A Preliminary Description of the Sleep‐Related Neural Systems in the Brain of the Blue Wildebeest, Connochaetes taurinus

Abstract

The current study provides a detailed qualitative description of the organization of the cholinergic, catecholaminergic, serotonergic, orexinergic, and GABAergic sleep‐related systems in the brain of the blue wildebeest (Connocheates taurinus), along with a quantitative analysis of the pontine cholinergic and noradrenergic neurons, and the hypothalamic orexinergic neurons. The aim of this study was to compare the nuclear organization of these systems to other mammalian species and specifically that reported for other Cetartiodactyla. In the brain of the blue wildebeest, from the basal forebrain to the pons, the nuclear organization of the cholinergic, catecholaminergic, serotonergic, and orexinergic systems, for the most part, showed a corresponding nuclear organization to that reported in other mammals and more specifically the Cetartiodactyla. Furthermore, the description and distribution of the GABAergic system, which was examined through immunostaining for the calcium binding proteins calbindin, calretinin, and parvalbumin, was also similar to that seen in other mammals. These findings indicate that sleep in the blue wildebeest is likely to show typically mammalian features in terms of the global brain activity of the generally recognized sleep states of mammals, but Cetartiodactyl‐specific features of the orexinergic system may act to lower overall daily total sleep time in relation to similar sized non‐Cetartiodactyl mammals. Anat Rec, 2019. © 2019 American Association for Anatomy Anat Rec, 303:1977–1997, 2020. © 2019 American Association for Anatomy

Immunohistochemical study of the brainstem cholinergic system in the alpaca (<em>Lama pacos</em>) and colocalization with CGRP

“…Since the description of pontomesencephalic cholinergic nuclei has been extensively described in other species included in the Cetartiodactyla order, [1][2][3][4][5]14 this study will report mainly the cholinergic profiles observed in the medulla oblongata of the alpaca. Figure 1 shows the distribution patterns of ChAT and CGRP in the alpaca brainstem.…”

“…The location of the cholinergic cell groups in the pons and mesencephalon is similar to that described previously in the giraffe 14 as well as in other members of Cetartiodactyla order. [1][2][3][4][5] In the lateral pontine tegmentum, ventral to the anterior aspect of the inferior colliculus, ChAT-immunoreactive cell bodies and fibres were detected in the parabigeminal nucleus (Figure 1B). This is homologous to the Ch8 cell group in the human brainstem.…”

“…As the main reference, the mapping of de Souza et al 6,7 was followed for nomenclature and the location of the cholinergic groups in the alpaca brainstem, but in addition the distribution of these cell groups in other mammalian species was also consulted. [1][2][3][4][5]8,14,17,21,[23][24][25][26][27][28]30,32,36,37,40,41 The computerized digital mapping system Accustage MDPlot v5.2 (MD3-Digitizer, Accustage, Minnesota Datametrics, USA) was used to study the distribution of the immunoreactive neurons. Photographs were obtained with a digital camera attached to a Nikon Eclipse 80i microscope and using the Adobe Photograph 6.0 Software only the contrast and brightness of the images were adjusted.…”

“…This order includes cetaceans (whales and dolphins) as well as artiodactyls (eventoed ungulates), such as the giraffe and the sheep. [1][2][3][4][5] The knowledge of the physiology of alpaca is important since it is part of an important sector of the economy of different countries in South America due to the excellent quality of its wool. 6,7 The importance of this animal for the production sector has led studies of this species to focus on more practical aspects for its maintenance and reproduction, such as ovulation cycles or hormonal mechanisms.…”

“…Other species included in Cetartiodactyla order also exhibit specific brain specializations in order to surviving within their respective environments. [1][2][3][4][5] In this regard, several studies have been carried out on the alpaca brain reporting the distribution of neuroactive substances in the diencephalon 9,10 and the brainstem. 6,7,11 In the latter region, the distribution of leucine-enkephalin, 6 calcitonin gene-related peptide (CGRP) 7 and the colocalization of CGRP with tyrosine hydroxylase (TH) have been described.…”