Home | My Profile | Contact Us
Research Trends Products  |   order gateway  |   author gateway  |   editor gateway  
Register | Forgot Password

Author Resources
 Author Gateway
 Article submission guidelines

Editor Resources
 Editor/Referee Gateway

 Regional Subscription Agents/Distributors
Trends in Comparative Biochemistry & Physiology   Volumes    Volume 1  Issue 2
Cellular signalling and glutathione-induced feeding response in hydra
Giorgio Venturini
Pages: 801 - 822
Number of pages: 22
Trends in Comparative Biochemistry & Physiology
Volume 1  Issue 2

Copyright © 1993 Research Trends. All rights reserved

Histochemical and biochemical data support the presence in hydra of classical neurotransmitters, such as dopamine, norepinephrine and serotonin, in addition to several neuropeptides. Pharmacological and physiological evidences obtained in hydra and in other coelenterates suggest for these substances a function in neurotransmission or modulation. For dopamine a role is suggested in the modulation of hydra glutathione-induced feeding response. The reduced glutathione (GSH) induces in hydra coordinated tentacles movements and mouth opening, presumably by interacting with a specific receptor, as demonstrated by the specific binding of labelled ligands to hydra membranes. Dopaminergic agonists inhibit the GSH action, as well as phosphodiesterase inhibitors. On the contrary dopaminergic blocking agents enhance and protract the feeding response. Both drugs specific for the D1 or D2 subclasses of dopaminergic receptors are active on feeding response and compete each other. cAMP levels are enhanced in hydra specimens treated with dopaminergic agents and a dopamine sensitive, G protein-coupled adenylate cyclase has been demonstrated in hydra. 6-hydroxydopamine treatment strongly enhances and protract GSH action and induces a significant reduction of dopamine levels. cAMP levels are also reduced. Tentacles` morphology is altered in 6-hydroxydopamine treated animals. These data are considered in favour of the presence of a dopaminergic receptor, incapable of discriminating between Dl selective and D2 selective agents, coupled, through a G protein, to adenylate cyclase. This dopaminergic mechanism could be responsible for a negative modulation of GSH-induced feeding reaction.
Buy this Article


Buy this article
Buy this volume
Subscribe to this title
Shopping Cart

Quick Links
Search Products
Browse in Alphabetical Order : Journals
Browse by Subject Classification : Journals

Ordering Information Ordering Information
Downloadable forms Downloadable Forms