Department of Physiological Sciences, Federal University of Espírito Santo, Vitória, ES, Brazil.
Ecotoxicol Environ Saf. 2012 Jun;80:203-7. doi: 10.1016/j.ecoenv.2012.03.001. Epub 2012 Mar 29.
Poisoning by organophosphorus insecticides is often accompanied by cardiac complications which may be serious and even fatal. However, the effects of these compounds on the cardiovascular mechanisms involved in blood pressure regulation are not known. The aim of this study was to evaluate the effects of a sublethal dose (8 mg/kg, i.p.) of the organophosphorus methamidophos on chemoreceptor (CR) and Bezold-Jarisch (BJR) cardiovascular reflexes. Male Wistar rats were treated with single intraperitoneal injections of methamidophos in saline (n=23) or saline (0.9 percent, n=20) and underwent catheterization of femoral artery and vein one day after the injections. Cardiovascular recordings were performed 24h after the catheterization procedure. Plasma cholinesterase (ChE) activity was measured 24h after similar treatments in separate groups (n=10/group). The bradycardic component of CR and BJR was significantly attenuated in animals treated with methamidophos. The ChE activity was 80 percent reduced in the methamidophos-treated animals. Methamidophos impairment of the bradycardic component of two important cardiovascular reflexes may contribute to the cardiovascular toxicity associated with acute organophosphorus insecticides exposure.
有机磷杀虫剂中毒常伴有心脏并发症，这些并发症可能很严重，甚至是致命的。然而，这些化合物对参与血压调节的心血管机制的影响尚不清楚。本研究旨在评估亚致死剂量（8mg/kg，ip）的有机磷甲胺磷对化学感受器（CR）和贝兹old-Jarisch（BJR）心血管反射的影响。雄性 Wistar 大鼠单次腹腔注射甲胺磷生理盐水（n=23）或生理盐水（0.9%，n=20），注射后 1 天进行股动脉和股静脉导管插入术。导管插入术后 24 小时进行心血管记录。在类似处理的单独组（n=10/组）中，24 小时后测量血浆胆碱酯酶（ChE）活性。用甲胺磷处理的动物的 CR 和 BJR 的心动过缓成分明显减弱。甲胺磷处理组的 ChE 活性降低了 80%。甲胺磷对两种重要心血管反射的心动过缓成分的损害可能导致与急性有机磷杀虫剂暴露相关的心血管毒性。
