[Morphological effects of ammonia on cultured fetal rat neurons]

The effects of ammonia on cultured fetal rat neurons and the possible relation between morphologic changes of neurons and the pathogenesis of hepatic encephalopathy were studied on dissociated fetal rat neuronal cultures, using light microscopy, transmission electron microscopy and immunohistochemistry methods. The neurons exhibited cellular swelling, chromatolysis, vacuolization and granulation, followed by segmental enlargement and fragmentation of cellular processes, detachment of neurons with pyknotic nuclei. Electron microscopic examination displayed dilation of mitochondria and endoplasmic reticulum, degranulation of rough endoplasmic reticulum, accumulation of dense bodies together with swelling of the process with loss of neurofilaments. The expression of neurofilament and synaptophysin became weak and even negative. The data therefore suggests that ammonia may exert a toxic effect on cultured neurons, disturbing their normal function and facilitating the development of hepatic encephalopathy.