The nervus terminalis in amphibians: anatomy, chemistry and relationship with the hypothalamic gonadotropin-releasing hormone system.
The nervus terminalis (TN), a component of the olfactory system, is found in most vertebrates. The TN of some fishes and mammals contains neurons immunoreactive (ir) to gonadotropin-releasing hormone (LHRH), and to several other neuropeptides and neurotransmitter systems, but there is little information on TN chemistry in other vertebrate taxa. Using immunocytochemical techniques, we found LHRH-ir neurons in amphibian TNs. In anurans, but not in a urodele, the TN was also found to contain Phe-Met-Arg-Phe-NH2 (FMRFamide) immunoreactivity. LHRH-ir neurons of the TN and those of the septal-hypothalamic system are morphologically homogeneous and form a distinct anatomical continuum in amphibians. Based upon topographical and cytological criteria, we hypothesize that LHRH-ir systems in vertebrates might derive embryonically from the TN.
Muske
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Zoology Department, Oregon State University, Corvallis.
Moore
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FL
D000818:Animals; D003391:Cranial Nerves / Q000033:anatomy & histology*; D019835:FMRFamide; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007031:Hypothalamus / Q000033:anatomy & histology*; D007124:Immunoenzyme Techniques; D009412:Nerve Fibers / Q000033:anatomy & histology; D009474:Neurons / Q000648:ultrastructure; D009479:Neuropeptides / Q000378:metabolism; D009832:Olfactory Nerve / Q000033:anatomy & histology*; D009833:Olfactory Pathways / Q000033:anatomy & histology; D011894:Rana pipiens / Q000033:anatomy & histology*; D011898:Ranidae / Q000033:anatomy & histology*; D012455:Salamandridae / Q000033:anatomy & histology*
D009479:Neuropeptides; D007987:Gonadotropin-Releasing Hormone; D019835:FMRFamide