• Title, Summary, Keyword: ERG (Electroretinogram)

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Gap Junction Contributions to the Goldfish Electroretinogram at the Photopic Illumination Level

  • Kim, Doh-Yeon;Jung, Chang-Sub
    • The Korean Journal of Physiology and Pharmacology
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    • v.16 no.3
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    • pp.219-224
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    • 2012
  • Understanding how the b-wave of the electroretinogram (ERG) is generated by full-field light stimulation is still a challenge in visual neuroscience. To understand more about the origin of the b-wave, we studied the contributions of gap junctions to the ERG b-wave. Many types of retinal neurons are connected to similar and different neighboring neurons through gap junctions. The photopic (cone-dominated) ERG, stimulated by a small light beam, was recorded from goldfish (Carassius auratus) using a corneal electrode. Data were obtained before and after intravitreal injection of agents into the eye under a photopic illumination level. Several agents were used to affect gap junctions, such as dopamine D1 and D2 receptor agonists and antagonists, a nitric oxide (NO) donor, a nitric oxide synthase (NOS) inhibitor, the gap junction blocker meclofenamic acid (MFA), and mixtures of these agents. The ERG b-waves, which were enhanced by MFA, sodium nitroprusside (SNP), SKF 38393, and sulpiride, remained following application of a further injection of a mixture with MFA. The ERG b-waves decreased following $N^G$-nitro-L-arginine methyl ester (L-NAME), SCH 23390, and quinpirole administration but were enhanced by further injection of a mixture with MFA. These results indicate that gap junction activity influences b-waves of the ERG related to NO and dopamine actions.

Physiological and Behavioral Studies on the Stimulating Effect of Strobe Light-IV Electroretinogram of Jack Mackerel by Strobe Light Frequency and Intensity (스트로보광의 위협효과에 관한 행동생리학적 연구-IV 스트로보광의 섬광빈도 및 강도에 의한 전갱이의 망막활동전위)

  • An, Yeong-Il
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.40 no.2
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    • pp.132-137
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    • 2004
  • In order to assess electrophysiological responses of fish, a recording of Electroretinogram (ERG) was made on the dark-adapted eyes of anesthetized jack mackerel Trachurus japonicus in the strobe-flash frequency range of 1.7~25 Hz and in the intensity range of 56~415 lx.s. The amplitude change of the ERG is highest at the moment when the strobe light is irradiated and becomes weakest soon after, then gradually increases and becomes stable. The amplitude of the ERG by strobe flash frequencies looked stable tendency after about 12~17 minutes elapsed. During the test duration of 30 minutes, the maximum of amplitude change and stimulation amount over all the tested frequencies was found at 10 Hz. The reduction of the flash intensity caused the decrease in the amplitude and stimulation amount.

De-Noising of Electroretinogram Signal Using Wavelet Transforms (웨이브렛 변환을 이용한 망막전도 신호의 잡음제거)

  • Seo, Jung-Ick;Park, Eun-Kyoo
    • Journal of Korean Ophthalmic Optics Society
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    • v.17 no.2
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    • pp.203-207
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    • 2012
  • Purpose: Electroretinogram(ERG) signal noise as well as conducting other bio-signal measurement were generated. It was intened to enhance the accuracy of retinal-related diagnosis with removing signal noise. Methods: Sampling signal was made with generating 60 Hz noise and white noise. The noise were removed using wavelet transforms and bandpass filter. De-noising frequency was compared with Fourier transform spectrum. Removed noises were compared numerically using SNR(signal to noise ratio). Results: The result compared Fourier transform spectrum was showed that 60 Hz noise removed completely and most of white noise was removed by wavelet transforms. 60 Hz and the white noise remained using bandpass filters. The result compared SNR showed that wavelet transforms was 22.8638 and bandpass filter was 4.0961. Conclusions: Wavelet transform showed less signal distortion in removing noise. ERG signal is expected to improve the accuracy of retinal-related diagnosis.

Effect of Age and Gender on Electroretinogram in 34 Client-owned Healthy Dogs (건강한 내원견에서 나이와 성별이 망막전위도에 미치는 영향)

  • Kim, Kyung-Hee;Jeong, Soon-Wuk
    • Journal of Veterinary Clinics
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    • v.29 no.2
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    • pp.124-129
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    • 2012
  • The purpose of this study was to identify the effect of age and gender on the value of electroretinogram (ERG) in healthy dogs. The ERG responses of 68 eyes of 34 dogs (22 males, 12 females) were recorded following the diagnostic protocol for dogs recommended by International Society for Clinical Electrophysiology of Vision under general anesthesia using medetomidine and tiletamine-zolazepam combination. There were significant differences in the implicit time of a-wave of Hi-int R & C response among age groups (P < 0.05) and in the implicit time of a-wave of cone response between male and female (P < 0.05). The rest ERG responses seem to be not affected by age and gender of healthy dogs.

A Study of Vision Biomembrane Assembly using Photoreactive Protein Adsorbed Polypyrrole Film

  • Lim, Jeong-Ok;Huh, Jeung-Soo
    • Journal of Sensor Science and Technology
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    • v.9 no.3
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    • pp.208-212
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    • 2000
  • A protein based vision biomembrane was fabricated by adsorbing bacteriorhodopsin into electrochemically polymerized polypyrrole film substrate mainly through strong electrostatic interaction. The immobilized bacteriorhodopsin on the polypyrrole film was demonstrated by SEM and SRET. The light signal transducing function from the bacteriorhodopsin which was adsorbed into Polypyrrole film was evaluated by electroretinogram(ERG). A wave form analysis of the electroretinogram indicated that the adsorbed bacteriorhodopsin retained its activity and light signal was obtained from the protein for at least one month.

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Evaluation of electroretinogram and retinal histopathology in rabbits administered DA-8159, a selective PDE 5 inhibitor

  • Kang, Kyung-Koo;Ahn, Gook-Jun;Sohn, Yong-Sung;Shim, Hyun-Joo;Ahn, Byung-Ok;Kim, Won-Bae;Cho, Ho-Kyun
    • Proceedings of the PSK Conference
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    • pp.250.1-250
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    • 2002
  • DA-8159. a selective inhibitor of phosphodiesterase type 5 (PDE5: IC$\sub$50/ 5ng/$m\ell$). is being developed as a new treatment for erectile dysfunction. Since DA-8159 has been shown to inhibit PDE6 enzyme (IC$\sub$53ng/$m\ell$). we evaluated the effect of DA-8159 on electroretinogram (ERG) and retinal histopathology in rabbits. The effect of oral DA-8159 (5 to 30mg/kg) on ERG recordings was investigated at pre-treatment. 1 and 5 hrs after administration in rabbits. (omitted)

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Clinical Relevance of Mobile Phone Interference with Electroretinography in Healthy Dogs: Experimental Study

  • Jung, Sunjun;Lee, Dongbin;Kim, Jury;Kim, Minsu;Heo, Suyoung;Kim, Namsoo
    • Journal of Veterinary Clinics
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    • v.37 no.3
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    • pp.130-134
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    • 2020
  • This study aimed to confirm the effects that the mobile phone has on Electroretinogram (ERG). The ERG responses of three groups of healthy dogs, five in each group, were studied. ERG test was performed consecutively before and after the mobile phone was carried out. For group A, music was played with the sound on; for group B, music was played but the sound off; and for group C, the phone was set on the airplane mode. In the presence of a mobile phone, the amplitudes of a- and b-wave were increased in all groups. The a- and b-wave amplitudes at the flash intensity of 3,000 mcd·s/㎡ were significantly increased in all groups (p < 0.05). Based on the results, it is recommended to conduct ERG test in the absence of a mobile phone for the accurate evaluation of the retinal function.

Synergism Between Zinc and Taurine in the Visual Sensitivity of the Bullfrog's Eye

  • Kim, Hyun-Jung;Kim, You-Young
    • Journal of Photoscience
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    • v.7 no.3
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    • pp.115-121
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    • 2000
  • Although there are high concentrations of zinc and taurine in ocular tissue, their exact role and correlation in the visual process are not clear. The purpose of present study was to clarity this point using electroretinogram (ERG) recording and spectrophotometer measurements before and after zinc and taurine treatment in bullfrog's eye. The optimal zinc concentration used in this study was 10$^{-2}$ M ZnCl$_2$120 ${mu}ell$/12$m\ell$ ringer solution while the optimal turine concentration was 10$^{-2}$ M taurine 12${mu}ell$/12$m\ell$ ringer solution. For the effects of zinc and taurine on the retinal function, the changes of ERG parameters (especially threshold and b-wave) and absorption spectra were observed before and after treatment. It is noteworthy that high concentrations of zinc and taurine present in the retinal pigment epithelium and the retina. Our results indicate that dark-adapted ERG threshold became elevated and the peak amplitude of b-wave was increased with zinc and taurine treatment. Furthermore there are some synergism effects between zinc and taurine as a result of co-treatment. In spectral scan, absorbance increment due to zinc and taurine treatment was shown over the whole range of spectral range (300-750 nm) with some differences in absorbance increment depending on the case of treatment. As the results of above we believe that zinc and taurine, which are abundant in the retinal pigment epithelium and the retina particularly, may be essential factors for visual process, have some synergism with each other and be required to improve the visual sensitivity during visual adaptation.

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Electrophysiological and Histologic Evaluation of the Time Course of Retinal Degeneration in the rd10 Mouse Model of Retinitis Pigmentosa

  • Jae, Seol A;Ahn, Kun No;Kim, Ji Young;Seo, Je Hoon;Kim, Hyong Kyu;Goo, Yong Sook
    • The Korean Journal of Physiology and Pharmacology
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    • v.17 no.3
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    • pp.229-235
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    • 2013
  • Among several animal models of retinitis pigmentosa (RP), the more recently developed rd10 mouse with later onset and slower rate of retinal degeneration than rd1 mouse is a more suitable model for testing therapeutic modalities. We therefore investigated the time course of retinal degeneration in rd10 mice before adopting this model in our interventional studies. Electroretinogram (ERG) recordings were carried out in postnatal weeks (PW) 3~5 rd10 (n=23) and wild-type (wt) mice (n=26). We compared the amplitude and implicit time of the b-wave of ERG records from wt and rd10 mice. Our results showed that b-wave amplitudes in rd10 mice were significantly lower and the implicit time of b-waves in rd10 mice were also significantly slower than that in wt mice ($20{\sim}160{\mu}V$ vs. $350{\sim}480{\mu}V$; 55~75 ms vs. 100~150 ms: p<0.001) through PW3 to PW5. The most drastic changes in ERG amplitudes and latencies were observed during PW3 to PW4. In multichannel recording of rd10 retina in PW2 to PW4.5, we found no significant difference in mean spike frequency, but the frequency of power spectral peak of local field potential at PW3 and PW3.5 is significantly different among other age groups (p<0.05). Histologic examination of rd10 retinae showed significant decrease in thickness of the outer nuclear layer at PW3. TUNEL positive cells were most frequently observed at PW3. From these data, we confirm that in the rd10 mouse, the most precipitous retinal degeneration occurs between PW3~PW4 and that photoreceptor degeneration is complete by PW5.

Modification of Retinal Function by Hypothermia and Hyperthermia

  • Chon, Young-Shin;Kim, You-Young
    • Journal of Photoscience
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    • v.7 no.4
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    • pp.161-167
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    • 2000
  • Temperature-dependent electroretinogram responses were investigated in the dark adapted bullfrog eyes within the physiological temperature range 0-40$\^{C}$. In hypothermic process(25→0→25$\^{C}$), the amplitude of b-and c-wave decreased with lowering the temperature again. Both b-wave amplitude and threshold responses were maximal around 15$\^{C}$ during the temperature increment. Upon warming to room temperature again (25$\^{C}$), the b-wave amplitude was approximately doubled as compared to that of control without temperature changes. During the hyperthermic process (25→40→25$\^{C}$), however, the responses decreased with warming, and the wave amplitude failed to recover by cooling to 25$\^{C}$ again. As describe above, the recoveries of ERG in both processes show the striking difference. The hypothermia induces the amplification of the b-wave, that is, enhances the retinal function with the temperature recovery toward room temperature. While the hypertherima produces the decrease of the b-wave even though recovered to room temperature, which indicates an irreversible retina. The morphological alteration is shown both hypothermic and hyperthermic process, such as an appearance of large vacuoles and degenerating outer segments, more intense in hyperthermia, similar to light induced damage.

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