Y Ogata1, T Kaneko, N Kayama, S Ueno. 1. Department of Ophthalmology, St. Marianna University School of Medicine, Kawasaki, Japan.
Abstract
PURPOSE: The effects of nilvadipine on retinal blood flow and systemic circulation were studied by the hydrogen clearance method. MATERIALS AND METHODS: The subjects were 10 male beagles. Under general anesthesia, nilvadipine (32 micrograms/ml/kg), dissolved in polyethylene glycols was injected into the stomach of 5 beagles, and only polyethylene glycols was injected into the stomach of the other 5 beagles as controls. Retinal tissue blood flow, heart rate, arterial blood pressure, pulmonary arterial pressure, central vein pressure, cardiac output, and systemic vessel resistance were measured over time and compared between the two groups. RESULTS: Retinal tissue blood flow showed significant increase only in the Nilvadipine group (max 29.2%). No marked changes were observed in the systemic circulation in either group. The time to maximum blood concentration of Nilvadipine was 120 min, and the maximum blood concentration was 1.27 ng/ml. CONCLUSION: Nilvadipine may directly and selectively increase retinal tissue blood flow, while having only minimal effect on systemic circulation including arterial blood pressure.
PURPOSE: The effects of nilvadipine on retinal blood flow and systemic circulation were studied by the hydrogen clearance method. MATERIALS AND METHODS: The subjects were 10 male beagles. Under general anesthesia, nilvadipine (32 micrograms/ml/kg), dissolved in polyethylene glycols was injected into the stomach of 5 beagles, and only polyethylene glycols was injected into the stomach of the other 5 beagles as controls. Retinal tissue blood flow, heart rate, arterial blood pressure, pulmonary arterial pressure, central vein pressure, cardiac output, and systemic vessel resistance were measured over time and compared between the two groups. RESULTS: Retinal tissue blood flow showed significant increase only in the Nilvadipine group (max 29.2%). No marked changes were observed in the systemic circulation in either group. The time to maximum blood concentration of Nilvadipine was 120 min, and the maximum blood concentration was 1.27 ng/ml. CONCLUSION:Nilvadipine may directly and selectively increase retinal tissue blood flow, while having only minimal effect on systemic circulation including arterial blood pressure.