title: Neuronotrophic factors for mammalian brain neurons: injury induction in neonatal, adult and aged rat brain.
abstract: Tissue from neonatal, adult and aged Sprague-Dawley rat brain contained low levels of survival promoting activity for embryonic neurons from various rat brain regions. This basal neuronotrophic activity was 2-fold higher in adult and 4-fold higher in aged rat brain, with respect to that in neonatal brain. Tissue extracts also contained 4-fold higher levels of neuronotoxic activity in adult and aged than in neonatal brain. Ablation of the occipital/entorhinal cortex caused a 3-fold increase in neuronotrophic activity in the tissue surrounding the wound in neonates and 4-fold in adult and aged brain, with respect to the basal levels. Maximal activities occurred at 3 days, 6 days and 15 days postlesion in neonatal, adult and aged tissue respectively, and subsequently returned to basal levels. Neuronotoxic activity was not induced following injury. The slower neuronotrophic response to injury in older animals may be one of the determinant factors of the slower recovery from brain damage observed in aging.
mesh_terms: D000367:Age Factors; D000818:Animals; D000831:Animals, Newborn; D001681:Biological Assay; D001923:Brain Chemistry; D001930:Brain Injuries / Q000378:metabolism*; D002478:Cells, Cultured; D003342:Corpus Striatum; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins / Q000032:analysis*; D009498:Neurotoxins / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D009498:Neurotoxins