title: Role of Glial Cells in Regulating Retinal Blood Flow During Flicker-Induced Hyperemia in Cats.
abstract: OBJECTIVE
  To investigate how glial cells participate in retinal circulation during flicker stimulation in cats.
  
  
  METHODS
  Using laser Doppler velocimetry, we measured the vessel diameter and blood velocity simultaneously and calculated the retinal blood flow (RBF) in feline first-order retinal arterioles. Twenty-four hours after intravitreal injections of L-2-aminoadipic acid (LAA), a gliotoxic compound, and the solvent of 0.01 N hydrochloric acid as a control, we examined the changes in RBF in response to 16-Hz flicker stimulation for 3 minutes. We also measured the changes in RBF 2 hours after intravitreal injection of Nω-propyl-L-arginine (L-NPA), a selective neuronal nitric oxide synthase inhibitor, in LAA-treated eyes. To evaluate the effects of LAA on retinal neuronal function, ERGs were monitored. Immunohistochemical examinations were performed.
  
  
  RESULTS
  In LAA-treated eyes, histologic changes selectively occurred in retinal glial cells. There were no significant reductions in amplitude or elongation of implicit time in ERG after LAA injections compared with controls. In control eyes, the RBF gradually increased and reached the maximal level (53.5% ± 2.5% increase from baseline) after 2 to 3 minutes of flicker stimulation. In LAA-treated eyes, the increases in RBF during flicker stimulation were attenuated significantly compared with controls. In LAA-treated eyes 2 hours after injection of L-NPA, flicker-evoked increases in RBF decreased significantly compared with LAA-treated eyes.
  
  
  CONCLUSIONS
  The current results suggested that increases in RBF in response to flicker stimulation were regulated partly by retinal glial cells.
authors.forename: Youngseok
authors.initials: Y
authors.lastname: Song
authors.forename: Taiji
authors.initials: T
authors.lastname: Nagaoka
authors.forename: Takafumi
authors.initials: T
authors.lastname: Yoshioka
authors.forename: Seigo
authors.initials: S
authors.lastname: Nakabayashi
authors.forename: Tomofumi
authors.initials: T
authors.lastname: Tani
authors.forename: Akitoshi
authors.initials: A
authors.lastname: Yoshida
mesh_terms: D000818:Animals; D002415:Cats; D004195:Disease Models, Animal; D004596:Electroretinography; D005260:Female; D006940:Hyperemia / Q000473:pathology / Q000503:physiopathology*; D007150:Immunohistochemistry; D017078:Laser-Doppler Flowmetry; D008297:Male; D009457:Neuroglia / Q000473:pathology*; D010775:Photic Stimulation; D012039:Regional Blood Flow / Q000502:physiology*; D012171:Retinal Vessels / Q000503:physiopathology*