Low-Threshold Calcium Channel Subunit Cav3.3 Is Specifically Localized in GABAergic Neurons of Rodent Thalamus and Cerebral Cortex
Low-Threshold Calcium Channel Subunit Cav3.3 Is Specifically Localized in GABAergic Neurons of Rodent Thalamus and Cerebral Cortex
复制标题
DOI：
10.1002/cne.22567
复制
发表时间：
2011-04-15
影响因子：
2.5
通讯作者：
Jones, Edward G.
中科院分区：
文献类型：
--
作者：
Liu, Xiao-Bo;Murray, Karl D.;Jones, Edward G.
Relatively little is known about the subcellular localization of low threshold Ca2+ channels (T-channels) in the brain. Using immunocytochemical labeling and preem-bedding immunoperoxidase and silver-enhanced immunogold electron microscopy, we localized T-channel subunit Ca(v)3.3 in rodent cerebral cortex and thalamus. Double immunofluorescent staining demonstrated that Ca(v)3.3-labeled neurons in cerebral cortex are a subgroup of GABAergic interneurons that coexpress calbindin and in half of the cases parvalbumin. In the thalamus, virtually all reticular nucleus (RTN) neurons were immunopositive for Ca(v)3.3, while neurons in dorsal thalamic nuclei were nonimmunoreactive. At the electron microscopic (EM) level, in cortical layers IV-V and RTN neurons, Ca(v)3.3 immunoreactivity was mainly associated with membranes of dendrites but with some localization in cytoplasm. None was found in axon terminals. In cortex, approximate to 73% of immunogold particles were present in close proximity to synaptic contacts (< 0.5 mu m from the postsynaptic density), while 27% were distributed along membranes at extrasynaptic sites (> 0.5 mu m from the postsynaptic density). In RTN, approximate to 57% particles were evenly distributed along perisynaptic membranes and the remaining 43% of particles were diffusely localized at extrasynaptic membranes. The density of particles along the dendritic membranes of cortical neurons was 40% higher than in RTN neurons. These results suggest that Ca(v)3.3 plays a role in regulating GABAergic neurons whose actions underlie thalamocortical rhythmicity. J.Comp。内罗尔。 519: 1181-1195, 2011. (C) 2010 Wiley-Liss, Inc.
Relatively little is known about the subcellular localization of low threshold Ca2+ channels (T-channels) in the brain. Using immunocytochemical labeling and preem-bedding immunoperoxidase and silver-enhanced immunogold electron microscopy, we localized T-channel subunit Ca(v)3.3 in rodent cerebral cortex and thalamus. Double immunofluorescent staining demonstrated that Ca(v)3.3-labeled neurons in cerebral cortex are a subgroup of GABAergic interneurons that coexpress calbindin and in half of the cases parvalbumin. In the thalamus, virtually all reticular nucleus (RTN) neurons were immunopositive for Ca(v)3.3, while neurons in dorsal thalamic nuclei were nonimmunoreactive. At the electron microscopic (EM) level, in cortical layers IV-V and RTN neurons, Ca(v)3.3 immunoreactivity was mainly associated with membranes of dendrites but with some localization in cytoplasm. None was found in axon terminals. In cortex, approximate to 73% of immunogold particles were present in close proximity to synaptic contacts (< 0.5 mu m from the postsynaptic density), while 27% were distributed along membranes at extrasynaptic sites (> 0.5 mu m from the postsynaptic density). In RTN, approximate to 57% particles were evenly distributed along perisynaptic membranes and the remaining 43% of particles were diffusely localized at extrasynaptic membranes. The density of particles along the dendritic membranes of cortical neurons was 40% higher than in RTN neurons. These results suggest that Ca(v)3.3 plays a role in regulating GABAergic neurons whose actions underlie thalamocortical rhythmicity. J. Comp. Neurol. 519: 1181-1195, 2011. (C) 2010 Wiley-Liss, Inc.