Postocclusive reactive hyperemia occurs in the rat retinal circulation but not in the choroid.

摘要: PURPOSE We tested the hypothesis that retinal blood flow has a postocclusive reactive hyperemia response modulated by occlusion duration and metabolic activity, choroidal does not. METHODS Anesthetized paralyzed rats (n = 34) were studied. Retinal was measured laser speckle imaging Doppler flowmetry, respectively. Blood oxygenation level-dependent functional magnetic resonance (BOLD fMRI) used to measure changes in relative of circulations. Transient carotid elicited with hydraulic occluder on common artery. Several durations during dark, constant light, flicker light conditions modulate demand. The magnitude quantified integrating area above baseline for 3 minutes after release occlusion. RESULTS Systemic arterial pressure (108.2 ± 1.4 mm Hg) unaffected occlusions, similar among animals conditions. had hyperemia, but did not (e.g., 14 2%.sec versus 0.5 4%. sec 60-second occlusion). increased as nonlinear function reached plateau at < 60 second. altered different lighting 15 seconds. BOLD fMRI results laser-based measurements. CONCLUSIONS indicate local control negligible role regulation only partially accounts behavior circulation.