A mathematical model of the afferent stage of the mammalian baroreceptor reflex

[摘要] The purpose of this research effort is to develop a mathematical model of the afferent portion mammalian arterial baroreceptor reflex. The entire model is comprised of a small network of Hodgkin-Huxley (HH) type membrane models representing the minimum number of anatomical structures (i.e. neurons and afferent terminations) participating in the transduction, transmission and the initial processing stage for arterial pressure information within the medullary cardiovascular control centers. The structures represented are: arterial wall and baroreceptor terminal endings (BR), which encode arterial pressure into frequency modulated action potential trains; the synaptic connection (SYN) between sensory afferent terminations and medial nucleus tractus solitorius neurons (mNTS) which are the first brainstem neurons participating in the arterial baroreflex. Realistic membrane models of the peripheral and central terminations (i.e. BR and SYN) was made possible through the initial development of a comprehensive mathematical model of isolated nodose sensory neurons. Individually, the excitable membrane have all been modeled using HH-type formalisms which have been modeled using an iterative process of electrophysiological recordings, nonlinear parameter estimation, phase-plane analysis and computer simulation. Each component model provides good numerical fits to quantitative whole-cell voltage clamp and action potential data (i.e. rat) recorded both by myself and our scientific collaborators. Each membrane model, with the exception of the BR, is coupled to a lumped fluid compartment model that describes Ca$sp{2+}$ ion concentration dynamics within the intracellular media in addition to buffering via a calmodulin-type buffer. The complete model attempts to describe the essential electrophysiological characteristics of this primary input stage of the baroreflex system in the rat.

[发布机构] Rice University

[效力级别] Electronics