Antunes Vagner R, Bonagamba Leni G H, Machado Benedito H
Department of Physiology, School of Medicine of Ribeirão Preto, University of São Paulo, 14049-900, Ribeirão Preto, SP, Brazil.
Brain Res. 2005 Jan 25;1032(1-2):85-93. doi: 10.1016/j.brainres.2004.10.048.
The nucleus tractus solitarii (NTS) is the site of integration of the peripheral chemoreceptor afferents in the brainstem. Previous studies from our laboratory have shown that microinjection of ATP into the intermediate NTS produced increases in arterial pressure and bradycardia. In the present study, we evaluated the hemodynamic and respiratory responses to microinjection of ATP into the intermediate and caudal commissural NTS. In the same group of rats the responses were compared with cardiorespiratory responses to chemoreflex activation (KCN, i.v.). The data show that microinjection of ATP into the intermediate NTS produced pressor and bradycardic responses similar to those observed in response to chemoreflex activation but apnoea instead of tachypnoea. Microinjection of ATP into caudal commissural NTS produced increase in arterial pressure and tachypnoea similar to the chemoreflex but a minor bradycardia. The data show that microinjection of ATP into different sub-regions of the NTS produces a diverse pattern of hemodynamic and respiratory responses and suggest the involvement of this purine in the neurotransmission of the cardiovascular reflex in the NTS.
孤束核（NTS）是脑干中整合外周化学感受器传入信号的部位。我们实验室之前的研究表明，向中间NTS微量注射ATP会导致动脉血压升高和心动过缓。在本研究中，我们评估了向中间和尾侧连合NTS微量注射ATP后的血流动力学和呼吸反应。在同一组大鼠中，将这些反应与化学反射激活（静脉注射KCN）后的心肺反应进行了比较。数据表明，向中间NTS微量注射ATP会产生与化学反射激活时观察到的类似的升压和心动过缓反应，但会出现呼吸暂停而非呼吸急促。向尾侧连合NTS微量注射ATP会导致动脉血压升高和呼吸急促，类似于化学反射，但心动过缓较轻。数据表明，向NTS的不同亚区域微量注射ATP会产生不同的血流动力学和呼吸反应模式，并提示这种嘌呤参与了NTS中心血管反射的神经传递。
