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。

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.