Trzeciakowski Jerome, Chilian William M
Department of Systems Biology and Translational Medicine, Texas A&M Health Science Center College of Medicine, College Station, TX, USA.
Med Biol Eng Comput. 2008 May;46(5):433-42. doi: 10.1007/s11517-008-0329-8.
The regulation of the coronary circulation is a complex paradigm in which many inputs that influence vasomotor tone have to be integrated to provide the coronary vasomotor adjustments to cardiac metabolism and to perfusion pressure. We hypothesized that the integration of many disparate signals that influence membrane potential of smooth muscle cells, calcium sensitivity of contractile filaments, receptor trafficking result in complex non-linear characteristics of coronary vasomotion. To test this hypothesis, we measured an index of vasomotion, flowmotion, the periodic fluctuations of flow that reflect dynamic changes in resistances in the microcirculation. Flowmotion was continuously measured in periods ranging from 15 to 40 min under baseline conditions, during antagonism of NO synthesis, and during combined purinergic and NOS antagonism in the beating heart of anesthetized open-chest dogs. Flowmotion was measured in arterioles ranging from 80 to 135 microm in diameter. The signals from the flowmotion measurements were used to derive quantitative indices of non-linear behavior: power spectra, chaotic attractors, correlation dimensions, and the sum of the Lyapunov exponents (Kolmogorov-Sinai entropy), which reflects the total chaos and unpredictability of flowmotion. Under basal conditions, the coronary circulation demonstrated chaotic non-linear behavior with a power spectra showing three principal frequencies in flowmotion. Blockade of nitric oxide synthase or antagonism of purinergic receptors did not affect the correlation dimensions, but significantly increased the Kolmogorov-Sinai entropy, altered the power spectra of flowmotion, and changed the nature of the chaotic attractor. These changes are consistent with the view that certain endogenous controls, nitric oxide and various purines (AMP, ADP, ATP, adenosine) make the coronary circulation more predictable, and that blockade of these controls makes the control of flow less predictable and more chaotic.
冠状动脉循环的调节是一个复杂的范例，其中许多影响血管舒缩张力的输入因素必须整合起来，以实现冠状动脉血管舒缩对心脏代谢和灌注压力的调节。我们假设，许多影响平滑肌细胞膜电位、收缩细丝钙敏感性、受体转运的不同信号的整合，导致了冠状动脉运动的复杂非线性特征。为了验证这一假设，我们测量了血管运动指数——血流运动，即反映微循环中阻力动态变化的血流周期性波动。在基础条件下、一氧化氮合成受拮抗期间以及嘌呤能和一氧化氮合酶联合拮抗期间，在麻醉开胸犬的跳动心脏中，连续15至40分钟测量血流运动。在直径为80至135微米的小动脉中测量血流运动。血流运动测量得到的信号用于推导非线性行为的定量指标：功率谱、混沌吸引子、关联维数以及李雅普诺夫指数之和（柯尔莫哥洛夫-西奈熵），后者反映了血流运动的总体混沌性和不可预测性。在基础条件下，冠状动脉循环表现出混沌非线性行为，功率谱显示血流运动有三个主要频率。一氧化氮合酶的阻断或嘌呤能受体的拮抗并不影响关联维数，但显著增加了柯尔莫哥洛夫-西奈熵，改变了血流运动的功率谱，并改变了混沌吸引子的性质。这些变化与以下观点一致，即某些内源性控制因素，一氧化氮和各种嘌呤（AMP、ADP、ATP、腺苷）使冠状动脉循环更具可预测性，而对这些控制因素的阻断使血流控制更不可预测且更混沌。
