The cardiac-sympathetic contribution to blood pressure regulation

动脉压力感受器反射是控制动脉血压的最重要的反射之一。压力感受器反射通过控制心输出量和总外周阻力来缓冲生理应激期间发生的血压剧烈波动。因此，压力感受器反射的输出被认为由心率(心肺臂)和血管成分(交感臂)组成。在过去的5-8年里，在对有脊髓横断的啮齿动物进行综合生理学研究的过程中，我的实验室进行了许多关键的观察，表明可能也有心脏变力(即心脏-交感)臂对动脉的压力肌束起作用。 最近，我们发现当动脉压力感受器被卸载时，不仅外周血管阻力和心率增加，而且心脏变力功能也增加。尽管这样的反应是合乎逻辑的，但缺乏支持心脏正性肌力臂存在于动脉压力感受性反射控制血压的直接证据。此外，我们对神经解剖学通路的理解存在根本性的缺陷，神经解剖学通路在将这种反应从脑干传递到心脏和血管方面非常重要。 在接下来的5年里，我们将全面研究压力感受器反射的功能心脏变力臂的存在以及控制这种反应的潜在神经解剖通路，重点是脊柱节段控制。我们将具体评估压力感受器反射的机械和药物操作是否会导致相似的心脏和血管输出，以及测试控制机制是否因性别不同而受到化学感受器反射激活的影响。我们还将继续努力修改可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，其中我们还将把这种策略与末端器官功能联系起来。 建立和验证压力感受器反射的心脏正性肌力臂的存在，并确定潜在的神经解剖学控制，有望促进我们对压力感受器如何作用于维持动脉血压的基本理解。这些研究涵盖了许多不同的领域，并为HQP提供了一个很好的培训环境，他们将接受手术准备和高级数据处理的所有方面的培训。

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.