Acute responses to arterial pressure and plasma renin activity to converting enzyme inhibition (SQ 20,881) in serially studied dogs with neonatally-induced coarctation hypertension
Bagby, S.P.
Hypertension 4(1): 146-154
1982
ISSN/ISBN: 0194-911X PMID: 6174444 Document Number: 192213
In 6 inbred dogs with neonatally induced coarctation hypertension, and in 7 littermate controls, acute responses of proximal arterial pressure and plasma renin activity (PRA) to converting enzyme inhibitor (CEI; SQ 20881 , 0.5 mg/kg i.v.) were serially examined. Studies were performed at 2, 6 and 12 mo. post-aortic banding under Na-replete and -deplete conditions. Both in normotensive controls and in coarcted dogs, depressor responses (pre- minus post-CEI values) were positively correlated, not only with initial (pre-CEI) PRA, but also independently with initial blood pressure. Although absolute depressor responses in coarcted dogs exceeded those of the control group, there were no significant group differences when, by analysis of covariance, depressor responses were adjusted for the physiologic influence of initial pressure. Similarly, depressor responses expressed as a percent of initial pressure were comparable in coarcted and control groups. Initial PRA and PRA response to CEI in coarcted dogs were also comparable to control dogs; the PRA response correlated with initial PRA in both groups. CEI did not significantly diminish the magnitude of blood-pressure difference between coarcted and control dogs. In neonatally-induced coarctation hypertension, under both Na-replete and -deplete conditions, acute depressor and PRA responses to CEI are modulated by the same factors that influence responses of normotensive controls; larger absolute depressor responses to CEI appear to be a physiologic function of higher initial pressure; and blood pressure excess over littermate controls is largely sustained by CEI-resistant factors, potentially including the known volume excess in coarcted dogs.