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Effect of circulating angiotensin II on central vascular and inflammatory responses in the rat PVN
Author(s) -
Arocha Rebeca,
Zubcevic Jasenka
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.1010.9
Subject(s) - angiotensin ii , saline , medicine , endocrinology , bolus (digestion) , chemistry , blood pressure , microglia , inflammation
High levels of Angiotensin II (Ang II) are associated with hypertension and blood brain barrier (BBB) disturbance. We have previously shown that neuronal effects of a single systemic injection of Ang II persist for several hours after the blood pressure returns to baseline. Thus, we hypothesize that a single injection of Ang II may cause microglial activation via BBB disturbance. Adult male WKY rats were injected with bolus saline or Ang II (40μg/kg in 0.5ml saline i.p.). At one and 24 hours post‐injection, brains were collected (2% PFA), cryoprotected (30% sucrose) and frozen in OTC. Sections (10μm) were cut in the paraventricular nucleus (PVN) region (1.44–1.92mm caudal to Bregma). Slides were incubated with mouse anti‐rat transferrin (ThermoFisher Scientific Catalog#: 13‐6800; 1:450), rabbit anti‐rat IBA1 (Wako Pure Chemical Industries, Ltd. Catalog#: 019‐19741; 1:500), and rabbit anti‐rat GFAP (Sigma‐Aldrich Co. LLC Catalog#: G4546‐100UG; 1:400) overnight. Images were taken with a Zeiss fluorescent microscope and analyzed with imageJ. Transferrin levels reduced at one hour (−31.5±6.11, P=0.0143), returning to baseline levels at 24 hours post‐Ang II (+20.8±11.9, P=0.202). Similarly, a significant increase in number of activated microglia was present at one hour (+28.2±4.316%, P=0.0196), which remained high at 24 hours post Ang II (+16.2±2.57%, P=0.0143). In contrast, no significant changes in astrocytes were observed at one hour (−22.2±19.6, P=0.429) and 24 hours post Ang II (+4.5±19.1, P=0.849). We propose that even a single systemic injection of Ang II may exert its central effects via disturbance of BBB. Support or Funding Information As part of the STRIDE Undergraduate Summer Research Fellowship, the author was funded by the American Physiological Society and a grant from the National Heart, Lung and Blood Institute (NHLBI;1 R25 HL115473‐01). And would like to thank Dr. J Zubcevic for guidance throughout this experiment.