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

Department of Animal Sciences, University of Missouri, Columbia 65201, USA.
Journal of Animal Science (Impact Factor: 2.09). 06/1995; 73(5):1396-400.
Source: 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.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Case reportPerennial ryegrass toxicosis (PRGT) is a common disease entity in Australia, presenting as an association of clinical signs including alterations in normal behavioural, ataxia (‘staggers’), ill thrift and gastrointestinal dysfunction (‘scours’). Clinical signs can range in severity from mild (gait abnormalities and failure to thrive) to severe (seizures, lateral recumbency and death). Presentation across the flock is usually highly variable. PRGT is caused by toxins produced by the endophytic fungus Neotyphodium lolii, a symbiont of perennial ryegrass that is present in pastures across the temperate regions of Australia and Tasmania. A particular feature of PRGT in Australia is the occasional occurrence of large-scale sheep losses, suggesting other factors are influencing mortality rates compared with other PRGT risk zones such as North America and New Zealand. During 2011, producers in the state of Victoria experienced a mild outbreak of PRGT that affected large numbers of animals but with limited mortalities. Clinical samples taken from affected sheep showed a high incidence of dehydration and electrolyte abnormalities.Conclusion We speculate that changes in hydration status may be a contributory aetiological factor in those years in which high numbers of deaths are associated with PRGT outbreaks in Australia.
    Australian Veterinary Journal 04/2014; 92(4). · 0.92 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background. The pathophysiology of migraine remains unclear but the development of more specific drugs against migraine has revealed new insights into the structures and mechanisms involved. The efficacy of these new drugs varies among patients. In this study we assessed the efficacy of metoclopramide in comparison with sumatriptan to alleviate the acute phase of migraine. Hypothesis. Metoclopramide is more effective than sumatriptan as migraine abortive therapy. Methods. One hundred and twenty patients ranging from 18 to 65 years of age were divided at random into two groups. One group received 10 mg of metoclopramide (IV, three min), and the other group 6 mg of sumatriptan (subcutaneously, slowly). We registered the time course of pain decrease and the main secondary effects. Data were analyzed by X 2 with a significance level of
  • [Show abstract] [Hide abstract]
    ABSTRACT: The geoheritages landscape resources in xinjiang are great in quantity, vary in type and excellent in grade. The geoheritages landscape resources can be classified into 7 different types and 28 subtypes in xinjiang. The old Model of Geoheritages management can no longer meet the demands of fast development. Therefore, An Optimization Model of Geoheritages landscape resources management is put forward in this paper based on the view of Benefit- Sharing in Xinjiang. In The Optimization Model, geological heritages landscape resources can get Optimization at last, by government centered management, capitalized management, ecosystems management conception, wellcycling protection and exploitation management model, benefit-sharing mechanism innovation and geological tourism network with geopark as its center.
    Energy Procedia 01/2011; 5:1060-1064.

Full-text (2 Sources)

Available from
Jul 31, 2014