| Institution: | 1. School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193 Johannesburg, South Africa;2. KSU Mammals Research Chair, Department of Zoology, King Saud University, Riyadh 11451, Saudi Arabia;3. Saudi Wildlife Authority, Riyadh 11575, Saudi Arabia;4. Centre for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark;5. Queensland Brain Institute, University of Queensland, St. Lucia 4072, Australia;1. UMR 7179 – CNRS/MNHN, Adaptive Mechanisms: From Organisms to Communities, Department of Ecology and Management of Biodiversity, 55 rue Buffon, 75321 Paris Cedex 5, France;2. Centre de Primatologie de l''Université de Strasbourg, Fort Foch, 67207 Niederhausbergen, France;3. Laboratoire de Neurosciences Cognitives et Adaptatives, UMR 7364, Université de Strasbourg, France;1. Division Antropologia, Facultad de Ciencias Naturales y Museo, UNLP, CONICET, 122 y 60, La Plata, Argentina;2. Departamento de Biologia Animal, UNICAMP, Campinas, São Paulo, Brazil;3. Laboratório de Instrumentação Nuclear, Centro de Tecnologia, UFRJ, Ilha do Fundão, Rio de Janeiro, Brazil;1. Department of Physiology, Kinki University Faculty of Medicine, 377-2 Ohnohigashi, Osaka-sayama, 589-8511, Japan;2. Department of Precision Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan |
| Abstract: | The present study describes the organization of the nuclei of the cholinergic, catecholaminergic, serotonergic and orexinergic systems in the brains of two members of Euarchontoglires, Lepus capensis and Tupaia belangeri. The aim of the present study was to investigate the nuclear complement of these neural systems in comparison to previous studies on Euarchontoglires and generally with other mammalian species. Brains were coronally sectioned and immunohistochemically stained with antibodies against choline acetyltransferase, tyrosine hydroxylase, serotonin and orexin-A. The majority of nuclei revealed in the current study were similar between the species investigated and to mammals generally, but certain differences in the nuclear complement highlight potential phylogenetic interrelationships within the Euarchontoglires and across mammals. In the northern tree shrew the nucleus of the trapezoid body contained neurons immunoreactive to the choline acetyltransferase antibody with some of these neurons extending into the lamellae within the superior olivary nuclear complex (SON). The cholinergic nature of the neurons of this nucleus, and the extension of cholinergic neurons into the SON, has not been noted in any mammal studied to date. In addition, cholinergic neurons forming the medullary tegmental field were also present in the northern tree shrew. Regarding the catecholaminergic system, the cape hare presented with the rodent specific rostral dorsal midline medullary nucleus (C3), and the northern tree shrew lacked both the ventral and dorsal divisions of the anterior hypothalamic group (A15v and A15d). Both species were lacking the primate/megachiropteran specific compact portion of the locus coeruleus complex (A6c). The nuclei of the serotonergic and orexinergic systems of both species were similar to those seen across most Eutherian mammals. Our results lend support to the monophyly of the Glires, and more broadly suggest that the megachiropterans are more closely related to the primates than are any other members of Euarchontoglires studied to date. |
