Document Detail


Nematocyst discharge in Hydra vulgaris: Differential responses of desmonemes and stenoteles to mechanical and chemical stimulation.
MedLine Citation:
PMID:  20601054     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
The effects of mechanical and chemical stimulation on desmoneme and stenotele discharge in Hydra vulgaris were quantified, in situ, in isolated tentacles and single tentacles with attached hypostomes. Cnidocils of desmonemes and stenoteles were stimulated 24h after tentacle ablation. Single impacts with maximum calculated forces of 3.7x10(-3) to 3.8x10(-2) Newtons were delivered by piezoelectrically-driven glass capillary probes. Video analysis revealed that desmonemes discharged at forces of 3.7x10(-3)N; stenoteles required forces of 1.9x10(-2)N. Desmonemes not directly stimulated discharged if another desmoneme was adequately stimulated; the effect was carried through to at least two adjacent battery cells. Tentacles responded to desmoneme stimulation, by bending at the stimulation site. These findings imply afferent excitatory pathways between nematocytes onto other nematocytes and myonemes. Locomotory nematocysts (atrichous isorhizas) discharged only in hypostome-attached tentacles contacting a substrate; desmonemes and stenoteles did not discharge during substrate attachment, implying differential neuronal inhibition. At low concentrations, bath-applied mucin, a prey-associated glycosylated protein, lowered desmoneme and stenotele firing thresholds, abolishing the force dose-dependency in stenoteles, and allowing them to discharge at previously below threshold forces. At higher concentrations, mucin inhibited discharge, suggesting an involvement in prey-induced feeding inhibition.
Authors:
A A Scappaticci; Fhyzeedon Kahn; G Kass-Simon
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Publication Detail:
Type:  Journal Article     Date:  2010-06-28
Journal Detail:
Title:  Comparative biochemistry and physiology. Part A, Molecular & integrative physiology     Volume:  157     ISSN:  1531-4332     ISO Abbreviation:  Comp. Biochem. Physiol., Part A Mol. Integr. Physiol.     Publication Date:  2010 Oct 
Date Detail:
Created Date:  2010-07-26     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9806096     Medline TA:  Comp Biochem Physiol A Mol Integr Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  184-91     Citation Subset:  IM    
Copyright Information:
2010 Elsevier Inc. All rights reserved.
Affiliation:
Department of Biologiocal Sciences, University of Rhode Island, Kingston, 02881, USA.
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