Possible Interaction: Epinephrine and Serotonin

“Significant negative linear correlations between serotonin and FSH (r = -0.45; p < 0.001), serotonin and daily excretion of adrenaline (r = -0.43; p < 0.01) or noradrenaline (r = -0.58; p < 0.001) were disclosed in the exposed group.”

“In vivo and in vitro studies have shown that 5-HT stimulates mineralo- and glucocorticoid secretion from adrenal cells.”

“Abstract Adrenochrome formation from epinephrine is either accelerated or inhibited by serotonin , the effect being dependent on the relative concentrations of the indoleamine compared to the catecholamine.”

“Responses to dexamphetamine and 5-hydroxytryptamine were blocked in preparations protected by adrenaline.”

“In a population of healthy subjects, co-stimulation with submaximal concentrations of epinephrine and serotonin identifies a subset of individuals with a hyperreactive platelet aggregation profile that is associated with changes in platelet serotonin function.”

“Subjects with heightened (>60%) platelet aggregation to both epinephrine alone and epinephrine plus serotonin exhibited increased platelet serotonin uptake, and transporter number and affinity.”

“Here we studied the mechanism of synergistic interaction of 5-hydroxytryptamine (5-HT) and epinephrine mediated platelet aggregation.”

“The … 5-HT (1-…) and epinephrine (0.5-2 microM) was inhibited by alpha2-adrenoceptor blocker (yohimbine; IC50= 0.4 microM), calcium channel blockers (verapamil and diltiazem with … 10 and 48 mM, respectively), PLC inhibitor (U73122; IC50=6 microM) and nitric oxide (NO) donor, SNAP (IC50=1.6 microM)).”

“We show that 5-HT had no or little effect on aggregation but it did potentiate the aggregation response of epinephrine.”

“Consistent with these observations, the combination of serotonin (a Gαq pathway stimulator) and epinephrine (a Gαz pathway stimulator) also caused α granule release.”

“However, in 2 cases, simultaneous application of 5-HT and epinephrine produced both first- and second-phase platelet aggregation.”

“These demonstrated first-phase aggregation in 40% of cases when both 5-HT and epinephrine were applied simultaneously, while in the majority of the newborns no reaction was encountered when each of these substances was applied separately.”

“However, when a lower concentration of adrenaline (0.2 mumol/l) was added in combination with a dose of serotonin (0.02 mumol/l) that did not affect the MPV on its own, the measured MPV increased significantly and the EM showed pseudopodia formation.”

“A marked potentiation of the aggregation induced by subthreshold concentrations of adrenaline resulted from the prior addition of low concentrations of ADP, collagen or serotonin.”