Angiotensin-(1-7) antagonist [D-Ala7-Ang-(1-7);A-779] attenuates post-suspension hypotension in Sprague-Dawley rats.
Cardiovascular deconditioning manifested by reduction in mean arterial pressure (MAP) and cardioaccleration are usually observed in astronauts during standing postflight. The head-down tilt (HDT) rat model with "unloaded" hindlimbs has been extensively studied because some of the observed responses mimic observations made during exposure to microgravity. Angiotensin-(1-7) is a biologically active component of the renin-angiotensin system that acts to oppose the pressor and proliferative actions of Angiotensin II. It produces a hypotensive response by either stimulating production of vasodilator prostaglandins (i.e., prostacyclin), increasing nitric oxide or both. In the present study, we have evaluated the role of a specific inhibitor of Ang-(1-7), D-Ala7-Ang-(1-7)[A-779], as a countermeasure against post-suspension hypotension.
Bayorh
M A
MA
Departments of Pharmacology/Toxicology, Morehouse School of Medicine, Atlanta, Georgia, USA.
Wang
M
M
Socci
R R
RR
Eatman
D
D
Emmett
N
N
Thierry-Palmer
M
M
D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D006339:Heart Rate; D019417:Hindlimb Suspension; D007024:Hypotension, Orthostatic / Q000517:prevention & control; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018544:Weightlessness Countermeasures; D018474:Weightlessness Simulation
C092006:7-Ala-angiotensin (1-7); D010446:Peptide Fragments; D000804:Angiotensin II