Ergot alkaloids physiological effects

The source of the ergot strongly influences the type of alkaloids present, as well as the clinical picture of ergotism [171]. The ergot alkaloids have three types of physiological effects they cause contraction of smooth muscle, they block the action of serotonin and adrenaline, and they act on the hypothalamic-pituitary system to inhibit the secretion of prolactin. These properties have led to their being used to induce uterine contractions, to relieve migraine headaches, and to treat prolactin-dependent disorders. 

Autacoids are endogenous molecules with powerful pharmacologic effects but poorly defined physiologic roles. Histamine and serotonin (5-hydroxytryptamine 5-HT) are two of the most important autacoids. Both are synthesized in the body from amino acid precursors and then eliminated by amine oxidation the pathways of synthesis and metabolism are very similar to those used for catecholamine synthesis and metabolism. The ergot alkaloids are a heterogeneous group of drugs that interact with serotonin receptors, dopamine receptors, and alpha receptors. They are included in this chapter because of their effects on serotonin receptors and on smooth muscle. 

The various physiological activities of the ergot alkaloids can be divided into three types. The peripheral effects are the contraction of smooth muscle including the peripheral blood vessels and the muscle of the uterus. 

Robbers, J.E., Eggert, W.W. and Floss, H.G. (1978) Physiological studies on ergot. Time factor influence on the inhibitory effect of phosphate and the induction effect of tryptophan on alkaloid production. Lloydia, 41,120-129. 

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