43 research outputs found
Potassium Channel and NKCC Cotransporter Involvement in Ocular Refractive Control Mechanisms
Myopia affects well over 30% of adult humans globally. However, the underlying physiological mechanism is little understood. This study tested the hypothesis that ocular growth and refractive compensation to optical defocus can be controlled by manipulation of potassium and chloride ion-driven transretinal fluid movements to the choroid. Chicks were raised with +/−10D or zero power optical defocus rendering the focal plane of the eye in front of, behind, or at the level of the retinal photoreceptors respectively. Intravitreal injections of barium chloride, a non-specific inhibitor of potassium channels in the retina and RPE or bumetanide, a selective inhibitor of the sodium-potassium-chloride cotransporter were made, targeting fluid control mechanisms. Comparison of refractive compensation to 5mM Ba2+ and 10−5 M bumetanide compared with control saline injected eyes shows significant change for both positive and negative lens defocus for Ba2+ but significant change only for negative lens defocus with bumetanide ; ; ; ; ; ). Vitreous chamber depths showed a main effect for drug conditions with less depth change in response to defocus shown for Ba2+ relative to Saline, while bumetanide injected eyes showed a trend to increased depth without a significant interaction with applied defocus. The results indicate that both K channels and the NKCC cotransporter play a role in refractive compensation with NKCC blockade showing far more specificity for negative, compared with positive, lens defocus. Probable sites of action relevant to refractive control include the apical retinal pigment epithelium membrane and the photoreceptor/ON bipolar synapse. The similarities between the biometric effects of NKCC inhibition and biometric reports of the blockade of the retinal ON response, suggest a possible common mechanism. The selective inhibition of refractive compensation to negative lens in chick by loop diuretics such as bumetanide suggests that these drugs may be effective in the therapeutic management of human myopia
cAMP stimulates transepithelial short-circuit current and fluid transport across porcine ciliary epithelium
2016-2017 > Academic research: refereed > Publication in refereed journal201811_a bcmaVersion of RecordPublishe
Characterization of anoctamin in porcine ciliary epithelium
ARVO 2020 : Association for Research in Vision & Ophthalmology Annual Meeting, May 3, 2020 - May 7, 2020, Baltimore, MD, US202011 bcrcMetadata onlyPublishe
Characterization and regulation of gap junctions in porcine ciliary epithelium
2017-2018 > Academic research: refereed > Publication in refereed journal201812 bcrcVersion of RecordPublishe
Mechanistic effects of Baicalein on aqueous humor drainage and intraocular pressure
202207 bckwVersion of RecordOthersHealth Medical Research Fund; PolyU grants; The Government of the Hong Kong Special Administrative Region & Innovation and Technology Fund; Shenzhen Science and Technology Innovation Commission; Henry G. Leong Endowed Professorship in Elderly Vision Health; National Eye Institute, USAPublishe