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: 92/3/1796    most recent 00138.2004v1 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 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 Viana Di Prisco, G. Articles by Alford, S. Search for Related Content PubMed PubMed Citation Articles by Viana Di Prisco, G. Articles by Alford, S.

Quantitative Investigation of Calcium Signals for Locomotor Pattern Generation in the Lamprey Spinal Cord

Department of Biological Sciences, University of Illinois , Chicago, Illinois 60607

Submitted 10 February 2004; accepted in final form 27 April 2004

Locomotor pattern generation requires the network coordination of spinal ventral horn neurons acting in concert with the oscillatory properties of individual neurons. In the spinal cord, N-methyl-D-aspartate (NMDA) activates neuronal oscillators that are believed to rely on Ca²⁺ entry to the cytosol through voltage-operated Ca²⁺ channels and synaptically activated NMDA receptors. Ca²⁺ signaling in lamprey ventral horn neurons thus plays a determinant role in the regulation of the intrinsic membrane properties and network synaptic interaction generating spinal locomotor neural pattern activity. We have characterized aspects of this signaling quantitatively for the first time. Resting Ca²⁺ concentrations were between 87 and 120 nM. Ca²⁺ concentration measured during fictive locomotion increased from soma to distal dendrites [from 208 ± 27 (SE) nM in the soma to 335 ± 41 nM in the proximal dendrites to 457 ± 68 nM in the distal dendrites]. We sought to determine the temporal and spatial properties of Ca²⁺ oscillations, imaged with Ca²⁺-sensitive dyes and correlated with fluctuations in membrane potential, during lamprey fictive locomotion. The Ca²⁺ signals recorded in the dendrites showed a great deal of spatial heterogeneity. Rapid changes in Ca²⁺-induced fluorescence coincided with action potentials, which initiated significant Ca²⁺ transients distributed throughout the neurons. Ca²⁺ entry to the cytosol coincided with the depolarizing phase of the locomotor rhythm. During fictive locomotion, larger Ca²⁺ oscillations were recorded in dendrites compared with somata in motoneurons and premotor interneurons. Ca²⁺ fluctuations were barely detected with dyes of lower affinity providing alternative empirical evidence that Ca²⁺ responses are limited to hundreds of nanomolars during fictive locomotion.

This article has been cited by other articles:

				T. Kohashi and Y. Oda Initiation of Mauthner- or Non-Mauthner-Mediated Fast Escape Evoked by Different Modes of Sensory Input J. Neurosci., October 15, 2008; 28(42): 10641 - 10653. [Abstract] [Full Text] [PDF]

				E. S. Hill and P. S. Katz Role of Membrane Potential in Calcium Signaling During Rhythmic Bursting in Tritonia Swim Interneurons J Neurophysiol, March 1, 2007; 97(3): 2204 - 2214. [Abstract] [Full Text] [PDF]

				A. Bonnot, G. Z. Mentis, J. Skoch, and M. J. O'Donovan Electroporation Loading of Calcium-Sensitive Dyes Into the CNS J Neurophysiol, March 1, 2005; 93(3): 1793 - 1808. [Abstract] [Full Text] [PDF]