title: Reciprocal changes in the expression of neurotrophin mRNAs in target tissues and peripheral nerves of aged rats.
abstract: trk receptors are downregulated in both dorsal root ganglion (DRG) and spinal motoneurons of aged rats with behavioral sensorimotor deficits. Here we provide evidence, using reverse transcription-polymerase chain reaction (RT-PCR), of decreased levels of neurotrophin (nerve growth factor, NGF; brain-derived neurotrophic factor, BDNF; neurotrophin-3, NT-3; and neurotrophin-4, NT-4) mRNAs in target muscles. Moreover, the degree of neurotrophin mRNA decrease in target muscles seems to co-vary with the extent of sensorimotor disturbances. In contrast, the peripheral nerve of aged rats showed a reciprocal regulation of neurotrophins, with increased levels of NGF, BDNF, and NT-4 mRNAs. Taken together, evidence suggest an aging-related attenuation of neurotrophin signaling between target tissues, on one hand, and DRG and motoneurons, on the other, and, furthermore, that target-derived neurotrophins regulate the expression levels of trk mRNAs in both DRG and motoneurons.
authors.affiliation: Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Y
authors.initials: Y
authors.lastname: Ming
authors.forename: E
authors.initials: E
authors.lastname: Bergman
authors.forename: E
authors.initials: E
authors.lastname: Edström
authors.forename: B
authors.initials: B
authors.lastname: Ulfhake
mesh_terms: D000818:Animals; D005260:Female; D005727:Ganglia, Spinal / Q000378:metabolism*; D009046:Motor Neurons / Q000378:metabolism*; D009414:Nerve Growth Factors / Q000235:genetics / Q000378:metabolism*; D010525:Peripheral Nerves / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012584:Sciatic Nerve / Q000378:metabolism*; D013116:Spinal Cord / Q000378:metabolism
chemical_list: D009414:Nerve Growth Factors; D012333:RNA, Messenger