Gard Paul R, Daw Pauline, Mashhour Zhila Sayyad, Tran Paula
School of Pharmacy & Biomolecular Sciences, University of Brighton, Brighton, UK.
J Renin Angiotensin Aldosterone Syst. 2007 Sep;8(3):133-8. doi: 10.3317/jraas.2007.016.
Angiotensin (Ang) IV enhances learning and memory in rats but there are strain differences in its effects in mice. Oxytocin (OT) also influences learning and memory in rats and mice and, in the light of the proposed effects of Ang IV on oxytocinase, the hypothesis that the effects of Ang IV on cognition in mice involve OT was tested.
The effects of Ang IV and OT, alone and combined, were determined in rat isolated uterine smooth muscle and in object recognition and forced swim tests in BKW mice.
Ang potentiated the contractile effects of OT in the uterus. Neither peptide had any effect on object recognition nor locomotor activity. Ang IV had no effect in the forced swim test but abolished the effects of OT.
Ang IV influences the actions of OT in vitro and in vivo, possibly by inhibition of oxytocinase, but the lack of effect of Ang IV on object recognition in BKW mice is unlikely to be a consequence of a deficiency endogenous OT. Unlike OT, Ang IV alone has no effect on learned helplessness in the forced swim test, an effect often used to predict potential antidepressant efficacy in humans.
血管紧张素（Ang）IV可增强大鼠的学习和记忆能力，但在小鼠中其作用存在品系差异。催产素（OT）也会影响大鼠和小鼠的学习和记忆，鉴于Ang IV对催产素酶的假定作用，对Ang IV对小鼠认知的影响涉及OT这一假说进行了检验。
在大鼠离体子宫平滑肌以及BKW小鼠的物体识别和强迫游泳试验中，分别测定了单独使用及联合使用Ang IV和OT的效果。
Ang增强了OT在子宫中的收缩作用。两种肽对物体识别和运动活性均无影响。Ang IV在强迫游泳试验中无作用，但消除了OT的作用。
Ang IV在体外和体内影响OT的作用，可能是通过抑制催产素酶，但Ang IV对BKW小鼠物体识别无作用不太可能是内源性OT缺乏的结果。与OT不同，单独使用Ang IV对强迫游泳试验中的习得性无助无作用，而习得性无助常用于预测对人类的潜在抗抑郁疗效。
