2024-03-28T23:56:09Zhttps://eprints.lib.hokudai.ac.jp/dspace-oai/requestoai:eprints.lib.hokudai.ac.jp:2115/439512022-11-17T02:08:08Zhdl_2115_20039hdl_2115_116The Afferent Projections to the Anterior Part of the Preoptic Nucleus in Japanese Toads, Bufo japonicusFujita, YoshiyukiUrano, Akihisaopen access487The afferent innervations of the anterior part of the preoptic nucleus (APON), which is a presumed center for triggering reproductive behavior in anuran amphibians, were studied by use of a retrograde horseradish peroxidase (HRP) method in Japanese toads, Bufo japonicus. HRP was introduced into the APON through a bipolar theta-style glass microcapillary. Evidence of transported enzymatic activity was observed in perikarya and neuropil of the limbic cortex, the posterior part of the preoptic nucleus including the magnocellular part, the thalamic area, and the subtectal and tegmental regions including the reticular formation. Neurons in these regions appear to send their axons to the APON mainly via the medial and the lateral forebrain bundles, since HRP activity was distributed in these fiber structures in a continuous pattern from the APON to the region mentioned above. Localization of some HRP-labeled perikarya and fibers coincides with that of immunoreactive perikarya and fibers containing either luteinizing hormone-releasing hormone, vasotocin or thyrotropin-releasing hormone which have been considered to project to the APON.Zoological Society of Japan1986-08engjournal articleVoRhttp://hdl.handle.net/2115/439510289-0003Zoological Science34677686https://eprints.lib.hokudai.ac.jp/dspace/bitstream/2115/43951/1/ZS3-4_677-686.pdfapplication/pdf1.74 MB1986-08