Studies on the effects of angiotensin II on human chorionic plate arteries and their modification by a calcium antagonist, nitrendipine.

Publisher Website
Google Scholar
Abstract
1 Six‐point concentration‐response curves were initially established for the contractile effect of angiotensin II (AII), at final concentrations of 10(‐11) to 10(‐6) M, on helically‐cut strips of human chorionic plate arteries. The strips were then randomly allocated to one of four treatment groups: a control group and three treatment groups (n = 10 in each group) which were exposed to carrier or nitrendipine 10(‐11), 10(‐10) or 10(‐9) M final concentration respectively, before the establishment of second concentration‐response curves. 2 The initial responses of the tissues to AII were very similar in the four treatment groups with median EC50s ranging between 2.51 × 10(‐10) and 4.04 × 10(‐10) M (P greater than 0.8). The addition of nitrendipine was associated with significant (P less than 0.005) dose‐ related inhibition of AII‐induced contractions. The median EC50 of the control group during the second half of the experiment was 1.77 × 10(‐7) M, while that of the 10(‐11) M nitrendipine treatment group was 2.16 × 10(‐7) M. The EC50 for the other treatment groups could not be calculated from the curves due to the markedly blunted responses. 3 It is thus suggested that nitrendipine might be effective in vivo in the relief of vasospasm of the placental vascular system in pregnancy‐ induced hypertension.