Immunoreactive vasotocin in the zebra finch brain (Taeniopygia guttata)

The distribution of vasotocin (VT)-immunoreactive cells and fibers in the zebra finch brain was studied with immunocytochemical techniques. A large number of VT-immunoreactive cells was found in the nucleus preopticus anterior and nucleus paraventricularis. In the lateral parts of the hypothalamus diffusely organized VT-immunoreactive cells were present. Some of these cells were found close to and embedded in the optic tract. An extra-hypothalamic parvocellular cell group was found at the level of the anterior commissure in the dorsal diencephalon. VT-immunoreactive fibers and varicosities were present in a number of extrahypothalamic regions i.e. the septum, the area ventralis of Tsai, the lateral habenula, the optic tectum, the substantia grisea centralis, the nucleus tractus solitarii, the lateral medulla, the nucleus intercollicularis and in the archistriatum surrounding the nucleus robustus archistriatalis. The VT-immunostaining in the lateral septum and dorsal diencephalon showed no sex differences and can not be influenced by testosterone administration.

the topography of the central VT-immunoreactive network is similar to that in another song bird i.e. the canary; but seasonal and testosterone-dependent changes in VT-immunostaining in the lateral septum and dorsal diencephalon are only observed in the canary.