Secor A, Nocera R, Pang KCH (1999) GABAergic septohippocampal neurons are not necessary for spatial memory. (Poster). Neuroscience 1999 Abstracts 559.9 . Society for Neuroscience, Miami, FL.
Summary: The medial septum/diagonal band of Broca (MS-DB) provides a major input to the hippocampus, and nonselective lesions of MS-DB neurons or their projections to the hippocampus impair spatial memory on several tasks. Two MS-DB cell types project to the hippocampus, the cholinergic and GABAergic neurons. Performance on several spatial memory tasks is less severely affected by selective lesions of the cholinergic MS-DB neurons with 192-IgG saporin (SAP) than by nonselective MS-DB lesions. These results indicate a possible important role of GABAergic septohippocampal (SH) neurons in spatial memory. The present study examined the importance of the GABA SH neurons in spatial memory. GABA SH neurons were destroyed by kainic acid (KA) administration to the MS-DB. Female Sprague- Dawley rats were treated with saline, KA, 192-IgG saporin (SAP) or a combination of both (KA/SAP). After a two-week recovery period, rats were tested on an 8-arm radial maze and a water maze. Immunocytochemistry was performed to verify the lesions. KA (1 µg/µll) produced a nearly complete lesion of parvalbumin immunoreative GABA SH neurons. This dose of KA did not significantly reduce the number of cholinergic neurons. SAP eliminated all cholinergic neurons and the combination KA/SAP produced general degeneration and tissue shrinkage not seen following KA or SAP alone. Acquisition of the 8-arm radial maze task and performance of a delay version of the task were not altered by KA alone or SAP alone, but were significantly impaired by KA/SAP. Acquisition of the water maze task was not significantly affected by KA, but was slightly impaired by SAP and severely impaired by KA/SAP. These results demonstrate that GABA SH neurons are not necessary for spatial memory. The possible interaction between GABA and cholinergic SH neurons will be explored. Supported by NS35389 and AG16093.
Related Products: 192-IgG-SAP (Cat. #IT-01)