Effect of 5-hydroxytryptamine-2 and alpha-adrenergic receptor antagonists on the 5-hydroxytryptamine-induced decrease in rabbit masseter muscle blood flow.
A previous study showed a significant decrease in blood flow in the rabbit masseter during infusion of 5-hydroxytryptamine (5-HT) (10(-9) mol/l). The aim of the present study was to test the hypothesis that blockade of the 5-HT2 or the alpha-adrenergic receptor would inhibit the 5-HT-induced decrease of microcirculatory blood flow in the masseter. In 12 rabbits, the masseters were infused with 5-HT (10(-9) mol/l) in combination with the alpha-adrenoceptor antagonist phentolamine (10(-6) mol/l) or the 5-HT2-receptor antagonist ritanserin (10(-6) mol/l). The effect on microcirculatory blood flow was measured by laser-Doppler flowmetry. Infusion of 5-HT induced a significant decrease in blood flow. Inclusion of ritanserin in the 5-HT infusion solution significantly inhibited this decrease, while inclusion of phentolamine did not. This study therefore showed that the 5-HT2 receptor antagonist ritanserin inhibited the 5-HT-induced decrease in microcirculatory blood flow in the rabbit masseter. This decrease in blood flow is thus mediated by the 5-HT2 receptor.
Kurita
H
H
Department of Clinical Oral Physiology, Faculty of Dentistry, Karolinska Institutet, Huddinge, Sweden. hkurita@hsp.md.shinshu-u.ac.ip
Ernberg
M
M
Tominaga
K
K
Alstergren
P
P
Kopp
S
S
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects; D017078:Laser-Doppler Flowmetry; D008297:Male; D008406:Masseter Muscle / Q000098:blood supply* / Q000187:drug effects*; D008833:Microcirculation / Q000187:drug effects; D010646:Phentolamine / Q000494:pharmacology; D011817:Rabbits; D016713:Ritanserin / Q000494:pharmacology; D012701:Serotonin / Q000494:pharmacology*; D012702:Serotonin Antagonists / Q000494:pharmacology*; D013997:Time Factors
D000317:Adrenergic alpha-Antagonists; D012702:Serotonin Antagonists; D016713:Ritanserin; D012701:Serotonin; D010646:Phentolamine