Age-associated and cell-type specific changes in NGF requirement for neurite regeneration from trigeminal ganglion cells of the shrew (Suncus murinus).
Low density (20-50 cells/cm2), dissociated cultures of trigeminal ganglion (TRG) cells of the shrew, were made in a serum-free medium, and neurite growth was compared across ages of the animal and between NGF-free and NGF-rich conditions. TRG cells from newborn shrew (0-3 days old), which grew long neurites in an NGF-rich medium, failed to grow any neurites in an NGF-free medium. In contrast, TRG cells from aged shrew (16-19 months), which grew neurites without NGF, exhibited no further increment in neurite length when NGF (50-200 ng/ml) was added to the culture medium. TRG cells from adult shrew (4-5 months) were revealed to be a mixture of NGF-dependent and NGF-independent cells. The NGF-dependent cells (20% of the population) had large-sized somata of 24-32 microns diameter (L-type cells) and 2-7 long neurites enriched with arborizations. The remaining NGF-independent cells (80%) had small-sized somata (15-25 microns, S-type cells), and grew 1-3 neurites with a small number of arborizations. These findings suggest that the primary sensory neuron of the shrew has a cell-type specific critical period in the aging process with respect to the requirement of NGF for neurite promotion.
Fukuda
J
J
Department of Physiology, Faculty of Medicine, University of Tokyo.
Aosaki
T
T
Keino
K
K
Yamaguchi
T
T
D000375:Aging / Q000473:pathology / Q000502:physiology*; D000818:Animals; D000831:Animals, Newborn; D001369:Axons / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D001769:Blood; D002478:Cells, Cultured; D003470:Culture Media; D008297:Male; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009416:Nerve Regeneration / Q000187:drug effects* / Q000502:physiology; D009475:Neurons, Afferent / Q000187:drug effects* / Q000502:physiology / Q000648:ultrastructure; D012788:Shrews / Q000033:anatomy & histology / Q000254:growth & development*; D012668:Trigeminal Ganglion / Q000187:drug effects / Q000473:pathology*
D003470:Culture Media; D009414:Nerve Growth Factors