H.A. Oelschläger1 and H. Jastrow2
1) Department of Anatomy, Johann Wolfgang Goethe-University,
Theodor Stern-Kai 7, D-60590 Frankfurt a.M.;
2) Department of Anatomy, J. Gutenberg-University, Becherweg
13, D-55128 Mainz.
Five big brown bats (3m, 2f) ranging from juvenile to adult animals
(cryotome and cryostat sections) were investigated with the methods of
immunocytochemistry (Sternberger 1974).
Within the Nervus terminalis (N.t.), variation of LHRH cell number
was moderate (range 5-129; average: 68); there were almost twice as many
spindle-shaped cells as irregular cells. In the brain, the degree of variation
was about the same as in the N.t. (range: 528-1.047; average: 713); however,
the spindle-shaped cells were 3.5 times as numerous as the irregular cells.
In the nervous system as a whole, there were only minor differences
between left and right (averages: 350 [left] and 332 [right]). There was
so significant difference between both sexes and no obvious numerical trend
during postnatal ontogenesis. On an average, the postnatal big brows bat
exhibits 780 LHRH-ir cells within the N.t. and forebrain, which is distinctly
more than in the mole rat (Jastrow et al., this volume) and much more than
in the mouse (Schwanzel-Fukuda et al. 1987) and the musk shrew (Dellovade
and Rissman 1994). It should be noted that, within the Nervus terminalis
of mammals, the LHRH-ir cells represent only one neuron population, which
shows marked regression in parallel to the establishment of the brain-pituitary-gonadal
axis during the late fetal period.
* supported by Deutsche Forschungsgemeinschaft (DFG) Oel-103/2-1
and
Dr. Senckenbergische Stiftung, Frankfurt am Main, FRG