Frequency analysis instrumentation for sinus wall and baroreceptor responses

Blood pressure regulation involves feedback signals from baroreceptors detecting wall strain of arterial sinuses. A research goal is identification of wall viscoelastic properties and associations between elements and baroreceptors. This report presents development of computer-based procedures for control of pressure inputs and recording responses of an in situ carotid sinus. Features include a hydraulic system to generate swept-frequency sinusoidal pressure inputs (0.2 to 200 Hz); measurements of: (i) sinus wall area and vectors of strain using a fiber optic sensor system, (ii) intrasinus pressure using solid state probes, (iii) baroreceptor fiber activity using a unipolar electrode and (iv) algorithms for data archival, frequency domain analysis and transfer function determinations. Data analysis will focus on estimates of wall properties of elasticity (K), viscosity (C), natural frequency (omega w), damping ratio (zeta w), reactive mass (Mw) and relationships to similar properties at tissue-baroreceptor junctions. Computer-based procedures are exemplified with data detailing mechanical properties of the hydraulic system; which is an important prerequisite to analysis of sinus viscoelastic properties.