Arterial Baroreflex Control of Blood Pressure (Exercise)

动脉压力反射控制血压（运动）

• 批准号: 6616432
• 负责人: PETER Bernard RAVEN
• 金额: $ 35.5万
• 依托单位: UNIVERSITY OF NORTH TEXAS HLTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 1996
• 资助国家: 美国
• 起止时间: 1996-06-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6616432
• 关键词: aerobic exercise; baroreceptors; baroreflex; blood chemistry; blood pressure; blood volume; cardiac output; cardiovascular pharmacology; carotid body; clinical research; heart rate; human subject; metformin; muscle metabolism; noninsulin dependent diabetes mellitus; physical fitness; potassium channel; vascular smooth muscle nervous control; vasoconstriction

DESCRIPTION (provided by applicant): A number of investigations have demonstrated that arterial baroreflex (CBR) control of blood pressure has a primary role in providing the necessary regulation of the sympathetic neural outflow to active and inactive tissue beds associated with dynamic exercise. In addition, we have documented a reduced vasoconstrictive response to hypotension of the highly trained endurance athlete despite an augmented CBR mediated increase in MSNA. A growing body of evidence suggests that the regulatory role of sympathetic neural outflow to the vasculature is modulated by metabolic by-products released within the active tissue and involve mechanisms of functional sympatholysis. A suggested mechanism of functional sympatholysis is that contraction induced metabolites within the active muscle open ATP-sensitive potassium (KATP) channels and thereby partially inhibit sympathetic vasoconstriction. However, it has recently been demonstrated that the CBR mediated vasoconstriction within the active muscle provides the greatest reflex vasoconstrictor response to hypotension during exercise. Therefore, we hypothesize that the CBR has a fundamental role in the control of MSNA and skeletal muscle vasculature at rest and during exercise. Furthermore, we contend that the CBR regulation of vasomotor function in exercising muscle is altered by local metabolic by-products and their interaction with other vasoactive substances and the KATP channels of the vascular smooth muscle within the active tissue. In addition, these mechanisms of CBR control of the vasculature are modulated by endurance exercise training. To address these hypotheses: Comparisons of carotid baroreflex function curves of blood pressure (BP), MSNA and leg vascular conductance (LVC) will be made between rest, the non-exercising leg (NEL) and the exercising leg (EL) using the classic one-legged exercise protocol performed by humans. Carotid baroreflex function will be assessed using our well established modeling technique. Comparisons of CBR function curves of BP, MSNA and LVC will be made at rest, in the NEL and the EL (except MSNA) between average fit, high fit endurance trained athletes and NIDDM patients treated with glibenclamide and NIDDM patients treated with Metformin. We anticipate that the findings obtained from this project will provide a comprehensive understanding of the fundamental mechanisms involved in the regulation of arterial blood pressure by the arterial baroreflex and its influence on the regulation of vasomotion in active muscle tissue and inactive muscular tissue in matching blood flow to oxygen demand during exercise in humans. These findings will have implications for the care of patients suffering from non-insulin dependent diabetes mellitus (NIDDM), hypertension and cardiac failure.

描述(申请人提供)：许多研究表明，动脉压力感受性反射(CBR)对血压的控制在提供必要的交感神经外流到与动态运动相关的活跃和非活跃组织床方面具有主要作用。此外，我们还发现，尽管CBR介导的MSNA增加，但训练有素的耐力运动员对低血压的血管收缩反应减弱。越来越多的证据表明，交感神经外流对血管系统的调节作用是由活跃组织内释放的代谢副产物调节的，涉及功能性交感神经溶解的机制。功能性交感神经溶解的一种机制是收缩引起活跃肌肉内的代谢物开放ATP敏感钾(KATP)通道，从而部分抑制交感神经血管收缩。然而，最近的研究表明，CBR介导的活动肌肉内的血管收缩反应是运动中对低血压反应最大的反射性血管收缩反应。因此，我们假设CBR在静息和运动中对MSNA和骨骼肌血管系统的控制具有基础性作用。此外，我们认为，CBR对运动肌肉血管运动功能的调节受到局部代谢副产物及其与其他血管活性物质和活性组织内血管平滑肌KATP通道相互作用的影响。此外，CBR对血管系统的这些控制机制也受到耐力运动训练的调节。为了解决这些假设：我们将使用经典的单腿锻炼方案，比较静息、非锻炼腿(NEL)和锻炼腿(EL)之间的血压(BP)、MSNA和腿部血管电导(LVC)的颈动脉压力感受器反射功能曲线。颈动脉压力感受器反射功能将使用我们成熟的建模技术进行评估。比较中等体能、高体能耐力训练运动员、格列本脲治疗的NIDDM患者和二甲双胍治疗的NIDDM患者在安静时、NEL和EL(除MSNA外)的BP、MSNA和LVC的CBR功能曲线。我们期望这一项目的发现将全面了解动脉压力感受性反射调节动脉血压的基本机制，以及它对人体运动中活跃肌肉组织和非活跃肌肉组织在匹配血流量和需氧量方面的血管运动调节的影响。这些发现将对患有非胰岛素依赖型糖尿病(NIDDM)、高血压和心力衰竭的患者的护理具有指导意义。