Innervation of the ovary in amphioxus: ultrastructural and immunohistochemical study

The distribution of unmyelinated nerve fiber in the ovary of amphioxus was found with transmission electron microscopic technique for the first time. The fiber is located under the ovary coat, and in close contact with it. There are two types of synaptic vesicles in the terminals of nerve fiber: one is dense-cored vesicle, the other is clear vesicle. In addition, the nerve terminals contact with follicle cells of ovary can be seen. Using immunohistochemical method, it is further demonstrated that the unmyelinated nerve fiber may be a noradrenergic nerve fiber which is located on the ovary coat and follicle cell.