Development of .GAMMA.-enolase immunoreactive cells in the nervous system of human embryos.

Abstract
The development of .gamma.-enolase immunoreactive cells in five human embryos (Carnegie stages: 13-16 and 21; crown-rump length: 6.3-23.4 mm) was investigated by immunohistochemistry, using the basal plate of the neural tube, dorsal root ganglion at the cervical level, trigeminal and vestibulocochlear ganglia, and para-esophageal and para-tracheal ganglia. In the basal plate of the stage 13 embryo, not only the motor neurons but also the anterior root was immunoreactive at the level of the cervical spinal cord. Some of these reactive neurons were in the rhombencephalon. The motor neurons in the basal plate of mesencephalon and thoracic spinal cord of the stage 14 embryo were immunoreactive, while those of the lumbar spinal cord were immunoreactive in the stage 15 embryo. In the dorsal root ganglion, trigeminal and vestibulocochlear ganglia, and para-esophageal and paratracheal ganglia, immunoreactive cells were observed first in the stage 15 embryo. In the stage 21 embryo, immunoreactivity was observed around the peripheral respiratory tract. As the appearance of .gamma.-enolase in neurons is related to functional and morphological maturation, our study will provide descriptive information for the evaluation of neuronal development in early human embryos.