Imaging an optogenetic pH sensor reveals that protons mediate lateral inhibition in the retina
تعليق: تأثير الأس الهيدروجيني على الحموضة والقلوية وتوصيل الكهرباء والتثبيط الطرفي للشبكية (ربما ذو صلة بضمور الشبكية المصاخب للسن. acidification was prevented by blocking a proton pump. ودور البروتونات كموصل للخلف retrograde في الجهاز العصبي هل هذا له علاقة بظهور الهذيان من عائلة الأوميبراز؟) These findings reveal that protons mediate lateral inhibition in the retina, raising the possibility that protons are unrecognized retrograde messengers elsewhere in the nervous system (هل مكتوب في المقالة المزيد عن هذه النقطة؟).--احمد شوقي محمدين 16:45، 3 نوفمبر 2016 (ت ع م)
Imaging an optogenetic pH sensor reveals that protons mediate lateral inhibition in the retina
Tzu-Ming Wang, Lars C Holzhausen & Richard H Kramer
Nature Neuroscience 17, 262–268 (2014) doi:10.1038/nn.3627
Abstract[عدل]
The reciprocal synapse between photoreceptors and horizontal cells underlies lateral inhibition and establishes the antagonistic center-surround receptive fields of retinal neurons to enhance visual contrast. Despite decades of study, the signal mediating the negative feedback from horizontal cells to cones has remained under debate because the small, invaginated synaptic cleft has precluded measurement. Using zebrafish retinas, we show that light elicits a change in synaptic proton concentration with the correct magnitude, kinetics and spatial dependence to account for lateral inhibition. Light, which hyperpolarizes horizontal cells, causes synaptic alkalinization, whereas activating an exogenously expressed ligand-gated Na+ channel, which depolarizes horizontal cells, causes synaptic acidification. Whereas acidification was prevented by blocking a proton pump, re-alkalinization was prevented by blocking proton-permeant ion channels, suggesting that distinct mechanisms underlie proton efflux and influx. These findings reveal that protons mediate lateral inhibition in the retina, raising the possibility that protons are unrecognized retrograde messengers elsewhere in the nervous system.
Subject terms: Gap junctions Neurophysiology Neurotransmitters Retina
