Abstract
This study examined the effect of 2-week infusion of angiotensin-II (Ang-II; 175. ng/kg/min) via minipump in rats (n=7) upon the mean arterial blood pressure (mBP) and heart rate (HR) response to an acute stress as compared to rats infused with saline (n=7). The acute stress was produced by a classical aversive conditioning paradigm: a 15. s tone (CS. +) followed by a half second tail shock. Baseline mBP in Ang-II infused rats (167.7 ± 21.3. mm Hg; mean ± SD) significantly exceeded that of controls (127.6 ± 13.5. mm Hg). Conversely, baseline HR in the Ang-II infused rats (348 ± 33) was significantly lower than controls (384 ± 19. bpm). The magnitude of the mBP increase during CS. + did not differ between groups, but the HR slowing during CS. + in the Ang-II infused rats (- 13.2 ± 8.9. bpm) was significantly greater than that seen in controls (- 4.2 ± 5.5. bpm). This augmented bradycardia may be inferentially attributed to an accentuated increase in cardiac parasympathetic activity during CS. + in the Ang-II infused rats. The mBP increased above baseline immediately post-shock delivery in controls, but fell in the Ang-II infused rats, perhaps because of a 'ceiling effect' in total vascular resistance. This classical conditioning model of 'acute stress' differs from most stress paradigms in rats in yielding a HR slowing concomitant with a pressor response, and this slowing is potentiated by Ang-II.
Original language | English |
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Pages (from-to) | 42-46 |
Number of pages | 5 |
Journal | Autonomic Neuroscience: Basic and Clinical |
Volume | 174 |
Issue number | 1-2 |
DOIs | |
State | Published - Mar 2013 |
Bibliographical note
Funding Information:Supported by grants RO1 NS39774 and HL073085 from the National Institutes of Health .
Funding
Supported by grants RO1 NS39774 and HL073085 from the National Institutes of Health .
Funders | Funder number |
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National Institutes of Health (NIH) | |
National Heart, Lung, and Blood Institute (NHLBI) | R01HL073085 |
Keywords
- Anxiety
- Classical Pavlovian conditioning
- Hypertension
- Renin angiotensin system (RAS)
ASJC Scopus subject areas
- Endocrine and Autonomic Systems
- Clinical Neurology
- Cellular and Molecular Neuroscience