Effect of 5-hydroxytryptamine infusion on microcirculation in the rabbit masseter muscle measured by laser-Doppler flowmetry

The aim was to test the hypothesis that 5-hydroxytryptamine (5-HT) influences the microcirculation of the masseter muscle. Rabbit masseters were infused with increasing concentrations of 5-HT (10(-9)-10(-5) M) on the experimental side and with saline on the control side. The effect on microcirculatory blood flow was measured by laser-Doppler flowmetry. The intramuscular temperature was recorded to monitor the influence of tissue temperature. 5-HT infusion resulted in a statistically significant decrease in blood flow at the lowest concentration (10(-9) M) (median; -11.2%. Wilcoxon signed-rank test; p < 0.05). At concentrations greater than 10(-9) M, there was no significant change in blood flow. This study shows a decrease of microcirculatory blood flow in the rabbit masseter following 5-HT infusion (10(-9) M). (C) 1999 Elsevier Science Ltd. All rights reserved.