The overall aim of the proposed studies is to further elucidate the ultrastructural neurochemical anatomy and interconnections of the septo- hippocampal complex. These studies will aid our understanding of mnemonic functions and human diseases, particularly Alzheimer's disease and temporal lobe epilepsy. Additional analyses of the intrinsic and extrinsic connections of the sexually dimorphic and estrogen/androgen sensitive septal complex, particularly with the syndrome and in understanding how the neuroendocrine and cognitive/associational areas of the central nervous system interact. While there are major differences between the human and rodent hippocampal formations, these structures are very similar in the human and monkey brain. Therefore, in addition to rat studies, we propose to continue the analysis of the hippocampal formation of subhuman primates. Two major lines of inquiry are proposed: a) why some hippocampal neurons and areas are more seizure sensitive than others; and b) how the septal complex mediates bidirectional information between the hippocampus and the neuroendocrine hypothalamus. By using interlinked state-of-the-art morphological techniques, including correlated light and electron microscopic double immunostaining methods, antero and retrograde tracer techniques, and Golgi impregnation, as well as by combining electrophysiological and histochemical methods, the following studies are suggested: 1. Further analysis of the synaptology and transmitter content of seizure-sensitive and seizure-resistant neurons in the rat and monkey hippocampal formation. 2. Neurochemistry of interneurons associated with identified mossy cells. 3. Further characterization of extrinsic hippocampal substance P and calretinin systems. 4. Synaptology and neurochemistry of subcortical circuitries controlling septal area neurons and the septo-hippocampal pathway.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
2R01NS026068-05
Application #
3411678
Study Section
Neurology B Subcommittee 2 (NEUB)
Project Start
1988-12-01
Project End
1997-11-30
Budget Start
1992-12-01
Budget End
1993-11-30
Support Year
5
Fiscal Year
1993
Total Cost
Indirect Cost
Name
Yale University
Department
Type
Schools of Medicine
DUNS #
082359691
City
New Haven
State
CT
Country
United States
Zip Code
06520
Leranth, C; Shanabrough, M; Horvath, T L (2000) Hormonal regulation of hippocampal spine synapse density involves subcortical mediation. Neuroscience 101:349-56
Wu, M; Shanabrough, M; Leranth, C et al. (2000) Cholinergic excitation of septohippocampal GABA but not cholinergic neurons: implications for learning and memory. J Neurosci 20:3900-8
Alreja, M; Wu, M; Liu, W et al. (2000) Muscarinic tone sustains impulse flow in the septohippocampal GABA but not cholinergic pathway: implications for learning and memory. J Neurosci 20:8103-10
Alreja, M; Shanabrough, M; Liu, W et al. (2000) Opioids suppress IPSCs in neurons of the rat medial septum/diagonal band of Broca: involvement of mu-opioid receptors and septohippocampal GABAergic neurons. J Neurosci 20:1179-89
Leranth, C; Carpi, D; Buzsaki, G et al. (1999) The entorhino-septo-supramammillary nucleus connection in the rat: morphological basis of a feedback mechanism regulating hippocampal theta rhythm. Neuroscience 88:701-18
Leranth, C; Vertes, R P (1999) Median raphe serotonergic innervation of medial septum/diagonal band of broca (MSDB) parvalbumin-containing neurons: possible involvement of the MSDB in the desynchronization of the hippocampal EEG. J Comp Neurol 410:586-98
Leranth, C; Shanabrough, M; Horvath, T L (1999) Estrogen receptor-alpha in the raphe serotonergic and supramammillary area calretinin-containing neurons of the female rat. Exp Brain Res 128:417-20
Holderith, N; Varoqueaux, F; Borhegyi, Z et al. (1998) Dual (excitatory and inhibitory) calretinin innervation of AMPA receptor-containing neurons in the rat lateral septum. Exp Brain Res 119:65-72
Leranth, C; Sladek Jr, J R; Roth, R H et al. (1998) Efferent synaptic connections of dopaminergic neurons grafted into the caudate nucleus of experimentally induced parkinsonian monkeys are different from those of control animals. Exp Brain Res 123:323-33
Borhegyi, Z; Leranth, C (1997) Substance P innervation of the rat hippocampal formation. J Comp Neurol 384:41-58

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