Real-Time Evaluation of Regional Arterial Stiffening, Resistance, and Ocular Circulation During Systemic Administration of Adrenaline in White Rabbits (vol 10, 11, 2021)

Purpose: To evaluate continuous variations of ocular microcirculation by laser speckle flowgraphy and those of regional stiffening by pulse wave velocity (PWV) and vascular resistance under systemic adrenaline administration in rabbits.Methods: Six 16-week-old male rabbits were evaluated. The mean blur rates in the retinal vessel (MBR-RV) and choroid (MBR-CH) were measured. We assessed blood pressure (BP), femoral and carotid vascular resistance, and the heart-ankle (ha)-PWV, heart-femoral (hf)-PWV, and femoral-ankle (fa)-PWV. Adrenaline (100, 300, and 1000 ng/kg) was intravenously administered over a 10-minute period during which the parameters were measured simultaneously every 2 minutes.Results: The MBR-RV and MBR-CH values were dose-dependently increased by the adrenaline in parallel with increased BR. At the load of 100 ng/kg adrenaline, the Delta MBR-RV and Delta MBR-CH showed positive correlations with the variation rate in mean arterial blood pressure. Also, the variation rate in carotid vascular resistance and the Delta fa-PWV and Delta hf-PWV were significantly positively correlated with both the Delta MBR-RV and Delta MBR-CH. At the 300-ng/kg phase, the correlations between the Delta ha-PWV and both Delta MBR-RV and Delta MBR-CH were canceled; instead, the Delta hf-PWV showed a significant negative correlation with the AMBR-RV and AMBR-CH. At the 1000-ng/kg phase, Delta ha-PWV again showed significant positive correlations with the Delta MBR-RV and Delta MBR-CH.Conclusions: These results indicate the possibility that under a systemic administration of adrenaline in rabbits, not only the BP value but also the vascular resistance and arterial function are related to the variation in ocular microcirculation.Translational Relevance: A real-time evaluation system of systemic regional arterial function and ocular microcirculation in rabbits was developed.