INTERACTIONS BETWEEN 5-HYDROXYTRYPTAMINE, NORADRENALINE AND THE THROMBOXANE-A2 MIMETIC U44069 IN THE MARMOSET ISOLATED AORTA
Dyer, S. M. ; Bexis, S. ; Mano, M. T. ; Lande, I. S. ; Frewin, D. B. ; Head, R. J.
Oxford, UK : Blackwell Publishing Ltd
Published 1994
Oxford, UK : Blackwell Publishing Ltd
Published 1994
| ISSN: |
1440-1681
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|---|---|
| Source: |
Blackwell Publishing Journal Backfiles 1879-2005
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| Topics: |
Medicine
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| Notes: |
1. The effects of 5-hydroxytryptamine (5-HT) in the absence and presence of noradrenaline (NA) or the thromboxane-A2 mimetic, U44069, were investigated in ring preparations of marmoset aorta.2. 5-HT (0.001-10 μmol/L) produced little or no contractile response in preparations at basal tone. When the tone was elevated to 50% of maximum with NA the predominant response to 5-HT was relaxation. The 5-HT2 receptor antagonist LY53857 (0.1 μmol/L) unmasked a contractile response to low concentrations of 5-HT (0.01 - 1.0 μmol/L) and reduced relaxation to high concentrations of 5-HT (1.0-10 μmol/L) in vessels precontracted with NA.3. In U44069-contracted vessels, 5-HT was contractile in the range 0.01-1 μmol/L and relaxant in concentrations of 6.0-10.0 μmol/L. Ketanserin (1.0 μmol/L) had no effect on the contraction or relaxation to 5-HT.4. The relaxant response to 5-HT was not significantly diminished in endothelium-impaired arteries.5. In conclusion, 5-HT exerts complex inhibitory and excitatory actions on the marmoset aorta. The inhibitory actions are not endothelium-dependent and the excitatory actions do not appear to involve the 5-HT2 receptor.
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| Type of Medium: |
Electronic Resource
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| URL: |