Showing papers in "Zoological Science in 1987"

Extrahypothalamic Projection of Immunoreactive Vasotocin Fibers in the Brain of the Toad, Bufo japonicus

Abstract: Extrahypothalamic projection of vasotocin (A VT) fibers in the brain of the toad (Bufo japonicus) was examined immunohistochemically by the avidin-biotin-peroxidase complex (ABC) method. Immunoreactive A VT perikarya are localized in the nucleus preopticus pars magnocellularis. The A VT neurons send their immunoreactive varicose fibers to many discrete brain regions, such as the limbic cortex, the thalamus, the optic tectum and the lower brain stem, in addition to the neurohypophysis. A dense network of A VT fibers was found in the septal nuclei and the anterior part of the preoptic nucleus. A VT fibers which run postero-dorsad project to the nucleus posterocentralis thalami, the nucleus posterodorsalis tegmenti mesencephali, and the nucleus isthmi. Meanwhile, A VT fibers which run through in the dorsal infundibular region and then the mesencephalic reticular formation are distributed in the meduUa oblongata. These findings suggest that A VT acts as a neuromodulator or a local hormone in the toad brain.