Quantitative and regional measurement of retinal blood flow in rats using N-isopropyl-p-[14C]-iodoamphetamine ([14C]-IMP)

Pouliot, Mylène; Deschênes, Micheline C.; Hétu, Simon; Chemtob, Sylvain; Lesk, Mark R.; Couture, Réjean; Vaucher, Elvire

doi:10.1016/j.exer.2009.08.005

Cited by 13 publications

(15 citation statements)

References 30 publications

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“…32 A significant reduction of retinal blood flow was observed in glaucomatous eyes compared with noninjured control eyes, measured from autoradiograms, at 5 weeks after induction of OHT (Figs. 4A, 4B).…”

Section: Ocular Hypertension-induced Blood Flow Impairment Is Attenuamentioning

confidence: 99%

“…To obtain C IMP (T) values, a computerized image analysis system (MCID Basic Software, v7.0; Interfocus Imaging, Linton, UK) was used to collect readings from a 0.8 mm 2 circular area at 1, 2, and 3 mm from the ONH in each eye quadrant. 32 The Ca(t) value was obtained by measuring radioactivity in the collected blood samples using a scintillation counter (LS6500; Beckman Coulter, Mississauga, ON, Canada).…”

Section: Quantitative Blood Flow Autoradiographymentioning

confidence: 99%

“…32 Briefly, animals were euthanized with an overdose of sodium pentobarbital (240 mg/kg) and the eyes were enucleated. Retinas were rapidly dissected out and placed in high Mg 2þ /low Ca 2þ dissociation buffer (145 mM NaCl, 5 mM KCl, 10 mM HEPES, 5 mM D-glucose, 0.1 mM CaCl 2 , 8 mM MgCl 2 , pH 7.3), and cut into several pieces, followed by trituration with a fire-polished glass pipette (0.3 mm).…”

Section: In Vitro Retinal Microvasculature Preparationmentioning

confidence: 99%

“…32 Briefly, [ 14 C]-IMP (100 lCi/kg; PerkinElmer, Boston, MA) was infused through a femoral vein catheter over a 30-second period at a constant rate of 1.2 mL/min. Arterial blood samples were collected at a continuous rate until euthanasia (2 minutes after […”

Section: Quantitative Blood Flow Autoradiographymentioning

confidence: 99%

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Acetylcholinesterase Inhibition Promotes Retinal Vasoprotection and Increases Ocular Blood Flow in Experimental Glaucoma

Almasieh

Macintyre

Pouliot

et al. 2013

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. A clear correlation between vascular deficits and retinal ganglion cell (RGC) loss in glaucoma has not yet been established. The question arose as to whether there is loss of inner retinal vessels following intraocular pressure (IOP) increase and, if so, whether it occurs prior to, concomitantly with, or after RGC death. We also sought to establish whether galantamine, an acetylcholinesterase inhibitor that promotes RGC survival, can protect the retinal microvasculature and enhance blood flow in experimental glaucoma. METHODS. Ocular hypertension was induced in BrownNorway rats by injection of hypertonic saline into an episcleral vein. Retinas were processed for simultaneous visualization of the retinal microvasculature and RGCs in glaucomatous and control eyes. Retinal blood flow was examined by quantitative autoradiography using N-isopropyl-p-[14 C]-iodoamphetamine. Vascular reactivity was further assessed using an in vitro retinal microvasculature preparation.RESULTS. Substantial loss of retinal capillaries was observed after induction of ocular hypertension. The onset of both microvasculature and RGC loss occurred early and proceeded at a similar rate for at least 5 weeks after the initial damage. Systemic administration of galantamine preserved microvasculature density and improved retinal blood flow in glaucomatous retinas. The vasoactive effects of galantamine on retinal microvessels occurred through activation of muscarinic acetylcholine receptors both in vitro and in vivo.CONCLUSIONS. The onset and progression of microvessel and RGC loss are concomitant in experimental glaucoma, suggesting a tight codependence between these cellular compartments. Early interventions aimed to protect the retinal microvasculature and improve blood supply are likely to be beneficial for the treatment of glaucoma.

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Section: Ocular Hypertension-induced Blood Flow Impairment Is Attenuamentioning

confidence: 99%

Section: Quantitative Blood Flow Autoradiographymentioning

confidence: 99%

Section: In Vitro Retinal Microvasculature Preparationmentioning

confidence: 99%

Section: Quantitative Blood Flow Autoradiographymentioning

confidence: 99%

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Acetylcholinesterase Inhibition Promotes Retinal Vasoprotection and Increases Ocular Blood Flow in Experimental Glaucoma

Almasieh

Macintyre

Pouliot

et al. 2013

Invest. Ophthalmol. Vis. Sci.

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“…In a second study, we used ovariectomized (OVx) rats, a model for human menopause, to determine the pure contribution of estrogens to blood flow changes by exposing the rats to 17␤-E 2 treatment and measuring the retinal tissue perfusion using the diffusible tracer N-isopropyl-p-[ 14 C]-iodoamphetamine ([ 14 C]-IMP). 32,33 Rats were chosen, as they are widely used in ovarian aging research with well-documented pathobiologic, cardiologic, and reproductive endpoints, and because ERs are also present in their retina. 25,34 …”

Section: Purposementioning

confidence: 99%

Postmenopausal Hormone Therapy Increases Retinal Blood Flow and Protects the Retinal Nerve Fiber Layer

Deschênes

Descovich

Moreau³

et al. 2010

Invest. Ophthalmol. Vis. Sci.

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MRI of retinal and choroidal blood flow with laminar resolution

Muir

Duong

2010

NMR in Biomedicine

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The retina is nourished by two distinct circulations: the retinal vessels within the inner retina and the choroidal vessels behind the neural retina. The outer nuclear layer and the inner and outer segments of the photoreceptors in between are avascular. The aim of this study was to determine whether arterial spin labeling MRI could provide sufficient resolution to differentiate between quantitative retinal blood flow (rBF) and choroidal blood flow (chBF), and whether this technique is sufficiently sensitive to detect vascular-specific blood flow (BF) changes modulated by anesthetics. Arterial spin labeling MRI was performed at 42 × 42 × 400 µm 3 in the mouse retina at 7 T, and was used to investigate the effects of isoflurane and ketamine/xylazine anesthesia on rBF and chBF. MRI yielded unambiguous differentiation of rBF, chBF and the avascular layer in between. Under isoflurane, chBF was 7.7 ± 2.1 mL/g/min and rBF was 1.3 ± 0.44 mL/g/min (mean ± SD, n = 7, p < 0.01). Under ketamine/xylazine anesthesia in the same animals, chBF was 4.3 ± 1.9 mL/g/min and rBF was 0.88 ± 0.22 mL/g/min (p < 0.01). Under ketamine/xylazine anesthesia, rBF was lower by 29% (P < 0.01) and chBF by 42% (P < 0.01) relative to isoflurane. This study demonstrates, for the first time, the quantitative imaging of rBF and chBF in vivo, providing a new method to study basal values and alterations of rBF and chBF.

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Quantitative and regional measurement of retinal blood flow in rats using N-isopropyl-p-[14C]-iodoamphetamine ([14C]-IMP)

Cited by 13 publications

References 30 publications

Acetylcholinesterase Inhibition Promotes Retinal Vasoprotection and Increases Ocular Blood Flow in Experimental Glaucoma

Acetylcholinesterase Inhibition Promotes Retinal Vasoprotection and Increases Ocular Blood Flow in Experimental Glaucoma

Postmenopausal Hormone Therapy Increases Retinal Blood Flow and Protects the Retinal Nerve Fiber Layer

MRI of retinal and choroidal blood flow with laminar resolution

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