Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020538 (hypertension)
 170,190 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Blood-brain barrier (BBB) alterations following acute hypertension were studied in rats, employing as tracers in each animal both horseradish peroxidase (HRP) (MW 40,000) and [14C]alpha-aminoisobutyric acid ([14C]AIB) (MW 104). Eighteen animals were subjected to acute hypertension induced by the intravenous infusion of norepinephrine bitartrate (NE) (Levophed). Five animals injected with both tracers but not infused with NE served as controls. The brain of each animal was serially sectioned with adjacent sections processed either for macroautoradiography or for light microscopic visualization of HRP reaction product via histochemical reaction with tetramethylbenzidine. Quantitative blood-to-brain transfer constants for AIB were determined in each of 14 brain regions. Qualitative comparisons were also made between the AIB and HRP blood-to-brain extravasation patterns in each group. Acute hypertension increased cerebrovascular permeability to both AIB and HRP in most animals. Topographically, the sites of the most highly elevated AIB transfer corresponded with sites of HRP extravasation. Conversely, all sites of protein passage corresponded spatially to sites of elevated AIB transfer. Brain regions commonly showing increased permeability to both tracers included the cerebral cortices, corpus callosum, and thalamus. Importantly, some brain regions showed elevated AIB transfer constants where protein extravasation was absent. These regions included the caudate-putamen, hippocampus, basal forebrain, and cerebellum. These observations suggest that following acute hypertension, alterations in BBB permeability are not limited to vascular segments allowing protein extravasation.
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PMID:Examination of the blood-to-brain transfer of alpha-aminoisobutyric acid and horseradish peroxidase: regional alterations in blood-brain barrier function following acute hypertension. 373 5

Magnesium sulfate is primarily used for its anticonvulsive effects in treating hypertensive disorders of pregnancy. However, we have frequently observed significant falls in blood pressure in patients suffering from severe pregnancy-induced hypertension in whom little or no additional hypotensive medication was necessary for maintenance of diastolic blood pressure at 90 to 100 mm Hg while using recommended doses of this drug. We compared resting mean arterial pressure and vascular response to infusions of 50 ng/kg/min of angiotensin II and 2500 ng/kg/min of Levophed (norepinephrine) before and during infusion of a loading dose of 200 mg of magnesium sulfate intravenously in 15 minutes, followed by continuous infusions of 50 and 100 mg/hr intravenously in chronically prepared virgin (n = 14) and primigravid (n = 12) rabbits at 24 to 28 days' gestation (term = 30 +/- 1 day). Resting mean arterial pressure and vascular response to angiotensin II and norepinephrine were significantly decreased in the primigravid and virgin animals. Magnesium sulfate may attenuate blood pressure by decreasing the vascular response to pressor substances.
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PMID:The effects of magnesium sulfate infusion on blood pressure and vascular responsiveness during pregnancy. 646 20