Age-related changes of enkephalinergic innervation of human sympathetic neurons.
The age-related changes in the distribution of enkephalin-immunoreactive (ENK-IR) nerve fibers in relation to the principal neurons were studied in 23 human sympathetic ganglia from patients aged between 22 and 98 years. There were no age-related changes in the diameter of nerve cells and the packing density of the neurons did not change. There was an age-related decrease in the proportion of neurons innervated by enkephalin-containing fibers. In all age groups the neurons innervated by ENK-IR nerve fibers were larger than those neurons which were not surrounded by ENK-IR nerves. The pigment material in the enkephalin-innervated neurons was non-osmiophilic. The small neurons containing dark neuromelanin type of age pigment were not innervated by ENK-IR nerves. It is speculated that ENK-IR preganglionic nerves play a role in maintaining neuronal integrity of sympathetic neurons.
Järvi
R
R
Department of Biomedical Sciences, University of Tampere, Finland.
Helen
P
P
Pelto-Huikko
M
M
Rapoport
S I
SI
Hervonen
A
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D004745:Enkephalins / Q000032:analysis*; D005728:Ganglia, Sympathetic / Q000166:cytology; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009474:Neurons / Q000032:analysis*; D012016:Reference Values; D013564:Sympathetic Nervous System / Q000166:cytology*
D004745:Enkephalins