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]
- 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 UnknownAgonistDetails