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).