Endothelial vasoactive influence simulated by exponential feedback

We hypothesized that results from rabbit carotid sinus wall and baroreceptors could be simulated using exponential feedback in a viscoelastic model. Wall and baroreceptor were each modeled by second order differential equations. Coefficients for viscosity, elasticity and feedback were estimated from experimental data. Feedback of model wall distension (y1) on viscosity (C) was expressed by the transfer function: C/y1 = RW/(s tau W + 1). With gain (RW) = 52.5E6 N(s)/m2 and tau W = 34 sec, this feedback resulted in simulation of wall response for sinuses with intact endothelium. Model receptor required no (or negative gain) feedback to simulate baroreceptors.