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Modulation of intra...
Modulation of intracellular Ca2+ via L-type calcium channels in heart cells by the autoantibody directed against the second extracellular loop of the alpha1-adrenoceptors.
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Bkaily, Ghassan (författare)
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El-Bizri, Nesrine (författare)
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Bui, Michel (författare)
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Sukarieh, Rami (författare)
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Jacques, Danielle (författare)
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- Fu, Michael, 1963 (författare)
- Gothenburg University,Göteborgs universitet,Wallenberglaboratoriet,Wallenberg Laboratory
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(creator_code:org_t)
- Canadian Science Publishing, 2003
- 2003
- Engelska.
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Ingår i: Canadian journal of physiology and pharmacology. - : Canadian Science Publishing. - 0008-4212 .- 1205-7541. ; 81:3, s. 234-46
- Relaterad länk:
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https://gup.ub.gu.se...
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https://doi.org/10.1...
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Abstract
Ämnesord
Stäng
- The effects of methoxamine, a selective alpha1-adrenergic receptor agonist, and the autoantibody directed against the second extracellular loop of alpha1-adrenoceptors were studied on intracellular free Ca2+ levels using confocal microscopy and ionic currents using the whole-cell patch clamp technique in single cells of 10-day-old embryonic chick and 20-week-old fetal human hearts. We observed that like methoxamine, the autoantibody directed against the second extracellular loop of alpha1-adrenoreceptors significantly increased the L-type calcium current (I(Ca(L))) but had no effect on the T-type calcium current (I(Ca(T))), the delayed outward potassium current, or the fast sodium current. This effect of the autoantibody was prevented by a prestimulation of the receptors with methoxamine and vice versa. Moreover, treating the cells with prazosin, a selective alpha1-adrenergic receptor antagonist blocked the methoxamine and the autoantibody-induced increase in I(Ca(L)), respectively. In absence of prazosin, both methoxamine and the autoantibody showed a substantial enhancement in the frequency of cell contraction and that of the concomitant cytosolic and nuclear free Ca2+ variations. The subsequent addition of nifedipine, a specific L-type Ca2+ channel blocker, reversed not only the methoxamine or the autoantibody-induced effect but also completely abolished cell contraction. These results demonstrated that functional alpha1-adrenoceptors exist in both 10-day-old embryonic chick and 20-week-old human fetal hearts and that the autoantibody directed against the second extracellular loop of this type of receptors plays an important role in stimulating their activity via activation of L-type calcium channels. This loop seems to have a functional significance by being the target of alpha1-receptor agonists like methoxamine.
Ämnesord
- MEDICIN OCH HÄLSOVETENSKAP -- Medicinska och farmaceutiska grundvetenskaper -- Mikrobiologi inom det medicinska området (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Microbiology in the medical area (hsv//eng)
- MEDICIN OCH HÄLSOVETENSKAP -- Medicinska och farmaceutiska grundvetenskaper -- Cell- och molekylärbiologi (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Cell and Molecular Biology (hsv//eng)
- MEDICIN OCH HÄLSOVETENSKAP -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)
- MEDICAL AND HEALTH SCIENCES -- Basic Medicine -- Physiology (hsv//eng)
Nyckelord
- Aniline Compounds
- Animals
- Autoantibodies
- pharmacology
- Calcium
- metabolism
- Calcium Channel Blockers
- pharmacology
- Calcium Channels
- L-Type
- physiology
- Calcium Channels
- T-Type
- physiology
- Cells
- Cultured
- Chick Embryo
- Fetus
- Fluorescent Dyes
- Humans
- Methoxamine
- pharmacology
- Myocardial Contraction
- Myocytes
- Cardiac
- drug effects
- physiology
- Nifedipine
- pharmacology
- Patch-Clamp Techniques
- Potassium Channels
- drug effects
- physiology
- Receptors
- Adrenergic
- alpha-1
- agonists
- immunology
- physiology
- Sodium Channels
- drug effects
- physiology
- Xanthenes
Publikations- och innehållstyp
- ref (ämneskategori)
- art (ämneskategori)
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