TRPM3 Expression in Mouse Retina
TRPM3 Expression in Mouse Retina
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DOI：
10.1371/journal.pone.0117615
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发表时间：
2015-02-13
期刊：
影响因子：
3.7
通讯作者：
Duvoisin, Robert M.
中科院分区：
文献类型：
--
作者：
Brown, R. Lane;Xiong, Wei-Hong;Duvoisin, Robert M.
瞬态受体电位（TRP）通道是一类阳离子渗透离子通道，通过将环境变化转化为细胞电压和钙信号，在感觉系统中起着至关重要的作用。在视网膜内，美拉他汀TRP家族的两个密切相关的成员TRPM1和TRPM3是高表达的。TRPM1已被证明是on双极细胞对光的去偏振反应所必需的，但TRPM3在视网膜中的作用尚不清楚。针对TRPM3 c末端的抗体对小鼠视网膜进行免疫组化染色，标记了内丛状层（IPL）和神经节细胞层中的一部分细胞。在IPL内，OFF膜下的TRPM3免疫荧光明显强于ON膜下。视网膜电图记录显示，TRPM3（-/-）小鼠的暗位和光位a波和b波正常，表明TRPM3在外视网膜的视觉加工中不起主要作用。通过钙显像和膜片钳记录免疫纯化的视网膜神经节细胞来测定TRPM3活性。应用TRPM3激动剂硫酸孕烯醇酮（PS），在野生型和TRPM1（-/-）小鼠中，大约40%的细胞中刺激了细胞内钙的增加，并且PS刺激的钙增加被联合应用mefenamic acid（一种TRPM3拮抗剂）阻断。在TRPM3（-/-）小鼠的神经节细胞中未观察到ps刺激的荧光变化。同样，在野生型视网膜神经节细胞中记录到可以被甲氧胺酸阻断的ps刺激电流，但在TRPM3（-/-）小鼠的神经节细胞中却没有。
Transient receptor potential (TRP) channels constitute a large family of cation permeable ion channels that serve crucial functions in sensory systems by transducing environmental changes into cellular voltage and calcium signals. Within the retina, two closely related members of the melastatin TRP family, TRPM1 and TRPM3, are highly expressed. TRPM1 has been shown to be required for the depolarizing response to light of ON-bipolar cells, but the role of TRPM3 in the retina is unknown. Immunohistochemical staining of mouse retina with an antibody directed against the C-terminus of TRPM3 labeled the inner plexiform layer (IPL) and a subset of cells in the ganglion cell layer. Within the IPL, TRPM3 immunofluorescence was markedly stronger in the OFF sublamina than in the ON sublamina. Electroretinogram recordings showed that the scotopic and photopic a- and b-waves of TRPM3(-/-) mice are normal indicating that TRPM3 does not play a major role in visual processing in the outer retina. TRPM3 activity was measured by calcium imaging and patch-clamp recording of immunopurified retinal ganglion cells. Application of the TRPM3 agonist, pregnenolone sulfate (PS), stimulated increases in intracellular calcium in similar to 40% of cells from wild type and TRPM1(-/-) mice, and the PS-stimulated increases in calcium were blocked by co-application of mefenamic acid, a TRPM3 antagonist. No PS-stimulated changes in fluorescence were observed in ganglion cells from TRPM3(-/-) mice. Similarly, PS-stimulated currents that could be blocked by mefenamic acid were recorded from wild type retinal ganglion cells but were absent in ganglion cells from TRPM3(-/-) mice.