Development of the principal sensory nucleus of the trigeminal nerve of the rat and evidence for a transient synaptic field in the trigeminal sensory tract.
The early development of the principal sensory nucleus of the trigeminal nerve (PSN) was examined to determine whether spatiotemporal patterns of synaptogenesis coincide with patterns in neuronal generation, migration, and death. The morphogenesis of PSN neurons during the period from G16 to P14 was studied with a Golgi method. Prenatally, PSN neurons had dendrites that extended into the sensory tract of the trigeminal nerve (s5), and from as early as G18, these dendrites were studded with spines. The dendrites in the s5 degenerated or regressed in the early postnatal period so that the s5 was free of dendrites by P14. The development of anti-synapsin I immunoreactivity was traced from G14 to P10. Immunoreactive puncta (synaptic boutons) appeared in the medial third of the s5 transiently between G18 and P5. On the other hand, puncta in the PSN did not appear until G20, at which time they were confined to the lateral margin of the PSN. By P0, puncta were distributed throughout the PSN. Cytochrome oxidase activity in the PSN was low and unpatterned prenatally. Postnatally, cytochrome oxidase activity intensified and a segmented pattern of barreloids appeared in the ventral PSN on the day of birth. By P5, the complete pattern of barreloids, spanning the full width of the ventral PSN, was evident. The development of cytochrome oxidase activity in the PSN followed the lateral-to-medial gradient of synaptogenesis revealed by the development of synapsin 1 immunoreactivity. This gradient is opposite of that for neuronal generation, migration, and death. Moreover, the s5 serves as a transient synaptic field.
al-Ghoul
W M
WM
Program in Physiology and Neurobiology, Rutgers University, Piscataway, New Jersey.
Miller
M W
MW
D000344:Afferent Pathways / Q000166:cytology / Q000254:growth & development; D000818:Animals; D002465:Cell Movement / Q000502:physiology; D003712:Dendrites / Q000502:physiology; D003576:Electron Transport Complex IV / Q000378:metabolism; D005260:Female; D006651:Histocytochemistry; D007150:Immunohistochemistry; D009410:Nerve Degeneration / Q000502:physiology; D009475:Neurons, Afferent / Q000502:physiology*; D011247:Pregnancy; D051381:Rats; D013569:Synapses / Q000201:enzymology / Q000502:physiology*; D016704:Synapsins / Q000276:immunology / Q000378:metabolism; D014278:Trigeminal Nuclei / Q000166:cytology / Q000201:enzymology / Q000254:growth & development*
D016704:Synapsins; D003576:Electron Transport Complex IV