The Effects of An Acute Physiological Stressor on Behaviors,Protein Levels and Phosphorylation of Neurogranin in Rats
急性生理应激对大鼠的行为及脑神经颗粒素磷酸化水平的影响

The possible role of brain-specific protein in mediating stress-induced behavioral disorder has gained more and more attention.Neurogranin is a brain-specific protein newly found,which is Ca2 sensitive/calmodulin-binding protein kinase C substrate,and is involved in the process of signaling conduction and long-term potentiation.It is mainly distributed in the frontal cortex,hippocampus and amygdala of rodents that are considered essential components of neural circuitry mediating stress responses.NG knockout animals exhibited deficits in learning and memory.These results implied that NG might be a mediator between stress and behavior.Studies concerning the relations between neurogranin,stress and behavior can provide further information about the mechanisms underlying the effects of stress on behavior.The aim of the present study was to investigate the effects of acute physiological stress on behavior and protein levels of neurogranin in brain,and the correlation between protein levels of neurogranin and stress-induced behavioral changes.Forty rats were randomly divided into swimming stressed group 1(SS1),swimming stressed group 2(SS2),handled-control 1(C1)and handled-control 2(C2),with ten in each.The forced cold-water swimming was used as a physiological stressor.Behavioral changes in rats after stress were observed by open-field test and elevated plus maze task,and protein levels and phosphorylation of neurogranin of hippocampus and forebrain were determined by Western blotting.The results showed that freezing in open-field test in SS1 was more increased than that in C1 group(p<0.01).Protein levels and phosphorylation of neurogranin of hippocampus in SS1 were significantly higher than that in C1(p<0.05,p<0.05)and C2(p<0.05,p<0.05).Protein levels of neurogranin of forebrain in SS1 were significantly higher than that in C1(p<0.01)and C2(p<0.01).Phosphorylation of neurogranin of forebrain in SS1 was significantly higher than that in C1(p<0.01).Correlation is significant at p<0.05 level between freezing and phosphorylation of neurogranin in forebrain.These results suggest that acute swimming stress can induce anxiety.Freezing may be a sensitive behavioral index,and phosphorylation of neurogranin in forebrain may be an effective biological predictor for anxiety and/or depression induced by acute physiological stress.