Neurotrophin receptor and tyrosine hydroxylase gene expression in aged sympathetic neurons.
Neurobiol Aging
; 18(1): 67-79, 1997.
Article
in En
| MEDLINE
| ID: mdl-8983034
ABSTRACT
Ribonuclease protection measurements revealed decreases of 26% in p75 neurotrophin receptor mRNA and 30% in trkA mRNA in superior cervical ganglia (SCG) of aged Long-Evans rats. These declines were not related to the presence of a spatial memory impairment, whose presence is known to strongly predict increased hypothalamic-pituitary-adrenal axis activity in these aged animals. A similar decrease with age was observed in p75, but not cyclophilin mRNA levels in SCG from F-344 inbred rats. In situ hybridization with paired sections from mature and aged F-344 rats revealed a 25% decline in the mean neuronal labeling index (LI) for p75 mRNA. In other paired sections, mean trkA LI decreased 16%, tyrosine hydroxylase (TH) LI increased 74% and cyclophilin LI did not change. Neuronal hypertrophy, p75 decreases and TH increases all occurred to a greatest extent in intermediate-sized neurons, resembling those innervating the pineal and cerebral vessels. In contrast to other SCG targets, this innervation is known to decline nearly 50% with aging. Retrograde tracer/in situ hybridization studies will be required to establish whether decreased p75 represents a marker for selective axonal regression and also to determine the significance of increased TH and neuronal hypertrophy.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Sympathetic Nervous System
/
Tyrosine 3-Monooxygenase
/
Aging
/
Gene Expression Regulation, Enzymologic
/
Receptors, Nerve Growth Factor
/
Neurons
Type of study:
Prognostic_studies
Limits:
Animals
Language:
En
Journal:
Neurobiol Aging
Year:
1997
Document type:
Article
Affiliation country:
Canada