He Xiao-fei, Lan Yue, Zhang Qun, Liang Feng-yin, Luo Chuan-ming, Xu Guang-qing, Pei Zhong
Department of Rehabilitation Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China.
Department of Rehabilitation Medicine, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China.
Physiol Behav. 2015 Nov 1;151:502-8. doi: 10.1016/j.physbeh.2015.08.026. Epub 2015 Aug 25.
In the current study we investigated the role of the corpus callosum, particularly the gamma-aminobutyric acid-ergic (GABAergic) projection neurons involved in interhemispheric inhibition (IHI). In order to explore IHI in primary visual cortices, we adopted a protocol whereby we performed a direct current lesion of the unilateral primary visual cortex with or without posterior callosotomy, and used two-photon Ca(2+)in vivo imaging on the opposite unaffected region to detect neural activities in mice. Following this procedure, the numbers of vesicular GABAergic transporters (VGATs) and GABAergic interneurons in the unaffected primary cortex were determined using immunofluorescence staining. Results indicated that following unilateral visual cortical lesioning without callosotomy, the neuronal Ca(2+) activities in the opposite side were significantly increased. However, the neuronal activities of the unaffected visual cortex in animals with unilateral cortical lesion with callosotomy were not significantly different. Additionally, there was no significant difference in the numbers of GABAergic interneurons in the unaffected region between each group, while the number of VGATs in the unaffected region was significantly decreased following unilateral visual cortical lesion without callosotomy, which was unchanged once with callosotomy. Finally, callosotomy alone without cortical lesioning produced no change in neuronal activities, the number of GABAergic interneurons or VGATs. Our results demonstrate that IHI between the homologous primary visual cortices occurs via the corpus callosum, and further indicate the important involvement of long-range GABAergic interneurons in transcallosal inhibition.
在当前研究中，我们调查了胼胝体的作用，特别是参与半球间抑制（IHI）的γ-氨基丁酸能（GABA能）投射神经元的作用。为了探究初级视觉皮层中的IHI，我们采用了一种实验方案，即对单侧初级视觉皮层进行直流电损伤，同时进行或不进行后胼胝体切开术，并在对侧未受影响区域使用双光子Ca(2+)活体成像来检测小鼠的神经活动。按照此程序，使用免疫荧光染色确定未受影响的初级皮层中囊泡GABA能转运体（VGATs）和GABA能中间神经元的数量。结果表明，在未进行胼胝体切开术的单侧视觉皮层损伤后，对侧的神经元Ca(2+)活性显著增加。然而，进行了胼胝体切开术的单侧皮层损伤动物中，未受影响的视觉皮层的神经元活动没有显著差异。此外，每组未受影响区域的GABA能中间神经元数量没有显著差异，而在未进行胼胝体切开术的单侧视觉皮层损伤后，未受影响区域的VGATs数量显著减少，进行胼胝体切开术后则没有变化。最后，仅进行胼胝体切开术而无皮层损伤，神经元活动、GABA能中间神经元数量或VGATs均未发生变化。我们的结果表明，同源初级视觉皮层之间的IHI通过胼胝体发生，并进一步表明远程GABA能中间神经元在胼胝体间抑制中具有重要作用。
