Age-related decrease in sympathetic sprouting is primarily due to decreased target receptivity: implications for understanding brain aging.

摘要: Abstract Aging of the nervous system is characterized by reduced anatomical plasticity. The cause this decreased plasticity not known because it usually possible to distinguish between extrinsic and intrisic factors that affect neuronal growth. One example age-related amenable such analysis growth sympathetic axons into rat hippocampal formation following septal denervation. This sprouting response can be elicited throughout lifespan but drastically in aged animals. reduction ingrowth could theoretically due receptivity target (reduced trophic support or increased inhibition growth), responsivity neurons a combination both factors. In order test relative contributions age tissue observed animals, superior cervical ganglia were transplanted from young animals old (y/o) (o/y) as well autologously within same (y/y o/o). extent survival assessed with fluorescence histochemical methods. was significantly greater hosts compared regardless donor. addition, younger than donor age. These results indicate aging primarily tissue.