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Potentiation of angiotensin II (Ang II) hypertension in rats by sensitizing pre‐treatment with intermittent ICV Ang II injections
Author(s) -
Clayton Sarah C,
Hurley Seth,
Beltz Terry,
Johnson Alan Kim
Publication year - 2013
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.27.1_supplement.904.7
Subject(s) - angiotensin ii , medicine , endocrinology , blood pressure , cannula , sensitization , stimulation , thirst , renin–angiotensin system , chemistry , surgery , immunology
Previous work from our lab has shown the potentiated effect of pre‐treatment with subpressor infusion of Ang II on the hypertensive response to a pressor dose of Ang II. Other studies in the sensitization field have shown intermittent brain stimulation has an effect to increase Ang II related responses, i.e. thirst. We hypothesized that intermittent injection of subpressor Ang II would also sensitize the blood pressure (BP) response to a pressor dose of Ang II. To study this hypothesis, we instrumented rats with radiotelemetry devices to measure BP and ICV cannula for Ang II injection and employed an Induction‐Delay‐Expression (I‐D‐E) experimental design. Rats were allowed to recover for one week before baseline recordings were made (B). After B, rats were injected with 10 ng Ang II in 4 μl ICV on days 1, 3, 5, 7 (I). Rats were then rested an additional 7 days (D); after D, rats were implanted with osmotic minipumps to deliver Ang II (120 ng/kg/min, sc) continuously for 2 weeks (E). No difference in BP was detected during B, I, or D in either group. BP increased during E in both groups (sham: 111±3 mmHg, B, vs. 126±3 mmHg, E; pre‐Ang II: 105±4 mmHg, B, vs. 140±7 mmHg, E); however, this increase was potentiated in rats with intermittent Ang II injections (delta: 15±5 mmHg, sham, vs. 35±5, pre‐Ang II, P=0.03). These results document the ability of central intermittent Ang II injections to sensitize the BP response to systemic Ang II.