强迫游泳大鼠脑内信号分子ERK1/2磷酸化水平的变化

CHANGES OF EXPRESSION OF PHOSPHORYLATED ERK1/2 IN THE RAT BRAIN INDUCED BY FORCED SWIMMING

通过观察强迫游泳时大鼠脑内不同核团内ERK1/2磷酸化水平变化,探讨与负性心理应激有关的脑内环路。将大鼠置于高60cm、水深约30cm的玻璃缸内,先预游15min,24h后进行5min的强迫游泳,观察大鼠游泳过程中的不动时间。游泳完毕后将大鼠灌流处死,对全脑组织进行磷酸化ERK1/2(pERK1/2)的免疫组织化学染色及其与酪氨酸羟化酶(TH)在部分核团内的免疫荧光双标细胞。强迫游泳后前额叶皮质、外侧隔区、下丘脑室旁核、海马CA13区、杏仁内侧亚核和皮质亚核、孤束核等脑区/核团中pERK1/2阳性细胞数显著增多;而杏仁中央亚核、下丘脑视上核内的磷酸化ERK1/2蛋白水平下降,阳性细胞数明显减少。免疫荧光双标结果表明,孤束核内部分pERK1/2阳性细胞呈TH免疫反应阳性。上述结果表明,以上脑区/核团内的神经元可能和负性心理应激的中枢调控有关,ERK1/2信号通路参与了其调控过程。此外,孤束核中的儿茶酚胺能神经元可能参与了心理应激的脑内活动。

In order to outline the neuronal circuit in the brain related to the modulation of negative psychological stress, the changes of expression of phosphorylatod ERK1/2 （pERK1/2） in the rat brain induced by forced swimming was observed. In the first experimental day the rats were placed in a glass tank filled with warm water and forced swimming for 15 min. The tank was 60 cm in height and the water in it was 30 cm in depth. After an interval of 24 h the rats were forced to swim again for 5 min and the immobility time was recorded during the test session. All rats were sacrificed with a perfusion of 4% paraformaldehyde immediately after the termination of the test and the animals without experience of swimming were also perfused with the same procedure to serve as control, lmmunohistochemical ABC and double immunofluorescence staining methods were used to observe the distribution of pERK1/2 - like immunoreactive （LI） neurons in whole brain and the coexistence of TH and pERK1/2 in part of the brain area. The number of pERK1/2 - L1 neurons was greatly increased in prefrontal cortex （ PFC）, hypothalamic paraventricular nucleus （ PVN ）, CA1-3 areas of hippocampus, medial subnucleus of amygdala （ MeA）, cortical area of amygdala （CoA） ,lateral septum （LS） as well as nucleus of solitary tract （NTS） ,while the normally expressed pERK1/2 in the neurons of central subnucleus of amygdala （CeA） and supraotic nucleus （ SON ） was obviously inhibited where the number of pERK1/ 2-LI neurons decreased significantly. Double immunofluorescent staining result showed that part of pERK1/2-LI neurons in NTS also stained for tyrosine hytroxylase （TH）, an enzyme responsible for the synthesis of catecholamine. The present results indicate that the neurons in above-mentioned brain areas/nuclei might be responsible for the modulation of negative psychological stress and ERK1/2 pathway possibly plays a role in this process. In addition,the catecholaminergic neurons in NTS seem to involve in psychological stress.