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Abstract #46431 Published in IGR 13-3
The Effect of Vasopressin on Choroidal Blood Flow, Intraocular Pressure and Orbital Venous Pressure in Rabbits
Bogner B; Tockner B; Runge C; Strohmaier C; Trost A; Branka M; Radner W; Kiel JW; Schroedel F; Reitsamer HAInvestigative Ophthalmology and Visual Science 2011;
PURPOSE: To investigate the effects of arginine-vasopressin (AVP) on intraocular pressure (IOP), orbital venous pressure (OVP) and choroidal blood flow (ChorBF) regulation in anesthetized rabbits. METHODS: Mean arterial pressure (MAP), IOP and OVP were measured by direct cannulation of the central ear artery, the vitreous and the orbital venous sinus, respectively. Laser Doppler flowmetry was used to record ChorBF. To change the perfusion pressure (PP) MAP was manipulated mechanically with occluders around the aorta and vena cava. In the first group of animals (n = 11) the dose-response relationship was measured. In the second group of animals (n = 8) pressure-flow relationships were determined at baseline and in response to intravenous application of a low (0.08 ng/kg/min) and a high (1.33 ng/kg/min) infusion rate of AVP. RESULTS: AVP caused a dose-dependent increase of MAP and choroidal vascular resistance (ChorR), while IOP, OVP, ChorBF and heart rate (HR) were decreased. In contrast to the high infusion rate, the low infusion rate of AVP had no effect on baseline ChorBF. However, the pressure-flow relationship was shifted downwards significantly by both infusion rates at PP below baseline. CONCLUSIONS: AVP reduces IOP and OVP significantly and is potent vasoconstrictor in the choroidal vascular bed. In the choroid the effect of AVP is not only dose-dependent, but also PP-dependent which is indicated by the reduced perfusion relative to control with low-dosed AVP at low PP.
Dept Ophthalmology and Optometry, SALK/Paracelsus Medical University, Salzburg, Austria.
Classification:
6.11 Bloodflow measurements (Part of: 6 Clinical examination methods)
6.1.3 Factors affecting IOP (Part of: 6 Clinical examination methods > 6.1 Intraocular pressure measurement; factors affecting IOP)
3.8 Pharmacology (Part of: 3 Laboratory methods)