The role of DA1‐ and DA2‐receptors in the control of blood pressure.

Hieble, J. Paul; Eden, R. J.; Mey, Christian de

doi:10.1111/j.1365-2125.1990.tb05470.x

Cited by 2 publications

(3 citation statements)

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“…2) analogous to biogenic amines. This feature allows ergot alkaloids to interact in a non-specific manner with a wide range of different receptor molecules, including catecholamine and serotonin, thus causing perturbations to a wide range of physiological functions associated with these receptors [15][16][17][18]23 . The ergopeptides, ergovaline and ergotamine, exhibit vasoconstrictive properties based on in vitro assays [24][25][26][27][28][29][30][31][32][33] .…”

Section: Discussionmentioning

confidence: 99%

“…The ergoline nucleus (Fig. 2) of ergot alkaloids is structurally similar to the biogenic amines, dopamine, serotonin and adrenaline and consequently ergot alkaloids are able to act on the respective receptors, dopaminergic (D), serotonergic (5-HT) and adrenergic [15][16][17][18] . Since ergot alkaloids interact as agonists or antagonists at the various monoamine neurotransmitter receptor sites with no specificity, perturbations in a wide range of downstream physiological functions are associated with the activation of these receptors 19,20 .…”

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confidence: 99%

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Ergot alkaloid mycotoxins: physiological effects, metabolism and distribution of the residual toxin in mice

Reddy

Hemsworth

Guthridge

et al. 2020

Sci Rep

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The complex ergot alkaloids, ergovaline and ergotamine, cause dysregulation of physiological functions, characterised by vasoconstriction as well as thermoregulatory and cardiovascular effects in grazing livestock. To assess the effect of the mycotoxins, blood pressure and heart rate of male mice were measured, and metabolite profiling undertaken to determine relative abundances of both ergotamine and its metabolic products in body and brain tissue. Ergotamine showed similar cardiovascular effects to ergovaline, causing elevations in blood pressure and reduced heart rate. Bradycardia was preserved at low-levels of ergovaline despite no changes in blood pressure. Ergotamine was identified in kidney, liver and brainstem but not in other regions of the brain, which indicates region-specific effects of the toxin. The structural configuration of two biotransformation products of ergotamine were determined and identified in the liver and kidney, but not the brain. Thus, the dysregulation in respiratory, thermoregulatory, cardiac and vasomotor function, evoked by ergot alkaloids in animals observed in various studies, could be partially explained by dysfunction in the autonomic nervous system, located in the brainstem. Ergot alkaloids are produced by certain members of the Clavicipitaceae, including Epichloë, Claviceps, Balansia and Periglandula, as well as the human pathogen Aspergillus fumigatus 1. An array of ergot alkaloids produced by Epichloë endophytes, such as Epichloë festucae var. lolii and Epichloë coenophialum, are commonly found in pasture-based agriculture as they confer benefits to pasture production. Due to its impact on livestock welfare, the best characterised ergot alkaloid producing fungus is E. coenophialum, an endophyte associated with tall fescue grass (Lolium arundinaceum). Ergovaline (Fig. 1) is the major endophyte-derived ergopeptine alkaloid in infected tall fescue and the causative agent of fescue toxicosis or "fescue foot". Tall fescue grasses can also be infected with the parasitic fungus Claviceps purpurea. The major ergopeptide produced by C. purpurea is ergotamine (Fig. 1) which is the main causative agent for the disease "ergotism". These ergopeptides cause vasoconstriction, affecting the animals ability to control body temperature causing conditions called "fescue foot" in colder temperatures and "summer slump" in hot weather 2,3. "Fescue foot" is the result of a reduction of blood flow to the periphery of the animal, affecting thermoregulation and causing dry gangrene (tissue death) 4-6. Animals with this condition show lameness and swelling of the legs, and eventually loss of the tips of the tail or ears and sloughing of the hooves typically from prolonged exposure to the alkaloids. Summer slump indicates hyperthermia or a rise in the animals internal body temperature. Thus, animals spend more time standing in water or shade in order to cool off. Other clinical signs of fescue toxicosis include poor weight gain from reduced feed intake, decreased fertility, and poor milk production 7...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Ergot alkaloid mycotoxins: physiological effects, metabolism and distribution of the residual toxin in mice

Reddy

Hemsworth

Guthridge

et al. 2020

Sci Rep

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“…These ligandreceptor interactions are thought to be the principal mechanism by which ergot alkaloids affect animal performance to mediate their negative effects . For example, activation of the type-2 dopamine receptor (D2) is thought to mediate many of the wholeanimal physiological symptoms observed in tall fescue toxicosis, including intracellular alteration of cardiovascular (Hieble et al, 1990), thermoregulatory (Nunes et al, 1991;Sanchez and Arnt, 1992) and nervous systems (Tomé et al, 2004). Activation of D2 stimulates the inhibitory C protein protein cascade, which inhibits adenylate cyclase activity and, consequently, reduces intracellular cAMP conentrations.…”

Section: Known and Potential Regulation Of Cellular Transport Mechanimentioning

confidence: 99%

BOARD-INVITED REVIEW: St. Anthony's Fire in livestock: Causes, mechanisms, and potential solutions1,2

Strickland

Looper

Matthews

et al. 2011

Journal of Animal Science

177

176

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After a brief history of ergot alkaloids and ergotism, this review focuses on the metabolism and mechanisms of action of the ergot alkaloids. The authors provide models of how these alkaloids afflict grazing livestock under complex animal-plant/endophyte-environmental interactions. Alkaloid chemistry is presented to orient the reader to the structure-function relationships that are known to exist. Where appropriate, the medical literature is used to aid interpretation of livestock research and to provide insight into potential modes of action and alkaloid metabolism where these are not known for livestock. In closing the paper, we discuss management of ergot alkaloid intoxication in livestock and future research needs for this field of study.

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The role of DA1‐ and DA2‐receptors in the control of blood pressure.

Cited by 2 publications

References 20 publications

Ergot alkaloid mycotoxins: physiological effects, metabolism and distribution of the residual toxin in mice

Ergot alkaloid mycotoxins: physiological effects, metabolism and distribution of the residual toxin in mice

BOARD-INVITED REVIEW: St. Anthony's Fire in livestock: Causes, mechanisms, and potential solutions1,2

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