Ann. Endocrinol. (1994), 55, 46.
SEXUAL DIMORPHISM OF PEPTIDERGIC SYSTEMS IN QUAIL SEPTAL
REGION.
C.Viglietti-Panzica, M.Covello, N.Aste, and G.C.Panzica.
A large population of luteinizing hormone-releasing hormone
(LHRH)-immunoreactive neurons was previously identified within the septal
region of the Japanese quail, suggesting a direct involvement of this area
in the control of important aspects of avian reproduction. The study of distribution
of neuropeptides, neurotransmitters and receptors in this region is hence
of extreme interest to point to the putative neural regulations that can
take place at this level. To this purpose we performed immunohistochemical
or histochemical studies to detail the distribution of several peptidergic
[vasotocin (VT), substance P, neuropeptide Y, corticotropin releasing factor,
vasoactive polipetide (VIP)] pathways within the quail septal region. Collected
results suggest that multiple peptidergic innervation may occur in those regions
where the presence of a wide amount of sex steroid receptors [lateral septum
(SL), nucleus striae terminalis (nST)] or LHRH elements (caudal septum) has
been previously shown. In particular, we have analysed two of these peptidergic
pathways (VIP and VT) by comparing their distribution in sexually active
males and females. The amount of the peptidergic innervation was evaluated
by means of an image analyser. The percentage of the sampling area covered
by immunoreactive structures was determined by employing the threshold method
after shading correction of the digitized image. The data revealed marked
and significant differences in the degree of innervation when comparing rostral
and caudal regions. Both systems displayed a sexual dimorphism in their distribution.
In particular, VIP innervation was more developed in the female at the level
of the pallial commissure, whereas it is more developed in the male at caudal
levels. For the VT system, the innervation is always more developed in the
male and it increases greatly in the caudal levels. It seems hence that the
peptidergic innervation of the quail septal region might represent another
sexually differentiated characteristic of the central nervous system. Experiments
are now in progress to test the idea that such a dimorphic pattern could
be influenced also by the hormonal status in the adult individual. This
study was supported by MURST (40 % and 60%) and CNR grants.
This thesis is available at the library of the Department
of Anatomy, Pharmacology, and Forensic medicine.
Copies of this thesis (italian and text only, in Word5.1 for Macintosh)
are available throught e-mail. Sent requests to
giancarlo.panzica@unito.it