Objective To explore the development of nitrergic neurons in the tongue of human fetus. Methods Using histochemical method of NADPH\|diaphorase, the differentiation, migration and development of the nitrergic neurons in the tongue of human fetus were studied. Results At the fourth month of the gestation, the round cells of epithelial tissue in tongue differentiated into fusiform nitrergic nerve cells, which moved from the epithelial tissue to subepithelial and muscular tissue. The bodies of nitrergic neurons were small, the positive reaction of nitric oxide synthase(NOS) was weak. The development of the process of nitrergic neurons might be divided into two phases:The first phase, the growth and development phase, occured from the fourth to the seventh month, the somatic size enlarged gradually, the numbers increased, the positive reaction of NOS increased gradually and reached its peak at the seventh month. The morphology of neurons was characterized by the development from the fusiform form to the tadpole form and then a diversity of shape. The second phase, the maturation phase, denoted the eighth to tenth month, the bodies of nitrergic neurons were obviously enlarged, the staining intensity of NOS was increased. The nitrergic neurons were scattered in the subepithelial layer and muscular tissue and the typical ganglionic cells were observed. Conclusion Nitrergic neurons of tongue originate from its epithelial tissue at the time of early fetal development. By the differentiation, migration, multiplication, growth and maturation, mature nitrergic neurons are formed. [

The changes of calcitonin gene-related peptide (CGRP) immunoreactive (IR) nerves in the tongue of the control and the irradiated rats were studied by using the methods of immunocytochemistry and microspectrophotometer (SPM) measuring techniques. The results show that CGRP-IR nerves were found in all tissues of the tongue. When acute intestinal radiation sickness (AIRS), the changes of CGRPIR nerves appeared obviously and might be divided into two phases: the stimulating phase was the first 24 hours after irradiation. CGRP-IR nerves of the tongue have obviously swollen, become thickness, the enlargement of the varicosities and an increase of accumulative material in the nerve fiber terminals. The destructive phase was from 24 to 72 hrs after irradiation. The characteristics of the lesion appeared in 48 hrs after irradiation. CGRP-IR nerves of the tongue body have reduced, part of CGRP-IR nervous bundles broken. The pathological changes were particularly evident in 72 hrs after irradiation. CGRP-IR nerves of the tongue body have marked reduced, even disappeared. All of CGRP-IR nerves of the root of the tongue almost broken completly with the exception of the structure like the motor end plates of the striated muscles and the CGRP-IR nerves in taste glands. By using SPM measuring, there was significant reduction in 48 hrs or 72 hrs after irradiation compared with the control group (P

By using histochemical and immunocytochemical techiques, the distribu- tion, origin, and properties of ACh, NE, CGRP, and NPY in tongue of rats were studied. The results revealed that the cholinergic (ACh) nerves, VIP and NPY im- munoreactive (IR) positive neurons mainly located in the subepithelial layer of the mucosa and the muscle layer. The nerves formed perivascular plexus of the blood vessels, surrounding the glands, and distributed in the muscle layer. The adrenergic nerves surrounded the blood vessels and gaglion cells forming a basket-like structure. CGRP-IR nerves were observed in all layers of tongue. The circumvallate and fungiform papillaes were densely innervated by the CGRP-IR nerves, whereas the filiform papillaes contained only a few nerves. Abundant CGRP-IR nerves surrounded the glands, the blood vessels, and formed motor end plate structure at the region of contacting the striated muscle of to- ngue. After treatment with capsaicin, a marked reduction in the CGRP-IR ner- ves were found in the mucosa of the tip and body of the tongue, but no ob- vious changes were seen in the other parts of the CGRP-IR nerves as well as the other type of the nerves. No NE and CGRP-IR neurons were observed. The characteristics of distribution suggested that the ACh,VIP and NPY nerves might be related to the regulation of regional blood flow and the secretion of the glands while the CGRP-IR nerves, besides the above effects, might be related to the regulation of motion and sensation.