Modulation of cerebral calcium homeostasis in rats by angiotensin II in vivo.
The uptake of 45Ca2+ by different regions of the brain was determined in anaesthetised rat after infusing angiotensin II (AII; 14 micrograms in 1 ml) through the carotid artery. The control animals (C) were infused with physiological saline. 45Ca2+ was injected in the tail vein 2 min after the infusion of AII or saline. Plasma radioactivity was monitored until euthanasia at different times post injection when the cerebral uptake of 45Ca2+ was determined. While the plasma turnover of 45Ca2+ was similar in AII and C animals, the uptake was markedly higher in AII vs. C at the different brain sites at all times. Kinetic analysis suggested that AII induced a short term increase in Ca2+ transport across the blood-brain barrier and also in the cellular uptake. The effect of AII was receptor mediated being abolished by saralasin, an AII antagonist, and appeared to be at least in part independent of its pressor effect.
Das
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National Center for the Design of Molecular Function, Utah State University, Logan 84322-4105, USA.
Ghosh
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S
D000804:Angiotensin II / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D001692:Biological Transport; D001812:Blood-Brain Barrier; D001921:Brain / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D006706:Homeostasis / Q000187:drug effects*; D007700:Kinetics; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012016:Reference Values; D012504:Saralasin / Q000494:pharmacology; D014018:Tissue Distribution
D000804:Angiotensin II; D012504:Saralasin; D002118:Calcium