Role of Neuronal Nitric Oxide Synthase in Regulating Retinal Blood Flow During Flicker-Induced Hyperemia in Cats

Yoshioka, Takafumi; Nagaoka, Taiji; Song, Youngseok; Yokota, Harumasa; Tani, Tomofumi; Yoshida, Akitoshi

doi:10.1167/iovs.14-15854

Cited by 21 publications

(26 citation statements)

References 36 publications

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“…36 Recently, we reported that L-NPA (5 mM), a selective nNOS inhibitor, reduced flicker-induced increases in RBF by a third of the baseline value in cats, meaning that two-thirds of the flicker-induced hyperemia is generated by NO by nNOS in neuronal and/or glial cells in the retina. 26 The current study confirmed that LAA (60 mM) as a gliotoxic compound reduced flicker-induced increases in the RBF by a third of the baseline value, indicating that two-thirds of the flicker-induced hyperemia is generated by the retinal glial cells. In addition, a flicker- The mean densities of GFAP expression in astrocytes were compared quantitatively between two groups.…”

Section: Discussionsupporting

confidence: 79%

“…We showed previously that increases in RBF during flicker stimulation were attenuated after intravitreal injection of L-NPA (5 mM), a selective neuronal NO synthase (nNOS) inhibitor, 26 suggesting that nNOS contributes to regulation of the retinal circulation during flicker stimulation. To determine whether the decrease in RBF in response to flicker stimulation in LAA (60 mM)-treated eyes resulted from reduced NO by nNOS in retinal glial cells, we measured the RBF in response to flicker stimulation in LAA (60 mM)-treated eyes 2 hours after intravitreal L-NPA injection (5 mM).…”

Section: Effects Of a Neuronal No Synthase Inhibitor In Laa-treated Eyesmentioning

confidence: 99%

“…As we showed previously, 26 we used 16-Hz stimuli as flicker stimulation because the frequency obtained a maximal RBF response in cats and the eyes were allowed to dark-adapt for 2 hours before flicker stimuli. 26 Fundus illumination was used only for alignment before dark adaptation started.…”

Section: Retinal Blood Flow Measurementsmentioning

confidence: 99%

“…26 Fundus illumination was used only for alignment before dark adaptation started. The detailed protocol and instruments used in flicker stimulation were described previously.…”

Section: Retinal Blood Flow Measurementsmentioning

confidence: 99%

“…In the current study, because the blood flow reaches a plateau 2 minutes after flicker stimulation, in the current study, we expressed the average value of three points of 120 to 180 seconds as the maximal change. 26 To assess whether LAA suppresses flicker-induced hyperemia in the retinal arterioles, we evaluated the changes in the RBF in response to flicker stimuli 24 hours after intravitreal injections of LAA or 0.01 N HCl as a control.…”

Section: Intravitreal Injections and Chemicalsmentioning

confidence: 99%

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Role of Glial Cells in Regulating Retinal Blood Flow During Flicker-Induced Hyperemia in Cats

Song

Nagaoka

Yoshioka

et al. 2015

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. 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 Nx-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% 6 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.

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Section: Discussionsupporting

confidence: 79%

Section: Effects Of a Neuronal No Synthase Inhibitor In Laa-treated Eyesmentioning

confidence: 99%

Section: Retinal Blood Flow Measurementsmentioning

confidence: 99%

“…26 Fundus illumination was used only for alignment before dark adaptation started. The detailed protocol and instruments used in flicker stimulation were described previously.…”

Section: Retinal Blood Flow Measurementsmentioning

confidence: 99%

Section: Intravitreal Injections and Chemicalsmentioning

confidence: 99%

See 3 more Smart Citations