Résumé
Objective To explore the role and mechanisms of 5-HT1Areceptors in the medial septum-diagonal band of Broca complex (MS-DB) in hemiparkinsonian rats. Methods Combined behavioral and electrophysiological studies were performed to assess the role of MS-DB 5-HT1Areceptors in working memory and hippocampal theta rhythm in rats with 6-hydroxydopamine (6-OHDA)lesions in the medial forebrain bundle (MFB).Results ① MFB lesions in the rats decreased choice accuracy in the T-maze rewarded alternation test. Intra-MS-DB injection of 5-HT1Areceptor agonist 8-OH-DPAT further decreased choice accuracy,while intra-MS-DB injection of 5-HT1Areceptor antagonist WAY-100635 increased choice accuracy in the lesioned rats.② MFB lesions in the rats decreased peak theta rhythm frequency. Intra-MS-DB injection of 8-OH-DPAT suppressed hippocampal theta rhythm and decreased normalized theta power,while intra-MS-DB injection of WAY-100635 induced theta rhythm and increased normalized theta power.Conclusion Blockade of MS-DB 5-HT1Areceptors can recover cognitive dysfunction in Parkinson's disease, which may be attributed to the enhancement of hippocampal theta rhythm.
Résumé
The distribution relationships of gonadotropin-releasing hormone (GnRH) (5-HT), tyrosine hydroxylase (TH), neurophysin (NP) and ?-endorphin (?-END) in the diagonal band of Broca (DBB) of rat brain were studied by immunohis- tochemistry. The results indicate that there was a close spatial overlap in the distribution between 5HT,TH,NP,?-END fibers and GnRH perikarya and fibers in the ventromedial area of VDBB and dorsomedial area of HDBB. In the dorsomedial area of VDBB close overlap in the distribution between 5-HT fibers and GnRH neurons was also observed. In addition, some TH and NP immunoreactive neurons were found in the medial areas of VDBB and HDBB, The close relationships in distribution and functional significance of GnRH,5-HT, TH, NP and ?-END were discussed.