Frequency spectrum and amplitude analysis of dark- and light-adapted oscillatory potentials in albino mouse, rat and rabbit

Zhang, Keqing; Yao, Gang; Gao, Yuanfang; Hofeldt, K.J.

doi:10.1007/s10633-007-9061-1

Cited by 16 publications

(10 citation statements)

References 32 publications

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“…2. The oscillatory potentials exhibited a peak frequency of ∼90–110 Hz, which is comparable to that of dark-adapted mouse ERGs in vivo [31]. A fast Fourier transform was used to derive the power spectrum of the oscillatory potentials, from stimulus onset to the half-width of the b-wave recovery phase (∼240 ms).…”

Section: Methodsmentioning

confidence: 99%

P2X7R modulation of visually evoked synaptic responses in the retina

Chavda¹,

Luthert

Salt³

2016

Purinergic Signalling

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P2X7Rs are distributed throughout all layers of the retina, and thus, their localisation on various cell types puts into question their specific site(s) of action. Using a dark-adapted, ex vivo mouse retinal whole mount preparation, the present study aimed to characterise the effect of P2X7R activation on light-evoked, excitatory RGC ON-field excitatory post-synaptic potentials (fEPSPs) and on outer retinal electroretinogram (ERG) responses under comparable conditions. The pharmacologically isolated NMDA receptor-mediated RGC ON-fEPSP was reduced in the presence of BzATP, an effect which was significantly attenuated by A438079 and other selective P2X7R antagonists A804598 or AF27139. In physiological Krebs medium, BzATP induced a significant potentiation of the ERG a-wave, with a concomitant reduction in the b-wave and the power of the oscillatory potentials. Conversely, in the pharmacologically modified Mg2+-free perfusate, BzATP reduced both the a-wave and b-wave. The effects of BzATP on the ERG components were suppressed by A438079. A role for P2X7R function in visual processing in both the inner and outer retina under physiological conditions remains controversial. The ON-fEPSP was significantly reduced in the presence of A804598 but not by A438079 or AF27139. Furthermore, A438079 did not have any effect on the ERG components in physiological Krebs but potentiated and reduced the a-wave and b-wave, respectively, when applied to the pharmacologically modified medium. Therefore, activation of P2X7Rs affects the function in the retinal ON pathway. The presence of a high concentration of extracellular ATP would most likely contribute to the modulation of visual transmission in the retina in the pathophysiological microenvironment.

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Section: Methodsmentioning

confidence: 99%

P2X7R modulation of visually evoked synaptic responses in the retina

Chavda¹,

Luthert

Salt³

2016

Purinergic Signalling

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“…Although the neural generator of the OPs has not been precisely defined, it is thought that they originate from amacrine cell feedback [4,5]. The major features of OPs are similar across species, but lower mammals have been found to have generally lower OP frequency spectra than higher mammals [6,7]. The source of the OPs in primates is in the inner retina.…”

Section: Introductionmentioning

confidence: 99%

Human oscillatory potentials: intensity-dependence of timing and amplitude

Hancock

Kraft

2008

Doc Ophthalmol

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Oscillatory potentials (OPs) have been described as reduced in amplitude or delayed in diabetic retinopathy, glaucoma, and vascular occlusions. Although OPs are thought to have useful diagnostic applications, some of their basic physiologic properties remain to be fully described. In the present study, we examined the relationship between the timing and amplitude of OPs and stimulus intensity. Five normal volunteers had one eye anesthetized and dilated. Dark-adapted full-field ERGs were recorded to white stimuli of 0.0125-40 cd s/m(2). The timing of the OPs was measured as the sum of the time to the peak (TTP) of four peaks beginning at 15 ms after the stimulus. The amplitude was taken as the sum of the amplitudes of those same peaks. As an alternative value, OP strength was represented by the area under the OP curve or power around 150 Hz (+/-30 Hz) in the frequency domain. The OP timing, as measured by TTP, was found to be inversely related to stimulus intensity. OP-amplitudes grew with intensity, but then declined for stimulus intensities above about 4 cd s/m(2). At bright light intensities, the TTP continued to shorten, yet amplitudes, power, and area all declined. Individual OPs behaved similarly and reflected the overall response pattern of the group as a whole. Brighter stimuli produced larger, faster OPs for stimulus strengths up to the intensity standard used to produce OPs (3.5 cd s/m(2)). We have extended the range of stimuli to some 10-fold higher than the ISCEV standard for producing OPs and found that the timing continued to accelerate but that OP-amplitudes, OP-area, and OP-power all decline at higher stimulus intensities. These alternative measures of OP energy are easily measured and may be useful for further studies.

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“…OPs are thought to reflect the activity of the amacrine cells in the inner retina. A limitation of the current study is suboptimal bandpass filtering setting for the rat retina that may have missed some lower frequency components of the OPs (Zhang et al, 2007). However, the current filter settings did provide clear analysis of the higher frequency components without potential interference from the a- or b-waves.…”

Section: Discussionmentioning

confidence: 99%

Whole-eye electrical stimulation therapy preserves visual function and structure in P23H-1 rats

Hanif

Kim

Thomas

et al. 2016

Experimental Eye Research

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Low-level electrical stimulation to the eye has been shown to be neuroprotective against retinal degeneration in both human and animal subjects, using approaches such as subretinal implants and transcorneal electrical stimulation. In this study, we investigated the benefits of whole-eye electrical stimulation (WES) in a rodent model of retinitis pigmentosa. Transgenic rats with a P23H-1 rhodopsin mutation were treated with 30 min of low-level electrical stimulation (4 μA at 5 Hz; n = 10) or sham stimulation (Sham group; n = 15), twice per week, from 4 to 24 weeks of age. Retinal and visual functions were assessed every 4 weeks using electroretinography and optokinetic tracking, respectively. At the final time point, eyes were enucleated and processed for histology. Separate cohorts were stimulated once for 30 min, and retinal tissue harvested at 1 h and 24 h post-stimulation for real-time PCR detection of growth factors and inflammatory and apoptotic markers. At all time-points after treatment, WES-treated rat eyes exhibited significantly higher spatial frequency thresholds than untreated eyes. Inner retinal function, as measured by ERG oscillatory potentials (OPs), showed significantly improved OP amplitudes at 8 and 12 weeks post-WES compared to Sham eyes. Additionally, while photoreceptor segment and nuclei thicknesses in P23H-1 rats did not change between treatment groups, WES-treated eyes had significantly greater numbers of retinal ganglion cell nuclei than Sham eyes at 20 weeks post-WES. Gene expression levels of brain-derived neurotrophic factor (BDNF), caspase 3, fibroblast growth factor 2 (FGF2), and glutamine synthetase (GS) were significantly higher at 1 h, but not 24 h after WES treatment. Our findings suggest that WES has a beneficial effect on visual function in a rat model of retinal degeneration and that post-receptoral neurons may be particularly responsive to electrical stimulation therapy.

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Frequency spectrum and amplitude analysis of dark- and light-adapted oscillatory potentials in albino mouse, rat and rabbit

Cited by 16 publications

References 32 publications

P2X7R modulation of visually evoked synaptic responses in the retina

P2X7R modulation of visually evoked synaptic responses in the retina

Human oscillatory potentials: intensity-dependence of timing and amplitude

Whole-eye electrical stimulation therapy preserves visual function and structure in P23H-1 rats

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