| Habenula nucleus (Hb) was known as an important connective hub ofLimbic system of forebrain and Midbrain&Brainstem. It involved in variousfunctional activities of Central nerve system (CNS) through complicate fiberprojections and neurotransmitters. Recently, Hb was believed to play a key rolein cognitive functions. However, its mechanism was still not very clear.Objective：This study was designed to observe the micro-changes of DA&Achsystem in Hb-destroyed rats. The purpose of this study was to inquire thepossible pathways and mechanisms of Hb’s involvement in cognitive functions.Hence, this study might provide new evidences for diagnosis and treatment ofclinical cognitive disorders.Method：There are3groups: Control group, Sham group, and Hb-destroyed group.Behavioral changes were observed by Morris water maze test;acetylcholinesterase (AchE) in cerebrospinal fluid (CSF) and hippocampus, aswell as the changes of dopamine (DA) in the CSF and substantia nigra weremeasured by ELISA assay; expression of choline acetyltransferase (ChAT) inhippocampus and tyrosine hydrogenase (TH) in substantia nigra were evaluatedby immunohistochemical staining.Result：Results of this study showed:(1) Behavioral changes: In place navigationtest, there was no difference between Control group and Sham group (P>0.05); compared with the Control group and Sham group, latency to find the hiddenplatform of Hb-detroyed group rats was prolonged and there was a significantstatistical difference (P<0.01). In spatial probe test, there was no difference oftimes of reaching the place of hidden platform in100s between Control groupand Sham group (P>0.05); compared with the Control group and Sham group,times of reaching the place of hidden platform in100s of Hb-destroyed grouprats decreased obviously and there was a significant statistical difference(P<0.01).(2) Content changes of AchE and DA: In Hb-destroyed rats, thecontent of AchE in CSF decreased significantly (P<0.01), but there was nochanges in hippocampus (P>0.05); the content of DA in substantia nigraincreased obviously (P<0.05), but there was no changes in CSF (P>0.05).(3)Positive cell counts of ChAT and TH: In Hb-destroyed rats, positive cell countsof ChAT in hippocampus appeared no changes (P>0.05) and TH in substantianigra increased significantly (P<0.01).Conclusion:This study concluded:(1) Hb lesions induced an obvious decrease inlearning abilities of spatial memory and probe and it indicated that Hb wasinvolved in modulation of cognition in CNS.(2) Hb lesions induced a decreaseof AchE in CSF, and there was no changes of AchE and ChAT in hippocampus.It indicated that Hb took part in release of Ach in CNS, but it had no effects oncontent of Ach in hippocampus.(3) Hb lesions induced an increase of DA andTH in substantia nigra. It indicated that Hb played a role in release andtransportation of DA in substantia nigra. |
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