Serotonin and superior mesenteric artery resistance index

Abstract

We conclude that intravenous infusion of serotonin increases the resistance index of the superior mesenteric artery (increases downstream resistance) in healthy adult volunteers.

Are Splanchnic Hemodynamics Related to the Development of Gastrointestinal Symptoms in Ironman Triathletes? A Prospective Cohort Study

“…11,12,25 In some studies, RI has been used to assess hemodynamics in the SMA. 21,23 In our study, RI of the SMA and coeliac artery was significantly decreased in triathletes after the race, and this reduced RI suggests mesenteric hyperemia (an increase in blood flow). To our knowledge, this is the first study using RI as a measure of blood flow after prolonged exercise, and therefore, our findings cannot be compared with those from other similar studies.…”

“…In one other study where RI was used as a measure of blood flow, blood pressure changes were not measured. 21 Other possible mechanisms that may have contributed to a reduced RI are the response to food or fluid intake and variations in other neurotransmitter concentrations, such as 5-hydroxytryptamine. 21 Our study was not designed to measure these parameters as possible mechanisms, and therefore, further studies are required to determine if these mechanisms could explain our observed changes in RI.…”

“…21 Other possible mechanisms that may have contributed to a reduced RI are the response to food or fluid intake and variations in other neurotransmitter concentrations, such as 5-hydroxytryptamine. 21 Our study was not designed to measure these parameters as possible mechanisms, and therefore, further studies are required to determine if these mechanisms could explain our observed changes in RI. However, the results from our study do seem to support the observations from other prospective cohort studies, which showed the physiological vasoconstriction of the SMA that occurs during and immediately after an exercise.…”

“…Doppler ultrasound is recognized as a valuable tool for the assessment of blood flow in a number of vascular areas. 14 This technique has been used successfully in the hemodynamic assessment of SMA and coeliac artery blood flow at rest, [20][21][22] during exercise, 23 and immediately after exercise. [13][14][15][16][17][18][19] This technique is reported to have a high predictive value in the detection of mesenteric artery disease.…”

“…Resistive index (RI) was calculated as follows: RI = (systolic velocity 2 diastolic velocity)/systolic velocity. 21 Sixty-four triathletes underwent prerace and postrace hemodynamic assessment of the SMA and coeliac artery. Five of the triathletes were excluded due to GI symptoms in the 3 days leading up to the race.…”