Alterations of nAChRs and ERK1/2 in the brains of rats with chronic fluorosis and their connections with the decreased capacity of learning and memory.
In order to reveal the mechanism of the decreased ability of learning and memory induced by chronic fluorosis, nicotinic acetylcholine receptors (nAChRs) and the pathway of extracellular signal regulated protein kinase (ERK1/2) were investigated by using the rats fed with different concentrations of sodium fluoride for 6 months. Spatial learning and memory of the rats were evaluated by Morris Water Maze test. The expressions of nAChRs, ERK1/2 and mitogen-induced extracellular kinase (MEK1/2) at protein and mRNA levels were detected by Western blotting and real-time PCR, respectively. The results showed that as compared with controls, the learning and memory capacity in the rats with fluorosis was decreased. The protein expressions of alpha7 and alpha4 nAChR subunits in rat brains with fluorosis were decreased by 35% and 33%, whereas the corresponding receptor subunit mRNAs did not exhibit any changes. The increases of phospho- and total-ERK1/2 as well as phospho-MEK1/2 at the protein levels were found in the brains of rats with fluorosis as compared to controls, and no difference of ERK1/2 mRNA was found. In addition, the activation rate of phospho-ERK1/2 was decreased in the brains affected with fluorosis. The modifications of nAChRs and ERK1/2 pathway might be connected with the molecular mechanisms in the decreased capacity of learning and memory of the rats with fluorosis.
Liu
Yan-Jie
YJ
Department of Pathology and Molecular and Biology, Guiyang Medical College, Guiyang, PR China.
Gao
Qin
Q
Wu
Chang-Xue
CX
Guan
Zhi-Zhong
ZZ
D000818:Animals; D015153:Blotting, Western; D001923:Brain Chemistry / Q000187:drug effects*; D005260:Female; D008297:Male; D018782:Maze Learning / Q000187:drug effects*; D008568:Memory / Q000187:drug effects*; D019950:Mitogen-Activated Protein Kinase 1 / Q000032:analysis* / Q000096:biosynthesis; D048052:Mitogen-Activated Protein Kinase 3 / Q000032:analysis* / Q000096:biosynthesis; D016133:Polymerase Chain Reaction; D051381:Rats; D017207:Rats, Sprague-Dawley; D011978:Receptors, Nicotinic / Q000032:analysis* / Q000096:biosynthesis; D012969:Sodium Fluoride / Q000009:adverse effects*; D064569:alpha7 Nicotinic Acetylcholine Receptor
D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D011978:Receptors, Nicotinic; D012969:Sodium Fluoride; D064569:alpha7 Nicotinic Acetylcholine Receptor; C579165:Chrna7 protein, rat