The cardiac-sympathetic contribution to blood pressure regulation

动脉压力反射可以说是控制动脉血压的最重要的反射之一。压力反射通过控制心输出量和总外周阻力来缓冲生理应激时发生的急性血压波动。因此，压力反射的“输出”被认为是由心率（心肺臂）和血管成分（交感臂）组成的。在过去的5-8年里，在对脊椎横断的啮齿动物进行综合生理学研究时，我的实验室进行了一些关键的观察，这些观察表明，动脉血压弯曲可能也存在心脏肌力（即心脏交感神经）臂。最近，我们发现当动脉压力感受器被卸下时，不仅外周血管阻力和心率增加，而且心脏的肌力功能也增加。虽然这样的反应是合乎逻辑的，但缺乏直接证据支持心脏-肌力臂对动脉压力反射控制血压的存在。此外，我们对从脑干传导到心脏和血管的神经解剖学通路的理解存在根本缺陷。在接下来的5年里，我们将全面研究功能性心脏-肌力臂对压力反射的影响，以及控制这种反应的潜在神经解剖学途径，特别强调脊柱节段性控制。我们将特别评估压力反射的机械和药理学操作是否会导致相似的心脏和血管输出，并测试控制机制是否因性别而异，是否受到化学反射激活的影响。我们还将继续努力修改用于人类交感神经记录的后处理软件，以研究和解码啮齿动物的交感神经传递，其中我们将额外将此类策略与终器官功能联系起来。建立和验证一个功能性的心脏-肌力臂对压力反射的影响，并确定潜在的神经解剖学控制，有望促进我们对压力反射如何维持动脉血压的基本理解。这些研究跨越了多个不同的领域，为HQP提供了一个良好的培训环境，他们将在手术准备和高级数据处理的各个方面接受培训。

The arterial baroreflex is arguably one of the most important reflexes in the control of arterial blood pressure (BP). The baroreflex buffers acute fluctuations in BP that occur during physiological stressors by controlling cardiac output and total peripheral resistance. Thus the `output' from the baroreflex is considered to consist of a heart rate (cardiopulmonary arm) and vascular component (sympathetic arm). In conducting integrative physiological studies in rodents with spinal transection over the last 5-8 years, my lab has made a number of key observations that imply there may also be a cardiac inotropic (i.e., cardiac-sympathetic) arm to the arterial baroroeflex. Recently, we have found that when the arterial baroreceptors are unloaded there is not only an increase in peripheral vascular resistance and heart rate but there is also an increase in cardiac inotropic function. Though such a response is logical, direct evidence supporting the presence of a cardiac-inotropic arm to the arterial baroreflex control of blood pressure is lacking. Moreover, fundamental shortcomings exist in our understanding of the neuroanatomical pathways that are important in transducing this response from the brainstem to the heart and blood vessels. Over the next 5 years we will comprehensively study the presence of a functional cardiac-inotropic arm to the baroreflex along with the underlying neuroanatomic pathways that control this response, with a particular emphasis on spinal segmental control. We will specifically assess whether mechanical and pharmacological manipulation of the baroreflex results in similar cardiac and vascular outputs, as well as testing whether control mechanisms differ by sex and are impacted by activation of the chemoreflex. We will also continue our ongoing efforts to modify the post-processing software available for human sympathetic recordings to study and decode sympathetic neural transmission in rodents, wherein we will additionally relate such strategies to end-organ function. Establishing and validating the presence of a functional cardiac-inotropic arm to the baroreflex and determining the underlying neuroanatomical control is expected to advance our basic understanding of how the baroreflex functions to maintain arterial blood pressure. The studies proposed span a number of diverse fields and provide an excellent training environment for HQP who will be trained in all aspects of the surgical preparation and advanced data processing.