Ergovaline binding and activation of D2 dopamine receptors in GH4ZR7 cells.

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Larson BT, Samford MD, Camden JM, Piper EL, Kerley MS, Paterson JA, Turner JT

Ergovaline binding and activation of D2 dopamine receptors in GH4ZR7 cells.

J Anim Sci. 1995 May;73(5):1396-400.

PubMed ID

7665369 [ View in PubMed

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Abstract

Ergovaline inhibition of radioligand binding to the D2 dopamine receptor and ergot alkaloid inhibition of vasoactive intestinal peptide (VIP)-stimulated cyclic AMP production in GH4ZR7 cells, stably transfected with a rat D2 dopamine receptor, were evaluated. Ergovaline inhibition of the binding of the D2-specific radioligand, [3H]YM-09151-2, exhibited a KI (inhibition constant) of 6.9 +/- 2.6 nM, whereas dopamine was much less potent (370 +/- 160 nM). Ergot alkaloids were also effective in inhibiting VIP-stimulated cyclic AMP production, with EC50 values for ergovaline, ergonovine, alpha-ergocryptine, ergotamine, and dopamine of 8 +/- 2, 47 +/- 2, 28 +/- 2, 2 +/- 1, and 8 +/- 1 nM, respectively. Inhibition of cyclic AMP production by ergovaline was blocked by the dopamine receptor antagonist, (-)-sulpiride (IC50, 300 +/- 150 nM). Our results indicate that ergot compounds, especially ergovaline, bind to D2 dopamine receptors and elicit second messenger responses similar to that of dopamine. These findings suggest that some of the deleterious effects of consumption of endophyte-infected tall fescue, which contains several ergot alkaloids including ergovaline, may be due to D2 dopamine receptor activation.

DrugBank Data that Cites this Article

Drug Targets

Drug	Target	Kind	Organism	Pharmacological Action	Actions
Ergotamine	Dopamine D2 receptor	Protein	Humans	Unknown	Agonist	Details