Y Kameda

..These results indicate that the chicken glomus cells are able to produce NPY but that the level of its translation varies according to the location of the cells...

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..The neural progenitor markers, neurofilament 160 and TuJ1, are also absent from the parathyroid. Taken together, we suggest that Gcm2 supplies only some glial progenitor characteristics to the parathyroid rudiment...

..AgRP mRNA levels did not differ significantly between the null mutants and wild-type mice. Thus, up-regulation of the hypothalamic NPY system is probably a feature characteristic of Ngn3 null mice...

..5% of the value in wild-types at E17.5-E18.5. These results suggest that Hes1 plays a critical role in regulating the development of neural crest derivatives in the mouse cervical region...

..5, and HNK-1, which are continuous with the inferior vagal (nodose) ganglion, first surround and then invade both the carotid body rudiment and the other portions of the third branchial artery, becoming glomus cells...

..These changes in the tanycytes under different photoperiods may influence the portal circulation system and also the cell activity of the pars tuberalis, and may thus participate in photoperiodic regulation of the endocrine system...

..These results indicate that lack of the Hoxa3 gene affects the intrinsic ability of the third pharyngeal pouch to form the parathyroid rudiment and has no detectable effect on the migration of neural crest cells...

..Many cells immunoreactive for the S-100 protein, a sustentacular cell marker, appear in the mutant carotid body during fetal development. The Mash1 gene is thus required for the genesis of glomus cells but not for sustentacular cells...

..Thus, in the mutant mice, the ultimobranchial body fails to complete its differentiation program and finally dies. These results indicate that Mash1 enhances survival of the C-cell progenitors by inhibiting apoptosis...

..These results indicated that murine thyroid C cells are derived from the endodermal epithelial cells of the fourth pharyngeal pouch and do not originate from neural crest cells...

..We propose that the sympathetic ganglion provides glomus cell precursors into the third arch artery derivative in the presence of sensory fibers of the glossopharyngeal nerve...

..Thus, the separation, migration, and survival of the pharyngeal organs were impaired in the FRS2alpha(2F/2F) mutants...

..Defects in these genes result in malformations of the arch artery derivatives. This review should deepen our understanding of congenital human syndromes with abnormal patterns of pharyngeal arch arteries...

..Thus, the loss of Hes1 resulted in disturbances in the inductive and repulsive activities of the isthmic organizer. It is proposed that Hes1 plays a role in regulating the location and density of mesDA neurons...

..The superior cervical ganglion rather showed hypertrophic features in Hoxa3 homozygous mutants lacking the carotid body...

..Secretory granules were however larger in pinealectomized than in intact control chicks. These results suggest that the activity of PT-specific cells is mainly regulated by photoperiod...

..Thus, it seems that NPY neurons located in the mediobasal hypothalamus are involved in feeding behavior but not reproductive activity...

..Thus, the synthetic and secretory activities of the PT-specific cells were increased under extended darkness. The data indicate that the specific cells of the pars tuberalis are responsive to photoperiodic changes in the chick...

..Thus, the present study evidences that proenkephalin mRNA is synthesized in almost all C cells of chicken ultimobranchial glands throughout life. Enkephalin may be essential for C cell function...

..In 10-day-old chickens, TuJ1 immunoreactivity was restricted to the nerve fibers...

..Enkephalin-immunoreactive nerve fibers were characterized by the presence of granular vesicles, 60-160 nm in diameter, and frequently established direct contact with the surface of C cells.(ABSTRACT TRUNCATED AT 250 WORDS)..

..e., C cells differentiate along the neuronal lineage. During embryonic development, C cells of the chick ultimobranchial glands transiently express a number of neuronal properties...

..Chromogranin A- and neurotensin-immunoreactive cells began to appear at 16 days and 18 days of incubation, respectively. Galanin-, VIP-, and tyrosine hydroxylase-immunoreactive fibers were inconspicuous during embryonic life...

..These results indicate that the C cells cultured from early chick embryos (12- and 13-day-old) maintain the neuronal characteristics for long periods in vitro...

..In addition, C cells were partly covered with the long cytoplasmic processes of Schwann cells and were also in contact with the Schwann cell perikarya. The C cells in nerves appear to be controlled by neural stimulation...

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..Some cells were still elongated or irregular in shape and contained small secretory granules, 60-200 nm in diameter...

..Taken together, it is supposed that Hes1 signaling plays an essential role in regulating the development of various craniofacial structures derived from the cranial neural crest cells...

..All of these features suggest that C-cell activity, i.e., secretion of hormones and catecholamines, may be regulated by nerve stimuli...

..Thus, Hes1 is required for development of the pars tuberalis and its growth is dependent on the ventral diencephalon...

..The alpha-subunit synthesized by the PT-specific cells may therefore participate in the circadian and seasonal regulation of endocrine activities...

..In conclusion, nicotinamide stimulates long-term survival and neuronal differentiation of chick embryo C cells, and this culture system may provide a useful model for studying neuronal differentiation mechanisms...

..Thus, Hoxa3 is required for the growth and differentiation of the third pharyngeal arch. The defective development of the third pharyngeal arch may induce the anomalies of the carotid artery system...