 |
||||
|
||||
|
||||
|
||||
The Journal of Neuroscience, April 28, 2004, 24(17):4283-4292; doi:10.1523/JNEUROSCI.4938-03.2004
Behavioral/Systems/Cognitive
Neuroendocrine Control of Larval Ecdysis Behavior in Drosophila: Complex Regulation by Partially Redundant Neuropeptides
Anthony C. Clark, * Marta L. del Campo, * andJohn Ewer Cornell University, Entomology Department, Ithaca, New York 14853
To complete each molting cycle, insects display a stereotyped sequence of behaviors to shed the remains of the old cuticle. These behavioral routines, as well as other related physiological events, are critical for proper development and are under the control of several neuropeptides. Their correct deployment and concatenation depends on the complex actions and interactions among several peptide hormones: ecdysis triggering hormone (ETH), eclosion hormone (EH), and crustacean cardioactive peptide (CCAP). Numerous theories, some in conflict, have been proposed to define the functional hierarchies by which these regulatory factors operate. Here we use wild-type Drosophila and transgenic flies bearing targeted ablations of either EH or CCAP neurons, or ablations of both together, to reevaluate their roles. Consistent with findings in moths, our results suggest that EH and ETH affect the release of each other via a positive feedback, although ETH can also be released in the absence of EH. We show that EH and ETH both contribute to the air filling of the air ducts (trachea) of the next stage but that EH may play a primary role in this process. We present evidence that EH, whose actions have always been placed upstream of CCAP, may also regulate ecdysis independently of CCAP. Finally, we confirm that flies lacking EH neurons do not ecdyse prematurely when injected with ETH peptides. These findings are surprising and not easily explained by currently available hypotheses. We propose that important additional neuropeptides, and additional interactions between known regulators, contribute to the mechanisms underlying insect ecdysis behaviors.
Key words: eclosion hormone; ecdysis triggering hormone; CCAP; neurohormone; molt; neurosecretion; cGMP
Received Nov 4, 2003; revised March 3, 2004; accepted March 17, 2004.
This article has been cited by other articles:
D. B. Morton, J. A. Stewart, K. K. Langlais, R. A. Clemens-Grisham, and A. Vermehren
Synaptic transmission in neurons that express the Drosophila atypical soluble guanylyl cyclases, Gyc-89Da and Gyc-89Db, is necessary for the successful completion of larval and adult ecdysis
J. Exp. Biol., May 15, 2008; 211(10): 1645 - 1656.
[Abstract] [Full Text] [PDF]
T. Zhao, T. Gu, H. C. Rice, K. L. McAdams, K. M. Roark, K. Lawson, S. A. Gauthier, K. L. Reagan, and R. S. Hewes
A Drosophila Gain-of-Function Screen for Candidate Genes Involved in Steroid-Dependent Neuroendocrine Cell Remodeling
Genetics, February 1, 2008; 178(2): 883 - 901.
[Abstract] [Full Text] [PDF]
M. M. Davis, S. L. O'Keefe, D. A. Primrose, and R. B. Hodgetts
A neuropeptide hormone cascade controls the precise onset of post-eclosion cuticular tanning in Drosophila melanogaster
Development, December 15, 2007; 134(24): 4395 - 4404.
[Abstract] [Full Text] [PDF]
J. S. Chung, D. C. Wilcockson, N. Zmora, Y. Zohar, H. Dircksen, and S. G. Webster
Identification and developmental expression of mRNAs encoding crustacean cardioactive peptide (CCAP) in decapod crustaceans
J. Exp. Biol., October 1, 2006; 209(19): 3862 - 3872.
[Abstract] [Full Text] [PDF]
Y. Zilberstein, J. Ewer, and A. Ayali
Neuromodulation of the locust frontal ganglion during the moult: a novel role for insect ecdysis peptides
J. Exp. Biol., August 1, 2006; 209(15): 2911 - 2919.
[Abstract] [Full Text] [PDF]
|
|
|
|
 |
|