Abstract
Tissue fragments of the ventral globus pallidus (VP), presumed to contain a number of cholinergic neurons, from fetal rats (18 days of gestation) were transplanted into the lateral ventricle or the neocortex of adult male rats. Three weeks after transplantatin, the brains of the recipients were removed and stained with cresylviolet to verify the survival and location of the transplants. To determine if cholinergic neurons developed in the grafted VP, the grafted neural tissues were examined histochemically and immunohistochemically for acetylcholinesterase (AchE) and choline acetyltransferase (ChAT) respectively. All of the transplants showed an appearance similar to that of normal neural tissue. A number of AchE-positive and/or ChAT-positive neurons were found in the transplanted VP. In the ChAT immunohistochemical study using a monoclonal antibody, the size of the ChAT-positive neuronal cell bodies in the VP grafts was not significantly different from that of the ChAT-positive neurons in the host VP. The shape of these neurons in the grafts was similar to that of the host ChAT-positive neurons in the VP. Several nervefibers of ChAT-positive neurons in the grafts extended into the host brain tissue, suggesting a possible interaction between the host and the tranplants.
In the human brain, a severe loss of cholinergic neurons in the nucleus basalis of Meynert (corresponding to the VP in the rat) may be closely associated with the occurrence of Alzheimer's disease. Therefore, the functional reconstruction of the cholinergic input into the cortex by transplantation provides a useful tool for understanding the functions of the nbM-cortex pathway and the etiology of the disease.
