title: The effects of the antagonists of the renin-angiotensin system on cardiovascular response to lower-body subatmospheric pressure in the anaesthetized cat.
abstract: 1. Lower-body subatmospheric (negative) pressure led to a prompt reduction in central venous pressure and arterial blood pressure. Arterial blood pressure was then restored within 30 s and there was a tachycardia. These reflex responses have been used to investigate the role angiotensin plays in blood pressure control. 2. The initial plasma renin activity (2.9 ng of angiotensin I h-1 ml-1) did not change during the brief lowering of pressure. Before pressure was lowered neither the angiotensin-converting enzyme inhibitor nor a competitive antagonist, [Sar1, Ala8]-angiotensin II, lowered arterial pressure. 3. Nevertheless, after inhibition of the renin-angiotensin system by these agents, the reduction in blood pressure induced by lower-body negative pressure became greater and the blood pressure recovery was impaired. 4. The findings suggest that angiotensin, at a blood concentration which has no direct effect on blood pressure, interacts with the sympathetic nervous system to maintain arterial blood pressure.
mesh_terms: D000806:Angiotensin-Converting Enzyme Inhibitors; D000809:Angiotensins / Q000502:physiology*; D000818:Animals; D001274:Atmospheric Pressure; D001794:Blood Pressure / Q000187:drug effects; D002415:Cats; D012018:Reflex / Q000502:physiology; D012083:Renin / Q000097:blood; D012504:Saralasin / Q000494:pharmacology; D013722:Teprotide / Q000494:pharmacology
chemical_list: D000806:Angiotensin-Converting Enzyme Inhibitors; D000809:Angiotensins; D013722:Teprotide; D012083:Renin; D012504:Saralasin