Takizawa T, Oda T, Arishima K, Yamamoto M, Masaoka T, Somiya H, Akahori F, Shiota K
Department of Developmental Biotechnology, Azabu University, School of Veterinary Medicine, Kanagawa, Japan.
J Toxicol Sci. 1994 Aug;19(3):171-4. doi: 10.2131/jts.19.3_171.
Newborn rats delivered by caesarean section were given subcutaneously verapamil hydrochloride (VER), a Ca-channel blocker, (1) immediately or (2) 180 min after delivery. The diameter of the ductus arteriosus (DA) of the newborn pups was calibrated at 30, 60 and 90 min after the VER-administration. (1) The DA calibers of the pups given 0.1, 1.0 mg/kg VER immediately after delivery remained significantly larger than those of control pups in a dose-dependent manner for 30 min after treatment. In the 1 mg/kg group, the enlargement of the DA was prolonged until 90 min after treatment. (2) In untreated pups, the DA completely closed by 180 min after caesarean delivery. The closed DA was not affected after 1 mg/kg VER was given at 3 hours after delivery. It was concluded that, VER inhibits the spontaneous constriction of the DA, suggesting that the increase of intracellular Ca2+ concentration may play an important role on the spontaneous closure of the DA in newborn rats.
通过剖腹产分娩的新生大鼠在（1）分娩后立即或（2）分娩后180分钟皮下注射钙通道阻滞剂盐酸维拉帕米（VER）。在给予VER后30、60和90分钟测量新生幼崽动脉导管（DA）的直径。（1）分娩后立即给予0.1、1.0mg/kg VER的幼崽，其DA管径在治疗后30分钟内以剂量依赖方式显著大于对照幼崽。在1mg/kg组中，DA的扩大持续到治疗后90分钟。（2）未治疗的幼崽在剖腹产分娩后180分钟时DA完全关闭。在分娩后3小时给予1mg/kg VER后，已关闭的DA不受影响。得出的结论是，VER抑制DA的自发收缩，表明细胞内Ca2+浓度的增加可能在新生大鼠DA的自发关闭中起重要作用。
