D. Koczyk

Differential effects of GM1 ganglioside treatment on glial fibrillary acidic protein content in the rat septum and hippocampus after partial interruption of their connections.

Abstract: The glial fibrillary acidic protein (GFAP) content was investigated using immunoblotting techniques in the septum and hippocampus of the rat after bilateral lateral fimbria transection. Seven days after surgery GFAP content increased significantly both in the septum (140% of control) and hippocampus (120% in dorsal, the less denervated, and 145% in the most denervated ventral part), indicating the occurrence of reactive gliosis. The GM1 treatment caused statistically significant attenuation of GFAP increment in all hippocampal parts. In contrast, GM1 treatment has no influence on the increase of GFAP content in the septum. Results suggest a differential effect of GM1 on the two gliotic reactions formed as a consequence of the lesion at the level of the source of innervation (septum) and the target (hippocampus).

Time Course of Trophic Responses of Astrocytes in Rat Hippocampus Induced by Trimethyltin Intoxication: an Immunocytochemical Study

Trimethyltin (TMT), the organometallic compound, has been recognized as a potent environmental neurotoxin (see 1). Behavioral and neuropathological profiles reported in human victims may be reproduced experimentally in TMT intoxicated rats. Although TMT-induced effects are observed in several brain structures, particularly severe consequences have been noticed in the hippocampus. TMT destroys specifically hippocampal CA3/CA4 and CA1 pyramidal cells, sparing the dentate granule cells. Neuronal degeneration is accompanied by intense gliosis (1,2). Because of its distinct pattern of damage TMT intoxication in rat creates a very convenient model to study neuron-glia interactions. In answer to various brain insults astrocytes demonstrate a multitude range of responses including production of several neurotrophic factors (3,4,5). We have recently reported that in TMT intoxicated rats the plastic neuronal changes in the hippocampus are accompanied by induction of astrocytic trophic activity (6). The present study describes the im-munocytochemical data on the time course of astrogliosis and astrocytic trophic responses in the hippocampus evoked by TMT intoxication. The detailed description of spatio-temporal profiles of the changes as revealed both by quantitative and immunocytochemical investigations is reported elsewhere (Oderfeld-Nowak et al., submitted).