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: 97/4/2875    most recent 01313.2006v1 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 (2) Citing Articles via Google Scholar Google Scholar Articles by Blivis, D. Articles by Lev-Tov, A. Search for Related Content PubMed PubMed Citation Articles by Blivis, D. Articles by Lev-Tov, A.

Differential Effects of Opioids on Sacrocaudal Afferent Pathways and Central Pattern Generators in the Neonatal Rat Spinal Cord

¹Department of Anatomy and Cell Biology, The Hebrew University Medical School, Jerusalem, Israel; and ²Section of Developmental Neurobiology, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland

Submitted 15 December 2006; accepted in final form 6 February 2007

The effects of opioids on sacrocaudal afferent (SCA) pathways and the pattern-generating circuitry of the thoracolumbar and sacrocaudal segments of the spinal cord were studied in isolated spinal cord and brain stem-spinal cord preparations of the neonatal rat. The locomotor and tail moving rhythm produced by activation of nociceptive and nonnociceptive sacrocaudal afferents was completely blocked by specific application of the µ-opioid receptor agonist [D-Ala², N-Me-Phe⁴, Gly⁵-ol]-enkephalin acetate salt (DAMGO) to the sacrocaudal but not the thoracolumbar segments of the spinal cord. The rhythmic activity could be restored after addition of the opioid receptor antagonist naloxone to the experimental chamber. The opioid block of the SCA-induced rhythm is not due to impaired rhythmogenic capacity of the spinal cord because a robust rhythmic activity could be initiated in the thoracolumbar and sacrocaudal segments in the presence of DAMGO, either by stimulation of the ventromedial medulla or by bath application of N-methyl-D-aspartate/serotonin. We suggest that the opioid block of the SCA-induced rhythm involves suppression of synaptic transmission through sacrocaudal interneurons interposed between SCA and the pattern-generating circuitry. The expression of µ opioid receptors in several groups of dorsal, intermediate and ventral horn interneurons in the sacrocaudal segments of the cord, documented in this study, provides an anatomical basis for this suggestion.

This article has been cited by other articles:

				I. T. Gordon and P. J. Whelan Brainstem modulation of locomotion in the neonatal mouse spinal cord J. Physiol., May 15, 2008; 586(10): 2487 - 2497. [Abstract] [Full Text] [PDF]

				Y. Mor and A. Lev-Tov Analysis of Rhythmic Patterns Produced by Spinal Neural Networks J Neurophysiol, November 1, 2007; 98(5): 2807 - 2817. [Abstract] [Full Text] [PDF]