La. Miranda et Jm. Affanni, Thyrotropin-releasing hormone immunoreactivity in the brain and the pituitary during Bufo arenarum development, INT J DEV N, 18(1), 2000, pp. 47-52
Citations number
36
Categorie Soggetti
Neurosciences & Behavoir
Journal title
INTERNATIONAL JOURNAL OF DEVELOPMENTAL NEUROSCIENCE
The ontogeny of the thyrotropin releasing hormone (TRH) neuronal system was
evaluated by immunocytochemistry in Bufo arenarum. The first appearance of
TRH immunoreactive fibers was at early premetamorphosis. These fibers were
found in small numbers and weakly stained in the median eminence and pars
nervosa. With the advance of larval development. TRH-like material stained
intensely and tended to aggregate in the median eminence, pars nervosa and
pars intermedia. At climax stages immunoreactive fibers and perikarya (weak
ly stained) were also identified in the preoptic area. In adult specimens T
RH perikarya and neuronal fibers were found in the preoptic and infundibula
r nuclei of the hypothalamus and in the amygdala, septum and diagonal hand
of Broca of the telencephalon. In addition, TRH neuronal fibers and endings
were found in the preoptic-hypophyseal tract, the external zone of the med
ian eminence, the pars nervosa and pars intermedia. Fibers were absent in t
he pars distalis. This study represents the first immunocytochemical demons
tration of TRH in Bufo species, and serves as a basis for clarification of
the neuroendocrine regulation of metamorphosis. (C) 2000 ISDN. Published by
Elsevier Science Ltd. All rights reserved.