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ARS Home » Midwest Area » Lexington, Kentucky » Forage-animal Production Research » Research » Publications at this Location » Publication #389395

Research Project: Optimizing the Biology of the Animal-Plant Interface for Improved Sustainability of Forage-Based Animal Enterprises

Location: Forage-animal Production Research

Title: Influence of prolonged serotonin and ergovaline pre-exposure on vasoconstriction ex vivo

item VALENTE, ERITON - University Of Kentucky
item HARMON, DAVID - University Of Kentucky
item Klotz, James

Submitted to: Toxins
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/18/2021
Publication Date: 12/23/2021
Citation: Valente, E.E., Harmon, D.L., Klotz, J.L. 2021. Influence of prolonged serotonin and ergovaline pre-exposure on vasoconstriction ex vivo. Toxins. 14(1):9.

Interpretive Summary: Ergot alkaloids are fungally produced toxins that can be consumed by livestock either through consumption of contaminated grains or grazing infested pastures. These toxins share structural similarities to neurotransmitters such as serotonin and cause disruptions in the normal biological processes associated with the neurotransmitter. One of the functions disrupted by ergot alkaloids is the ability of blood vessels to dilate and contract that is in part regulated by serotonin. This study looked at the interaction of serotonin and the ergot alkaloid ergovaline incubated with bovine lateral saphenous veins for 24-hr prior to assessment of the vasoactivity to serotonin. The findings of the study were that ergot alkaloids were 5000 times more potent than serotonin at inhibiting contractile response of the vein, but that serotonin appears to compete with ergot alkaloids at the serotonin receptor. This research is an important first step in the ex vivo exploration of using serotonin as a possible therapy to treat ergot toxicosis in livestock. The findings of this manuscript will be largely of interest to other researchers.

Technical Abstract: Ergot alkaloid mycotoxins interfere in the many functions associated with serotonergic neuro-transmitters. Therefore, the objective was to evaluate whether the association of 5-HT and ergot alkaloids during a 24-h pre-incubation can affect vascular contractile response to ergot alkaloids. To evaluate 24-h exposure to 5-HT and ergot alkaloids (ergovaline, ERV) two assays were car-ried out. The first assay determined the IC50 following the 24-h pre-exposure period, while the second assay evaluated the effect of IC50 concentrations of 5-HT and ERV either individually or in combination. There was an interaction between previous exposure to 5-HT and ERV. Previous exposure to 5-HT at the IC50 concentration of 7.57 x 10-7 M reduced the contractile response more than 50% of control, while the exposure to ERV at IC50 dose of 1.57 x 10-10 M tended to decrease (P = 0.081) vessel contractility with a response higher than 50% of control. The 24-h previous expo-sure to both 5-HT and ERV did not potentiate the inhibitory response of blood vessels in compar-ison with incubations of each compound alone. These results suggest receptor competition be-tween 5-HT and ERV. More studies are necessary to determine the potential of 5-HT to treat tox-icosis caused by ergot alkaloids.