Barnes K L, Knowles W D, Ferrario C M
Department of Brain and Vascular Research, Cleveland Clinic Foundation, OH 44195.
Brain Res Bull. 1990 Feb;24(2):275-80. doi: 10.1016/0361-9230(90)90215-l.
Our group showed previously that the heptapeptide angiotensin (1-7) [Ang-(1-7)] is a bioactive product of the renin-angiotensin system, and produces dose-dependent cardiovascular effects similar to those evoked by Ang II when microinjected into the nucleus tractus solitarii (nTS) of the rat. The effects of Ang II were compared with those of Ang-(1-7) on single neuron activity recorded from the medial nTS or dorsal motor nucleus of the vagus (dmnX) in perifused horizontal slices of the canine dorsomedial medulla. Ang II excited 48% of 31 medial nTS neurons, but only activated 14% of 22 dmnX cells. Ang-(1-7) also excited half of the medial nTS cells and 14% of the dmnXl neurons. Although most medial nTS neurons excited by Ang II were also activated by Ang-(1-7), two cells were excited by Ang II but not by Ang-(1-7), and one cell was excited by Ang-(1-7) but not by Ang II. Because Ang-(1-7) lacks direct vasoconstrictor effects, neurons in the dorsomedial medulla may have different receptor characteristics than peripheral tissues. The observation of a few medial nTS neurons excited by only one Ang peptide suggests that there may be a separate Ang-(1-7) receptor that participates in the physiological effects of Ang peptides mediated by the brain.
我们小组先前表明，七肽血管紧张素（1-7）[Ang-（1-7）]是肾素-血管紧张素系统的一种生物活性产物，当微量注射到大鼠孤束核（nTS）时，会产生与Ang II引起的剂量依赖性心血管效应相似的效应。在犬背内侧延髓的灌流水平切片中，比较了Ang II和Ang-（1-7）对从内侧nTS或迷走神经背运动核（dmnX）记录的单个神经元活动的影响。Ang II兴奋了31个内侧nTS神经元中的48%，但仅激活了22个dmnX细胞中的14%。Ang-（1-7）也兴奋了一半的内侧nTS细胞和14%的dmnXl神经元。尽管大多数被Ang II兴奋的内侧nTS神经元也被Ang-（1-7）激活，但有两个细胞被Ang II兴奋而未被Ang-（1-7）兴奋，还有一个细胞被Ang-（1-7）兴奋而未被Ang II兴奋。由于Ang-（1-7）缺乏直接的血管收缩作用，背内侧延髓中的神经元可能具有与外周组织不同的受体特征。少数仅被一种Ang肽兴奋的内侧nTS神经元的观察结果表明，可能存在一种单独的Ang-（1-7）受体，它参与由大脑介导的Ang肽的生理效应。
