Normal SD rats were stimulated for a period of time with electro-acupuncture and then were killed. The ventral mesencephalic regions of the rats were excavated to prepare the crude extracts

which

afterwards

were added into the primary mesencephalic neurons in culture. An immunocytochemical staining was performed to detect the dopaminergic neuron on the 5th and the 10th day respectively in vitro

and the average expression number of the positive neurons in each well was counted

the diameter of the cell body and the length of the neurite were measured in each group. The results indicated that the crude extracts made from the ventral mesencephalic regions of rats stimulated with electro-acupuncture could promote the development of cell body and the growth of the neurite but had no effect on the expression number of dopaminergic neurons. It is suggested that the results might be probably related to the effect of electro-acupuncture in stimulating the release or secretion of some potential neurotrophic factors in the ventral mesencephalic region.