THE VASOTOCIN SYSTEM IN THE QUAIL BRAIN:
CHANGES WITH AGE.
Soc. Neurosci.Abstracts, 22, 1890
C.Viglietti-Panzica*°, E.Garcia-Ojeda°, N.Aste°, G.C.Panzica°,
N.Thompson°°, M.A.Ottinger°°.
°Dept. Anatomy, Pharmacology & Forensic Med., Univ. Torino,
I- 10126 Torino, Italy, and °°Dept. Poultry Sc., UMD, College Park,
MD, USA.
Immunocytochemical techniques were used to investigate
morphological changes in vasotocin (VT) positive cells and fibers in hypothalamic
and extrahypothalamic regions of male Japanese quail of different age and
reproductive status. Four groups of male quail were studied: young, sexually
active (6-months; YA), middle-aged, sexually active (18 months; MA), middle-aged,
sexually inactive (18 months; MI), old, sexually inactive (senescent, 36
months; OI). The anatomical distribution of VT cell clusters at diencephalic
level was similar in all considered groups. Specific morphological parameter,
including cell size, dendritic size and staining, number of somatodendritic
spines, and VT innervation in the neuropil appeared to vary during aging.
In particular, magnocellular neurons showed an increase of one or more
of the above-mentioned parameters in aging. These results indicate that
some groups of magnocellular VT-positive neurons are activated in aging,
whereas others remain unaltered. Small VT-positive neurons were observed
in several locations,decrease with aging was, however, detected only in
the medial preoptic nucleus (POM) and in nucleus of the stria terminalis
(nST). VT neurons project to a large number of brain areas, among them
a strong reduction of the innervation as well as of the immunostaining
intensity was observed in nST, POM, lateral septum, dorsomedial posterior
thalamus, nucleus intercollicularis, central gray, and optic tectum. These
data give evidence for specific changes in the VT system, rather than a
generalized age-related decline during aging. Some magnocellular elements
are activated, whereas testosterone sensitive regions show a decrease in
immunoreactivity for both cell bodies and fibers.
Work supported by grants from CNR, MURST, EU (GCP), NRI
92-37023-7742 (MAO) and NATO.