V. Bui, Y. Dai, and R. M. Brownstone
Staircase Currents in Motoneurons: Insight into the Spatial Arrangement of Calcium Channels in the Dendritic Tree
J. Neurosci., April 22, 2009; 29(16): 5343 - 5353.
[Abstract] [Full Text] [PDF]




HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH
Visit Other APS Journals Online
Copyright © 2007 by the The American Physiological Society.