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

First published online October 5, 2006
Journal of Experimental Biology 209, 4000-4010 (2006)
Published by The Company of Biologists 2006
doi: 10.1242/jeb.02479

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 Bestman, J. E. Articles by Booker, R. Search for Related Content PubMed PubMed Citation Articles by Bestman, J. E. Articles by Booker, R. Social Bookmarking                         What's this?

The control of anterior foregut motility during a larval molt of the moth Manduca sexta involves the modulation of presynaptic activity

Jennifer E. Bestman^* and Ronald Booker

Department of Neurobiology and Behavior, Cornell University, Ithaca, NY 14853, USA

^* Author for correspondence (e-mail: bestman{at}cshl.org)

Accepted 1 August 2006

In the moth, Manduca sexta, anterior foregut motility is modulated during the larval–larval molts in order to control the timing of molting fluid (MF) ingestion. MF is the enzymatic mixture that destroys the outer cuticle so that it can be shed at the end of the molt. The onset of the larval–larval molt is characterized by a dramatic decline in the amplitude of the anterior foregut contractions so that MF is not prematurely ingested. As the end of the molt approaches, the robust contractions of the anterior foregut return and the MF is ingested, enabling the larva to free itself from its old cuticle. In the present study we examine possible mechanisms involved in modulating anterior foregut motility during a larval–larval molt. Our results reveal that the release of a blood-borne factor plays a role in the decline in anterior foregut peristaltic activity during the molt. This blood-borne factor reduces the efficacy of the presynaptic endings of the motorneurons, resulting in a reduction in the amplitude of the excitatory junctional potential (EJP) recorded from the anterior foregut musculature. We also present evidence that crustacean cardioactive peptide (CCAP) targets the motorneuron terminals and its actions are sufficient to trigger the dramatic increase in EJP amplitude and anterior foregut contractions. Finally, the surgical ablation of the subesophageal ganglion, which has been previously described to be a source of CCAP neurons and the CCAP projections to the anterior foregut region, blocks both the increase in anterior foregut motility and the ingestion of MF that normally occur at the end of a larval–larval molt.

Key words: molting, foregut, Manduca sexta, insect, ecdysis, CCAP, modulation

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

This article has been cited by other articles:

				A. Ayali The role of the arthropod stomatogastric nervous system in moulting behaviour and ecdysis J. Exp. Biol., February 15, 2009; 212(4): 453 - 459. [Abstract] [Full Text] [PDF]