A. Tokunaga et al., IMMUNOHISTOCHEMICAL CHARACTERIZATION OF THE SUPRACHIASMATIC NUCLEUS AND THE INTERGENICULATE LEAFLET IN THE HEREDITARY BILATERALLY MICROPHTHALMIC RAT, Neuroscience research, 27(1), 1997, pp. 57-63
Immunohistochemical observation was performed in the suprachiasmatic n
ucleus (SCN) and the intergeniculate leaflet (IGL) of hereditary bilat
erally microphthalmic rats without the optic nerve on both sides. In t
he microphthalmic rats, volume of the SCN reduced to ca. 70% of the no
rmal and numbers of the vasoactive intestinal polypeptide (VIP)-like i
mmunoreactive (lir) neurons were significantly decreased. Although the
arginine vasopressin (aVP)- and the VIP-lir neurons distributed in th
e dorsomedial and the ventrolateral part of the SCN, respectively, as
reported in the normal one, somatostatin-lir neurons, localizing mainl
y in a border area between the dorsomedial and the ventrolateral regio
n of the normal SCN, were shifted to the ventral part of the SCN in th
e microphthalmic rats. The ventral part of the SCN was covered with ne
uropeptide Y (NPY)-lir fibers in both normal and mutant rats. The IGL
was hardly delineated cytologically in the lateral geniculate nucleus
(LGN) of the mutant rats. NPY-lir neurons were found in the dorsal par
t of the ventral LGN, in contrast to their even distribution in the no
rmal IGL. These findings suggest that the IGL-SCN tract remains in the
hereditary microphthalmic rats without the retinal projections. (C) 1
997 Elsevier Science Ireland Ltd.