Effects of partial lesion of dorsal hippocampal afferent and GM1 ganglioside treatment on conditioned emotional response and hippocampal afferent markers in rats.

Acquisition of the conditioned emotional response (CER) in 32 male hooded rats previously learned to press a bar for food and divided into four groups was studied. Two groups received electrolytic lesions of the dorsal hippocampal afferent and were thereafter injected either with GM1 ganglioside (30 mg/kg daily) or with buffer. Two remaining groups were sham operated and similarly injected.

In vivo activated brain astrocytes may produce and secrete nerve growth factor-like molecules.

The cellular localization of the nerve growth factor-like immunoreactivity (NGF-LIR) has been studied in the septum and hippocampus of the rat brain 7 days following partial electrolytic lesion (2 mA, 30 s) of the septohippocampal pathways or after single intraventricular administration of 15 U of interleukin-1 beta (IL-1 beta). A double immunostaining technique which allowed a simultaneous localization of NGF-LIR and that of astroglia marker glial fibrillary acidic protein was used. Our data show that after both treatments, apart from neuronal localization of NGF-LIR typical for normal brain, many astrocytes both in the septum and hippocampus became NGF-like immunoreactive.

Derivatives of ganglioside GM1 as neuronotrophic agents: comparison of in vivo and in vitro effects.

Exogenously administered gangliosides have been shown to behave as neuronotrophic/neuritogenic agents in a variety of cell culture systems and animal models, but it is not known whether they operate by the same mechanism in vivo and in vitro. To probe this question we have employed two derivatives of GM1 lacking the negative charge: the methyl ester (GM1-CH3) and the NaBH4 reduction product of the latter (GM1-OH) in which the carboxyl group is replaced by a primary alcohol. Both derivatives proved to be as neuritogenic as GM1 in 3 cell culture systems: neuro-2A cels, PC12 cells and explanted dorsal root ganglia.

Early changes in ornithine decarboxylase activity in a partially denervated hippocampus of rats untreated and treated with GM1 ganglioside.

Bilateral transection of the lateral fimbria, which disrupts partially the septo-hippocampal projections and results in partial hippocampal denervation, produced a significant increase in the ornithine decarboxylase (ODC) activity in the hippocampus. An increase occurred already 0.5 h after the operation and the activity remained intensified for at least 22 h after injury.

Nerve growth factor induces a dose-dependent and long-lasting increase of choline acetyltransferase activity in the septal area and hippocampus of uninjured rats.

The effect of nerve growth factor (NGF) on the intact septohippocampal cholinergic system of adult rats was studied. Nerve growth factor was continuously infused at different doses (5-100 micrograms) for two weeks into the lateral ventricle of adult rats. Controls received intracerebroventricular infusion of equal amounts of cytochrome c.