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Effect of 5-hydroxytryptamine-2 and alpha-adrenergic receptor antagonists on the 5-hydroxytryptamine-induced decrease
H Kurita1, M Ernberg, K Tominaga
1Department of Clinical Oral Physiology, Faculty of Dentistry, Karolinska Institutet, Huddinge, Sweden. hkurita@hsp.md.shinshu-u.ac.ip
Archives of Oral Biology
|August 25, 1999
Summary
The 5-hydroxytryptamine (5-HT) induced decrease in rabbit masseter blood flow is mediated by the 5-HT2 receptor. Ritanserin, a 5-HT2 receptor antagonist, inhibited this blood flow reduction.
Area of Science:
- Physiology
- Pharmacology
- Microcirculation Research
Background:
- Previous research indicated 5-hydroxytryptamine (5-HT) reduces blood flow in the rabbit masseter.
- The specific receptors mediating this effect remained unclear.
Purpose of the Study:
- To investigate whether 5-HT2 or alpha-adrenergic receptors are responsible for the 5-HT-induced decrease in masseter microcirculatory blood flow.
- To test the hypothesis that blocking these receptors would inhibit the blood flow reduction.
Main Methods:
- Microcirculatory blood flow in rabbit masseters was measured using laser-Doppler flowmetry.
- 5-HT was infused alone or combined with either the 5-HT2 antagonist ritanserin or the alpha-adrenoceptor antagonist phentolamine.
Main Results:
- 5-HT infusion significantly decreased masseter blood flow.
- Ritanserin significantly inhibited the 5-HT-induced blood flow decrease.
- Phentolamine did not inhibit the 5-HT-induced blood flow decrease.
Conclusions:
- The 5-HT-induced reduction in rabbit masseter microcirculatory blood flow is primarily mediated by the 5-HT2 receptor.
- Targeting the 5-HT2 receptor with antagonists like ritanserin can inhibit this vasoconstrictive effect.