ABSTRACT
During the last decade, a large number of studies have focused on the development of nanomaterials for medical applications. Therefore, the present study was designed to evaluate the stimulatory effects of zinc oxide nanoparticles in the vertebrate visual system. Zinc oxide nanoparticles were synthesized and characterized through photoluminescence, ultraviolet (UV)-visible spectroscopy, field emission scanning electron microscopy and X-ray diffraction measurements. Furthermore, various electrophysiological recordings were obtained from the bullfrog eyecup preparations under various treatment conditions. Photoluminescence data showed a central peak at 386 nm while the UV-visible spectrum showed a sharp absorption band centered around 367 nm. Field emission scanning electron microscopy and X-ray diffraction measurements showed that synthesized zinc oxide nanoparticles have a polycrystalline wurtzite structure, with a round to oval shape and an average particle size of > 40 nm. Electroretinography (ERG) demonstrated that zinc oxide nanoparticles significantly increased the ERG b-wave amplitude in dark-adapted bullfrog eyecups and in the presence of background illumination. Zinc oxide nanoparticles also improved the visual sensitivity by 0.7 log unit of light intensity and shortened the duration of rhodopsin regeneration. Based on the results obtained, it was concluded that zinc oxide nanoparticles may be used to improve visual functions. The present study may add new dimensions to the biomedical applications of nanomaterials in eye research.
Subject(s)
Light , Nanoparticles , Ocular Physiological Phenomena/drug effects , Vision, Ocular/drug effects , Zinc Oxide/pharmacology , Adaptation, Ocular/drug effects , Animals , Electrophysiological Phenomena/drug effects , Electrophysiological Phenomena/radiation effects , Electroretinography , Eye/drug effects , Eye/radiation effects , Microscopy, Electron, Scanning , Microscopy, Electron, Transmission , Ocular Physiological Phenomena/radiation effects , Rana catesbeiana , Up-Regulation/drug effects , X-Ray DiffractionABSTRACT
ETHNOPHARMACOLOGICAL RELEVANCE: The fruit of Rubus coreanus (Rosaceae) is traditionally used as an aphrodisiac, astringent, restorative and tonic in Asian countries. It is advised for treating diseases related to liver, kidney and urinary dysfunction, premature greying, blurred vision, infertility, impotence and premature ejaculation. Additionally, there is a long history of different parts of the plants being used in the treatment of ophthalmic diseases. However, no scientific studies have been undertaken to determine the effects of Rubus coreanus in visual processes of the vertebrate retina. AIM OF STUDY: The purpose of the present study was to investigate the positive effects of Rubus coreanus extracts on visual processes in the vertebrate's eye. MATERIALS AND METHODS: Electroretinogram (ERG) techniques were used to record the responses from a bullfrog's eye cup preparations. Active pharmacological agents were used to block specific receptors in the retina and to leave others unaffected. Lipid peroxidation in the retina was generated by adding FeSO(4)+Na-ascorbate. RESULTS: It was observed that both dark- and light-adapted ERG b-wave peak amplitude significantly increases with Rubus coreanus treatment. It was found that Rubus coreanus acts as a retinal neural antagonist but not as GABA receptor antagonist. Rubus coreanus treatment lowered the duration of rhodopsin regeneration. The results obtained indicated that Rubus coreanus protects against lipid peroxidation drop off ERG amplitude in retina. CONCLUSION: Based on results obtained, it is suggested that Rubus coreanus can potentially improve visual sensitivity and can be used to treat pathophysiological conditions of eye.
Subject(s)
Plant Extracts/pharmacology , Rana catesbeiana/physiology , Rosaceae/chemistry , Vision, Ocular/drug effects , Animals , Electroretinography , GABA Antagonists/pharmacologyABSTRACT
The purpose of the present study was to investigate the effect of red ginseng (Panax ginseng) extracts on the visual process in bullfrog's eye. The results obtained indicated that both dark-adapted and light-adapted ERG b-wave peak amplitude was increased with red ginseng treatment. Furthermore, the ERG sensitivity was elevated by 1.4 log units of light intensity. It was found that red ginseng acts as a retinal neural antagonist but not as a GABA receptor antagonist. Red ginseng improved the alcohol dehydrogenase activity and speeded up the delivery of 11 CIS-retinal from retinal pigment epithelium (RPE) to the outer disc of the photoreceptors which resulted in decreased regeneration time of rhodopsin. In the spectral scan, red ginseng treatment brings an increment in absorbance over the whole spectral range (300-800 nm) with maximum difference at around 500 nm. It is concluded that red ginseng may be used to improve visual process, and can potentially be used to treat certain ophthalmic diseases.