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Mesenteric Artery Contraction and Relaxation Studies Using Automated Wire Myography
Published on: September 22, 2011
Rabbit mononuclear leukocytes cause contraction of isolated aorta by the release of serotonin
J L Hart-Favaloro1, O L Woodman
1Department of Pharmacology, University of Melbourne, Parkville, Australia.
Objective:
The aim of this study was to examine the vasoactive effects of rabbit isolated mononuclear leukocytes, and to identify the mediators responsible for those vasoactive effects.
Methods:
Mononuclear leukocytes (MNLs) were isolated from New Zealand White rabbit whole blood, suspended at 5 x 10(7) cells/ml and incubated for 30 min at 37 degrees C. This cell suspension, or the cell-free supernatant from this suspension, were then examined for vasoactive effects in rabbit isolated thoracic aorta.
Results:
Both the MNL suspension and the cell-free supernatant from this suspension caused endothelium-independent contraction of aortic rings, both from resting tension and when pre-contracted. The MNL suspension caused a significantly greater contraction than the MNL supernatant under all conditions. The contractions to the MNL product were significantly inhibited by the 5-HT2 receptor antagonist ketanserin (0.1 microM), but not by the alpha 1-adrenoceptor antagonist prazosin (10 microM). High-performance liquid chromatography (HPLC) analysis showed that the MNL supernatant contained serotonin (5-hydroxytryptamine, 5-HT) at an average concentration of 5 microM.
Conclusions:
We conclude that MNLs cause contraction of rabbit isolated aortic rings by the release of 5-HT.
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