spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

First published online February 15, 2008
Journal of Experimental Biology 211, 661-670 (2008)
Published by The Company of Biologists 2008
doi: 10.1242/jeb.011478
This Article
Right arrow Figures Only
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Maurer, G.
Right arrow Articles by Grieshaber, M. K.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Maurer, G.
Right arrow Articles by Grieshaber, M. K.
Social Bookmarking
Add to CiteULike   Add to Complore   Add to Connotea   Add to Del.icio.us   Add to Digg   Add to Reddit   Add to Technorati   Add to Twitter  
What's this?

Modulatory effects of adenosine and adenine nucleotides on different heart preparations of the American lobster, Homarus americanus

Gereon Maurer1,*, Jerrel L. Wilkens2 and Manfred K. Grieshaber1

1 Institut für Zoophysiologie, Heinrich-Heine-Universität, Universitätsstraße 1, 40225 Düsseldorf, Germany
2 Department of Biological Science, University of Calgary, Calgary, Alberta T2N 1N4, Canada

* Author for correspondence (e-mail: maurerg{at}uni-duesseldorf.de)

Accepted 5 December 2007

As shown previously, adenosine and the adenine nucleotides cause a rapid increase in heart rate (fH) and haemolymph velocity (vHL) when infused into intact American lobster (Homarus americanus). Here we compare the effects of adenosine and adenine nucleotides on different heart preparations in order to gain insight into their sites of action. In the semi-isolated (in situ) heart preparation where the heart is uncoupled from neural and hormonal influence AMP, ADP and ATP, but not adenosine increased contractile force. None of the purines altered fH. Thus, the adenine nucleotides directly affect the myocardium and not the fH-setting cardiac ganglion.

In cardioregulatory-denervated animals in which the cardiac ganglion only was severed from the central nervous system (CNS), purines caused a small and gradual increase in fH, indicating that in vivo an alteration of fH arises indirectly through the central nervous system which in turn sends the information to the heart via the dorsal nerves. The gradual increase in fH of cardioregulatory-denervated animals may also result from neurohormones released into the circulatory system, although no significant changes in haemolymph concentration of dopamine, serotonin and octopamine were found during adenosine infusion.

In semi-isolated (in situ) hearts adenine nucleotides also increased haemolymph flow, as a consequence of increased heart contractile force, but again adenosine had no effect. These data show that in vivo adenosine does not influence the myocardium, only the adenine nucleotides affect the myocardium directly. Obviously adenosine possesses an indirect effect, perhaps on cardio-arterial valves and arterial resistance, but other, as yet unidentified, modifying factors are also possible.

Key words: adenosine, adenine nucleotides, heart rate, haemolymph velocity, lobster, Homarus americanus


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




© The Company of Biologists Ltd 2008