dc.contributor.author |
Reading, Stacey |
en |
dc.contributor.author |
Barclay, JK |
en |
dc.date.accessioned |
2017-08-16T04:06:32Z |
en |
dc.date.issued |
2002 |
en |
dc.identifier.citation |
Canadian Journal of Physiology and Pharmacology 80(6):569-577 2002 |
en |
dc.identifier.issn |
0008-4212 |
en |
dc.identifier.uri |
http://hdl.handle.net/2292/35137 |
en |
dc.description.abstract |
We tested the hypothesis that nitric oxide has a positive inotropic effect on mammalian cardiac muscle contractility and that this effect sums with the positive inotropic effect of β1-adrenergic agonists when both are present. Feline right ventricular papillary muscles were stimulated to contract isometrically at 0.2 Hz in Krebs Henseleit bicarbonate buffer (KREBS) gassed with 95% O2 and 5% CO2 (26°C; pH 7.34). The nitric oxide (NO) donor, S-nitroso-N-acetylpenicillamine (SNAP, 10 5 M), and the membrane permeable cGMP analog 8-bromoguanosine-3',5'-cyclo phosphate sodium (Br-cGMP, 10 5 M), significantly increased developed force by 13.3 ± 1.5% (n = 11) and 7.8 ± 2.8% (n = 7), respectively. SNAP, at 10-5 M, significantly increased the force developed by papillary muscle treated with 10 11 M or 10 9 M dobutamine hydrochloride (a β1-adrenergic agonist) (n = 25, 11.3 ± 2.9% and 10.0 ± 3.6%, respectively) when compared with the addition of KREBS (n = 27, 2.6 ± 0.9% and 5.5 ± 0.9%), but the increase was less than predicted by the sum of inotropic effects of SNAP and dobutamine. SNAP at 10-5 M did not change developed force in muscles treated with 10 7 M dobutamine but it significantly decreased developed force in muscles challenged with 10 5 M dobutamine (n = 18, 29.3 ± 5.0%) when compared with KREBS (n = 10, 41.5 ± 6.8%). Similarly, 10 4 M 8-bromo-adenosine cyclic 3',5'-hydrogen phosphate monosodium (a membrane permeable cAMP analog) increased developed force 14.9 ± 3.3% and the addition of 10 5 M Br-cGMP to those muscles significantly reduced developed force by 3.5% ± 1.1% (n = 7). Thus, the positive inotropic effect of NO decreased and ultimately became an attenuation as the level of β1-adrenergic stimulation increased due, at least in part, to an interaction between the cAMP and cGMP second messenger pathways.Key words: nitric oxide, β1-adrenergic, cGMP, cAMP, contractility, cardiac muscle. |
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dc.publisher |
NRC Research Press |
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dc.relation.ispartofseries |
Canadian Journal of Physiology and Pharmacology |
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dc.rights |
Items in ResearchSpace are protected by copyright, with all rights reserved, unless otherwise indicated. Previously published items are made available in accordance with the copyright policy of the publisher. |
en |
dc.rights.uri |
https://researchspace.auckland.ac.nz/docs/uoa-docs/rights.htm |
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dc.title |
The inotropic effect of nitric oxide is dependent on the level of beta 1-adrenergic stimulation in isolated mammalian myocardium |
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dc.type |
Journal Article |
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pubs.issue |
6 |
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pubs.begin-page |
569 |
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pubs.volume |
80 |
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dc.rights.holder |
Copyright: NRC Research Press |
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dc.identifier.pmid |
12117306 |
en |
pubs.declined |
2017-06-25T19:48:32.414+1200 |
en |
pubs.end-page |
577 |
en |
dc.rights.accessrights |
http://purl.org/eprint/accessRights/RestrictedAccess |
en |
pubs.subtype |
Article |
en |
pubs.elements-id |
629943 |
en |
pubs.org-id |
Science |
en |
pubs.org-id |
Exercise Sciences |
en |
dc.identifier.eissn |
1205-7541 |
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pubs.record-created-at-source-date |
2017-06-14 |
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pubs.dimensions-id |
12117306 |
en |