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|Title: ||Metoprolol Impairs Mesenteric and Posterior Cerebral Artery Function in Mice|
|Authors: ||El Beheiry, Mostafa Hossam|
|Advisor: ||Hare, Gregory|
Bolz, Steffen Sebastian
|Keywords: ||mesenteric resistance artery|
posterior cerebral artery
|Issue Date: ||31-Dec-2010|
|Abstract: ||Background/Rationale: In addition to their established cardioprotective role, β-adrenergic antagonists also increase the risk of stroke and mortality. We propose that a vascular mechanism could contribute to cerebral tissue ischemia in β-blocked patients.
Methods: Cardiac output (CO), mean arterial pressure (MAP) and microvascular brain oxygen tension (PBrmvO2) were measured in anesthesized mice treated with metoprolol (3mg•kg-1, i.v.). Dose-response curves (DRCs) for adrenergic-agonists were generated in mesenteric resistance arteries (MRAs; isoproterenol, clenbuterol) and posterior cerebral arteries (PCAs; phenylephrine, isoproterenol) before and after metoprolol treatment.
Results: Metoprolol reduced CO, maintained MAP and increased systemic vascular resistance (SVR) resulting in a decreased PBrmvO2 in mice. Metoprolol attenuated β-adrenergic mediated vasodilation in both MRAs and PCAs.
Conclusions: Metoprolol reduced brain perfusion in mice. A decrease in CO contributed however, metoprolol also inhibited β-adrenergic vasodilation of mesenteric and cerebral arteries. This provides evidence in support of a vascular mechanism for cerebral ischemia in β-blocked patients.|
|Appears in Collections:||Master|
Department of Physiology - Master theses
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