title: Effects of high-speed railway noise on the synaptic ultrastructure and phosphorylated-CaMKII expression in the central nervous system of SD rats.
abstract: To investigate the toxic effects of high-speed railway noise on learning and memory function, Sprague-Dawley (SD) rats were exposed to high-speed railway noise for 90 days. The noise was recorded from an actual environment and adjusted to a day-night equivalent continuous A-weighted sound pressure level (L(dn)) of 70dB(A). Transmission electron microscopy (TEM) and Western blot analysis were used to observe the synaptic ultrastructure and detect the level of phosphorylated-Ca(2+)/calmodulin-dependent protein kinase II (p-CaMKII), respectively, in the hippocampus, temporal lobe and amygdala. Compared with the sham control group, the results of the TEM showed that the width of the noise model group's synaptic cleft increased markedly in the hippocampus, amygdala (P<0.05) and temporal lobe (P<0.01); the thickness of postsynaptic density (PSD) decreased significantly (P<0.01). The results of the TEM suggest that the synaptic plasticity of structure and function were abnormal and that this abnormality resulted in a reduction in synaptic transmission efficiency. This reduction may have led to dysfunctions in learning and memory. Additionally, the Western blot analyses revealed that the level of p-CaMKII decreased significantly in the temporal lobe of the noise model group compared with the sham control group (P<0.05). The results of the Western blot analysis indicate a reduction in synaptic transmission efficiency, which resulted in impairments in learning and memory function in the temporal lobe. Both of the above conclusions are consistent with each other.
authors.affiliation: Institute of Environmental Pollution & Control Technology, Nongshenghuan Building B388, Zijingang Campus, Zhejiang University, Yuhangtang Road 866, Hangzhou, Zhejiang Province, China. dgq@zju.edu.cn
authors.forename: Guoqing
authors.initials: G
authors.lastname: Di
authors.forename: Yue
authors.initials: Y
authors.lastname: Zheng
mesh_terms: D000818:Animals; D001921:Brain / Q000201:enzymology / Q000648:ultrastructure*; D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2 / Q000378:metabolism*; D007858:Learning / Q000502:physiology*; D008297:Male; D008568:Memory / Q000502:physiology*; D046529:Microscopy, Electron, Transmission; D009624:Noise, Transportation / Q000009:adverse effects*; D010766:Phosphorylation / Q000187:drug effects; D011890:Railroads; D051381:Rats; D017207:Rats, Sprague-Dawley; D013569:Synapses / Q000648:ultrastructure
chemical_list: D054732:Calcium-Calmodulin-Dependent Protein Kinase Type 2