Septohippocampal Nucleus


The obtained results revealed that the neuronal activation occurring 3 h before the expected meal was not confined to one brain structure, but was evident in the anterior hippocampal continuation and septohippocampal nucleus (AH/SHi), the anterior part of the paraventricular thalamic nucleus (PVTa), and the dorsomedial hypothalamic nucleus (DMH), thus representing distributed septohippocampal-thalamo-hypothalamic circuitry that may act as the FEO.  

High-density specific binding was found in discrete areas of the brain and spinal cord, namely in the limbic system (hippocampal formation, septohippocampal nucleus, indusium griseum, hypothalamus, amygdaloid nuclei), superior colliculus, dorsal raphé, and substantia gelatinosa of the spinal cord.  

Other fibers entered the diagonal band of Broca and formed a dense plexus of labeled fibers in the dorsal half of the intermediate portion of the lateral septal nucleus and the septohippocampal nucleus.  

Additional HCt efferents are directed to the subcallosal septum (presumed septohippocampal nucleus), the olfactory tubercle and the islands of Calleja.  

The most intense signals were observed in the ependymal cell layer along the wall of the third ventricle in the hypothalamus, CA1 region of the hippocampus, indusium griseum and septohippocampal nucleus.  

In adult rats, both a single administration or seven daily injections of Neotrofin at 10, 30 or 100 mg/kg intraperitoneally increased HO-1 immunoreactivity in neurons of the hippocampal formation and its connections including CA1-4, fornix, septal nuclei, hippocampal commissure, septohippocampal nucleus, fimbria, anteroventral thalamic nucleus, frontal and parietal cortex.  

Inhibition of behavioral signs of naloxone-precipitated morphine withdrawal was accompanied by significantly reduced c-fos expression in the locus coeruleus, lateral septal nucleus, ventral part of the periaqueductal grey, cingulate and frontal cortices, and septohippocampal nucleus.  

Chronic ethanol consumption decreased binding of (S)-[ 3H]5-fluorowillardiine in four cortical regions (frontal, parietal, occipital and temporal cortex), hippocampus and septohippocampal nucleus. In contrast, ethanol withdrawal induced a significant "rebound" increase in binding by +22% in frontal and parietal cortex, by +17% in cingulate cortex and +13% in claustrum, and by +14% in the septohippocampal nucleus compared to chronic ethanol-exposed FH rats.  

For example, in adult NT-3(lacZneo)/+ mice, beta-galactosidase is expressed in high amounts in limbic areas of the cortex (cingulate, retrosplenial, piriform, and entorhinal), in the visual cortex, in the hippocampal formation (dentate granule cells, CA2 cells, fasciola cinereum, induseum griseum, tenia tecta, presubiculum, and parasubiculum), and in the septum (septohippocampal nucleus and lateral dorsal septum).  

Considering both the density of labeled neurons per region and their intensity of labeling, the distribution of prepronociceptin messenger RNA-containing neurons can be summarized as follows: the highest level of prepronociceptin messenger RNA expression was detected in the septohippocampal nucleus, bed nucleus of the stria terminalis, central amygdaloid nucleus, and in selective thalamic nuclei such as the parafascicular, reticular, ventral lateral geniculate and zona incerta.  

Autoradiographic mapping of 5-HT1A receptors in SFV-infected brain showed substantially higher binding in nucleus accumbens, tenia tecta, septohippocampal nucleus, septum, medial and basolateral amygdaloid nucleus, anterioventral preoptic nucleus, hippocampus, interpeduncular nucleus, frontal, lateral orbital, and entorhinal cortex and claustrum on days 6 and 14.  

No significant difference in the binding of [ 3H]ketanserin was found in frontal, parietal, agranular insular, and piriform cortices, caudate-putamen, olfactory tubercle, nucleus accumbens, thalamus, septohippocampal nucleus, and claustrum.  

Additional labeled perikarya were also detected in the glomerular layer of the olfactory bulb; tenia tecta; anterior septum; bed nucleus of the stria terminalis; medial, basolateral and cortical nuclei of the amygdala; cerebral and entorhinal cortex; the septohippocampal nucleus; Ammon's horn of the hippocampus and the dorsal raphe.  

However, the olfactory bulb, the anterior olfactory nucleus, the islands of Calleja, the CA1-CA3 fields of the hippocampus, the septohippocampal nucleus, the diagonal band of Broca, the basal and cortical amygdaloid nuclei, the entopeduncular nucleus, the subthalamic nucleus, the superior colliculus, the Edinger-Westphal nucleus, the dentate nucleus, the raphes linearis and pontis, the dorsal cochlear nucleus, the medial vestibular nucleus, the inferior olive, and the dorsal motor nucleus of the vagus nerve also contained preprodynorphin messenger RNA-synthesizing perikarya.  

Caudate-putamen, nucleus accumbens, olfactory tubercle and septohippocampal nucleus show a high perinatal maximum.  

Such were the mitral and tufted cells of the olfactory bulb; anterior olfactory nucleus; neocortical regions; cingulate cortex; retrosplenial cortex; piriform cortex; perirhinal cortex; CA1; CA3; granule cells of the dentate gyrus; superficial layers of the subicular cortex; deep layers of the entorhinal, parasubicular, and presubicular cortices; ventral part of the lateral septal nucleus; septohippocampal nucleus; triangular septal nucleus; nuclei of the diagonal band; bed nucleus of the stria terminalis; ventral pallidum; claustrum; amygdaloid nuclei other than the intercalated nuclei; preoptic region; hypothalamic nuclei other than the medial mammillary nucleus; ventral lateral geniculate nucleus; locus coeruleus; Purkinje cells; many nuclei of the lower brainstem other than the superior colliculus, periaqueductal gray, interpeduncular nucleus, pontine nuclei, and dorsal cochlear nucleus; and dorsal horn of the spinal cord.  

Most aromatase-immunoreactive neurons formed two oblique bands in the lateral and the medial zones of the lateral septum; in addition, labeled cells were present in the septohippocampal nucleus and the laterodorsal portion of the bed nucleus of the stria terminalis.  

Selective disruption of septodentate input produced by lesions of the septohippocampal nucleus blocked the effects of systemic ethanol on LTP.  

Thus, a strong signal was observed in the accessory olfactory bulb, the perirhinal sulcus, the ventral aspects of the hippocampal formation, some amygdaloid nuclei, the diagonal band nucleus, parts of nucleus accumbens, the bed nucleus of the stria terminalis, dorsomedial, lateral and perifornical hypothalamic regions, the septohippocampal nucleus, parts of the vestibular complex, as well as many bulbar motoneurons including the facial, dorsal vagal, ambiguus and hypoglossal nuclei, the superficial layer of the spinal trigeminal nucleus, and motoneurons and dorsal horn neurons in the spinal cord.  

In the forebrain, the signals were detected in the olfactory bulb, the endopiriform nucleus, the septohippocampal nucleus, the habenular nuclei, and most of the thalamic nuclei.  

Neuronal populations that showed bFGF immunoreactivity included septohippocampal nucleus, cingulate cortex, subfield CA2 of the hippocampus, cerebellar Purkinje cells, cerebellar deep nuclei, facial nerve nucleus, and the motor and spinal subdivisions of the trigeminal nucleus and facial nerve nucleus.  

The highest levels of binding were seen in the globus pallidus and ventral pallidum followed by the septohippocampal nucleus, anterior pituitary, the CA2 and CA3 region of the hippocampus, ventral pallidum, the molecular layer of the cerebellum and substantia nigra zona reticulata.  

Their density was particularly important in substantia nigra reticulata, septohippocampal nucleus, globus pallidus, neocortex, molecular layer of cerebellum, CA3 field and dentate gyrus of hippocampus.  

The highest density of immunoreactivity was seen in the olfactory bulb, septohippocampal nucleus, indusium griseum, islands of Calleja, intermediate part of the lateral septal nucleus, and Ammon's horn.  

The earliest degeneration was observed at day 1 in the intermediate and ventral divisions of the lateral septal nucleus, followed by development of degeneration on days 2-4 in neuron populations including the septohippocampal nucleus, septohypothalamic nucleus, anterior olfactory nucleus, bed nucleus of the stria terminalis, endopiriform nucleus, parafascicular nucleus, superior colliculus, interstitial nucleus of the posterior commissure, inferior colliculus, pontine nuclei, raphe nuclei, pars caudalis of the spinal trigeminal nucleus, the caudal aspect of nucleus tractus solitarius, dorsal vagal motor nucleus, granule cells in the dentate gyrus, pyramidal cells in CA fields of the hippocampus, and of neurons in the subiculum, pyriform cortex, entorhinal cortex and neocortex (mainly layer Vb and VI).  

Analysis of brain sections stained with gallocyanin or for acetylcholinesterase showed that ibotenic acid produced cell loss in the dorsal lateral septal nucleus and the septohippocampal nucleus.  

Ibotenic acid injections in the septal nuclei of the forebrain produced severe cell loss in the dorsal lateral septal nucleus and the septohippocampal nucleus.  

These included several forebrain regions, such as the superficial layers of the rostral neocortex, dorsal neostriatum, nucleus accumbens, septohippocampal nucleus, intralaminar thalamic nuclei, and external capsules.  

In contrast, nuclei of the septum (diagonal band of Broca, septohippocampal nucleus, dorsal part of the lateral septal nucleus), the rostrodorsal part of the hippocampus and other discrete nuclei [ endopyriform nucleus, anterior cortical amygdaloid nucleus, the vermis columns (9-10), the dorsal tegmental nucleus, the hypoglossal and ambiguus nucleus] had high levels of [ 125I]Bolton and Hunter substance P binding but were only labeled weakly by [ 125I]Bolton and Hunter eledoisin.  


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