Real-Time Evaluation of Regional Arterial Stiffening, Resistance, and Ocular Circulation During Systemic Administration of Adrenaline in White Rabbits.

Abstract

PurposeTo 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.MethodsSix 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.ResultsThe MBR-RV and MBR-CH values were dose-dependently increased by the adrenaline in parallel with increased BP. At the load of 100 ng/kg adrenaline, the ΔMBR-RV and ΔMBR-CH showed positive correlations with the variation rate in mean arterial blood pressure. Also, the variation rate in carotid vascular resistance and the Δfa-PWV and Δhf-PWV were significantly positively correlated with both the ΔMBR-RV and ΔMBR-CH. At the 300-ng/kg phase, the correlations between the Δha-PWV and both ΔMBR-RV and ΔMBR-CH were canceled; instead, the Δhf-PWV showed a significant negative correlation with the ΔMBR-RV and ΔMBR-CH. At the 1000-ng/kg phase, Δha-PWV again showed significant positive correlations with the ΔMBR-RV and ΔMBR-CH.ConclusionsThese 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 RelevanceA real-time evaluation system of systemic regional arterial function and ocular microcirculation in rabbits was developed.