Woodruff M L, Baisden R H
Department of Anatomy, Quillen-Dishner College of Medicine, East Tennessee State University, Johnson City 37614.
Neurotoxicol Teratol. 1990 Jan-Feb;12(1):33-9. doi: 10.1016/0892-0362(90)90110-x.
Trimethyltin (TMT) is known to produce substantial damage to the hippocampal formation. It also destroys neurons within the entorhinal cortex, thereby causing degeneration of perforant path afferents that terminate in the outer molecular layer (OML) of the dentate gyrus. Surgical destruction of the entorhinal cortex also causes the perforant path to degenerate. This leads to reactive synaptogenesis (axonal sprouting) of septal afferents to the dentate gyrus. The purpose of the present study was to determine whether administration of 6 mg/kg of TMT by gavage to rats would cause axonal sprouting within the septo-dentate projection. A histochemical stain for acetylcholinesterase (AChE) was used. Compared to control subjects rats given TMT exhibited significantly denser AChE staining in the dentate OML. This is putative indication of reactive synaptogenesis within the cholinergic projection to this layer of the dentate and is somewhat surprising because other neurotoxins, such as lead and ethanol, that affect neurons within the hippocampal formation reduce the capacity for reactive synaptogenesis in response to lesions of the entorhinal cortex.
已知三甲基锡（TMT）会对海马结构造成严重损害。它还会破坏内嗅皮质内的神经元，从而导致终止于齿状回外分子层（OML）的穿通通路传入纤维发生退化。对内嗅皮质进行手术破坏也会导致穿通通路退化。这会导致隔区传入齿状回的纤维发生反应性突触形成（轴突发芽）。本研究的目的是确定通过灌胃给大鼠施用6mg/kg的TMT是否会导致隔-齿状投射内的轴突发芽。使用了乙酰胆碱酯酶（AChE）组织化学染色。与对照大鼠相比，给予TMT的大鼠在齿状回OML中表现出明显更密集的AChE染色。这被认为是胆碱能投射至齿状回该层内反应性突触形成的迹象，并且有点令人惊讶，因为其他影响海马结构内神经元的神经毒素，如铅和乙醇，会降低对内嗅皮质损伤的反应性突触形成能力。
