QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

First published online March 30, 2006
Journal of Experimental Biology 209, 1385-1394 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02114

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted 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 Worden, M. K. Articles by Camacho, J. A. Search for Related Content PubMed PubMed Citation Articles by Worden, M. K. Articles by Camacho, J. A. Social Bookmarking                         What's this?

Dual inhibition of the dactyl opener muscle in lobster

Mary Kate Worden^* and Joseph A. Camacho

Department of Neuroscience, University of Virginia, PO 801392, Charlottesville, VA 22908, USA

^* Author for correspondence (e-mail: mkw3k{at}virginia.edu)

Accepted 19 January 2006

The dactyl opener neuromuscular system of crayfish and lobster has long been a popular model system for studies of synaptic physiology and its modulation. Previous studies of its neural innervation in both species have reported that whereas the opener excitor axon (OE) and the specific opener inhibitor (OI) innervate the entire muscle, the common inhibitor (CI) is restricted to a small number of the most proximal muscle fibers and is the physiologically weaker of the two inhibitors. Here, we show in the lobster that, contrary to previous reports, CI innervates fibers along the entire extent of the dactyl opener muscle and thus shares the innervation targets of OE and OI. To characterize the physiological function of CI in the lobster dactyl opener system, we independently stimulated both OI and CI and compared their effects. The physiological impact of each inhibitor was similar: inhibitors elicit inhibitory junction potentials of similar sizes, both trigger muscle relaxations and both inhibit excitatory junction potentials and muscle contractions to a comparable extent. Thus, in the periphery, CI and OI appear to be equally powerful inhibitors with similar physiological roles, both in suppressing contractions triggered by the excitor OE and in directly relaxing muscle tension. In light of these observations, our understanding of the physiological roles of specific and common inhibitors in crustacean motor control requires reevaluation.

Key words: inhibition, dactyl opener, lobster, crustacean, CI, common inhibitor, Homarus americanus

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    Twitter    What's this?

This article has been cited by other articles:

				S. A. Qadri, J. Camacho, H. Wang, J. R. Taylor, M. Grosell, and M. K. Worden Temperature and acid-base balance in the American lobster Homarus americanus J. Exp. Biol., April 1, 2007; 210(7): 1245 - 1254. [Abstract] [Full Text] [PDF]

				J. L. Hamilton, C. R. Edwards, S. R. Holt, and M. K. Worden Temperature dependent modulation of lobster neuromuscular properties by serotonin J. Exp. Biol., March 15, 2007; 210(6): 1025 - 1035. [Abstract] [Full Text] [PDF]