title: Intravenous nicardipine in cats increases optic nerve head but not retinal blood flow.
abstract: The effect of intravenously injected nicardipine on retinal and optic nerve head (ONH) blood flow was studied in 27 cats using laser Doppler velocimetry and flowmetry, respectively. A dose of 20 micrograms/kg of nicardipine had little effect on retinal blood flow. A dose of 100 micrograms/kg, however, produced a significant transient decrease in flow. By contrast, both doses produced a significant increase in ONH blood flow despite a significant decrease of the mean arterial blood pressure. Measurements of the partial pressure of oxygen (PO2) with an oxygen-sensitive microelectrode, whose tip was placed in the vitreous just in front of the optic disc, showed a significant increase in the PO2 that paralleled the increase in ONH blood flow. These results demonstrate, for the first time to the authors' knowledge, a pharmacologically induced increase in ONH blood flow and suggest that nicardipine could have a beneficial effect on ONH tissue.
authors.affiliation: Department of Ophthalmology, University of Pennsylvania, Philadelphia.
authors.forename: S
authors.initials: S
authors.lastname: Harino
authors.forename: C E
authors.initials: CE
authors.lastname: Riva
authors.forename: B L
authors.initials: BL
authors.lastname: Petrig
mesh_terms: D000818:Animals; D001783:Blood Flow Velocity / Q000187:drug effects*; D002415:Cats; D006439:Hemodynamics / Q000187:drug effects; D007275:Injections, Intravenous; D008839:Microelectrodes; D009529:Nicardipine / Q000494:pharmacology*; D009898:Optic Disk / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000502:physiology; D010101:Oxygen Consumption; D012171:Retinal Vessels / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000502:physiology; D014463:Ultrasonography
chemical_list: D009529:Nicardipine