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[Antidepressant effect of microinjection of neuropeptide Y into the hippocampus is mediated by decreased expression of nitric oxide synthase.] [Ariticle in Chinese]

LIAN Ting, AN Shu-Cheng^*

College of Life Science, Shaanxi Normal University, Xi'an 710062, China

Abstract

Accumulating evidence indicates an important role of hippocampal dendrite atrophy in the development of depression, whileneuropeptide Y (NPY) participates in hippocampal dendrite growth. The present study was aimed to investigate the relationshipbetween NPY and nitric oxide synthase (NOS) in chronic unpredictable mild stress (CUMS)-induced depression. CUMS-induceddepression model was established in Sprague-Dawley rats. Intrahippocampal microinjections of NPY, NPY-Y1 receptor antagonistGR231118 and non-specific NOS inhibitor N-nitro-L-arginine methyl ester (L-NAME) were respectively adopted by rat brainstereotaxic coordinates. The behavioral observations were conducted by sucrose consumption test, open field test and forced swimmingtest. The expressions of NPY, neuronal nitric oxide synthase (nNOS) and inducible nitric oxide synthase (iNOS) in hippocampuswere detected by immunohistochemistry. The results showed that, compared with the control group, rats receiving CUMS for 21 d orintrahippocampal microinjection of GR231118 showed a significant reduction in body weight and depression-like behavior, whichincluded reductions in sucrose preference, locomotor activity, rearing and grooming in open field test, and increased duration ofimmobility in forced swimming test. Moreover, the expression of NPY significantly decreased (P<0.01), while the expressions ofnNOS and iNOS increased obviously in the hippocampal dentate gyrus (DG) and CA3 regions (P<0.01). Intrahippocampal microinjectionsof NPY prevented the depression-like behavioral changes induced by CUMS and decreased the expressions of nNOS and iNOS

Key words: depression; hippocampus; chronic unpredictable mild stress; neuropeptide Y; nitric oxide synthase

Received: 2010-02-02　　Accepted: 2010-04-16

Corresponding author: 安书成　　E-mail: shuchengan@snnu.edu.cn

Citing This Article：

LIAN Ting, AN Shu-Cheng. [Antidepressant effect of microinjection of neuropeptide Y into the hippocampus is mediated by decreased expression of nitric oxide synthase.] [Ariticle in Chinese] . Acta Physiol Sin 2010; 62 (3): 237-246 (in Chinese with English abstract).