Distribution and morphology of putative catecholaminergic and serotonergic neurons in the brain of the greater canerat, Thryonomys swinderianus

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Paul.Manger@wits.ac.za 2 Highlights  The organisation of four neural systems is described in the brains of three Afrotherians not previously studied  These systems are organised in a similar manner to other mammals.  There are features that reflect both phylogenetic and functional signals in the evolution of these neural systems.  The golden mole appears to be a "hyper-cholinergic" mammal, possessing cholinergic neurons in novel regions of the brain. AbstractThe present study describes the organization of the cholinergic, catecholaminergic, serotonergic and orexinergic (hypocretinergic) neurons in the brains of the giant otter shrew, the Hottentot golden mole and the four-toed sengi, three members of the mammalian super orderAfrotheria. The aim of the present study was to investigate the possible differences in the nuclear complement of these neural systems in comparison to previous studies on other Afrotheria species and other mammalian species. Brains of the golden mole, sengi and giant otter shrew were coronally sectioned and immunohistochemically stained with antibodies against cholineacetyl-transferase, tyrosine hydroxylase, serotonin and orexin-A. The majority of nuclei revealed in the current study were similar between the species investigated, to other Afrotherian species investigated, and to other mammals, but certain differences in the nuclear complement highlighted phylogenetic interrelationships. The golden mole was seen to have cholinergic interneurons in the cerebral cortex, hippocampus, olfactory bulb and amygdala. The four-toed sengi had cholinergic neurons in both colliculi and in the cochlear nucleus, but lacked the catecholaminergic A15d group in the hypothalamus. In both the golden mole and the four-toed sengi, the locus coeruleus (A6d group) was made up of few neurons. The golden mole also exhibited an unusual foreshortening of the brain, such that a major kink in the brainstem was evident. The results of this study, framed in a phylogenetic context, appear to indicate that the golden mole and four-toed sengi share a more recent common ancestor that diverged from the tenrec lineage early in the phylogenetic history of the Afrotherians.

Section: Caudal Clustermentioning

confidence: 50%

“…Maseko et al, 2007;Moon et al, 2007;Dwarika et al, 2008). The RVL began as a lateroventral continuation of 5HT+ neurons from the lower portion of the RMg extending over the pyramidal tracts and consolidating as a distinct column lateral to the inferior olives.…”

Section: Caudal Clustermentioning

confidence: 99%

Nuclear organisation of some immunohistochemically identifiable neural systems in three Afrotherian species—Potomogale velox, Amblysomus hottentotus and Petrodromus tetradactylus

Calvey

Patzke

Kaswera

et al. 2013

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“…Manger, 2005;Maseko et al, 2007;Bhagwandin et al, 2008;Dwarika et al, 2008;Limacher et al, 2008, Gravett et al, 2009, Pieters et al, 2010Bux et al, 2010). In terms of the orexinergic system this appears to hold true for most mammals; however, the observations of variance in the number of potential orexinergic nuclei in rodents (Nixon and Smale, 2007) may indicate greater organizational variance within an order for this diffusely projecting system than other systems previously studied.…”

Section: Introductionmentioning

confidence: 87%

Distribution of orexinergic neurons and their terminal networks in the brains of two species of African mole rats

Bhagwandin

Fuxé

Bennett

et al. 2011

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The distribution of orexinergic cell bodies and terminal networks within the brains of two species of African mole rat (Cape-dune mole rat -Bathyergus suillus and highveld mole rat -Cryptomys hottentotus) were identified using immunohistochemistry for Orexin-A.The aim of the study was to investigate possible differences in the nuclear complement and terminal distribution of this system by comparing those of the mole rats to published studies of other rodents and mammals. The wild-caught mole rats used in this study live a subterranean lifestyle and are well known for their regressed visual system, which may lead to the prediction of differences in the distribution of the cell bodies and the terminal networks; however, we found that both species of mole rat displayed orexinergic nuclei limited to the hypothalamus in regions similar to those previously reported for other rodent and mammalian species. No immunoreactive neurons could be identified, in either species of mole rat within the anterior hypothalamic paraventricular nucleus, as has been reported for Murid rodents. The terminal networks, while remaining similar between the species, are more strongly expressed in the Cape-dune mole rat than in the highveld mole rat.

“…Within the left and right ventrolateral medullary tegmentum a distinct anteroposterior column of 5HT+ neurons of moderate density extending from the level of the facial nucleus to the spinomedullary junction were observed. These have previously been termed the rostral and caudal ventrolateral serotonergic columns (e.g., Moon et al, 2007;Dwarika et al, 2008;Calvey et al, 2013). The RVL began as a lateroventral continuation of 5HT+ neurons from the lower portion of the RMg extending over the pyramidal tracts and trapezoid body, and consolidating as a distinct column lateral to the inferior olivary nuclear complex.…”

Section: Caudal Clustermentioning

confidence: 99%

Nuclear organisation of some immunohistochemically identifiable neural systems in five species of insectivore —Crocidura cyanea, Crocidura olivieri, Sylvisorex ollula, Paraechinus aethiopicus and Atelerix frontalis

Calvey

Patzke

Bennett

et al. 2016

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Paul.Manger@wits.ac.za 1 Highlights• Several neural systems in the brains of insectivores are described.• All species show a similar global pattern of organization.• Certain variations indicate a phylogenetic relationships between shrews and microchiropterans.• This study support the diphyletic hypothesis of bat evolution. AbstractThe organization of the cholinergic, catecholaminergic, and serotonergic neurons in the brains of five species of insectivores and the orexinergic (hypocretinergic) system in four insectivore species is presented. We aimed to investigate the nuclear complement of these neural systems in comparison to those of other mammalian species. Brains of insectivores were coronally sectioned and immunohistochemically stained with antibodies against cholineacetyltransferase, tyrosine hydroxylase, serotonin and orexin-A. The majority of nuclei were similar among the species investigated and to mammals in general, but certain differences in the nuclear complement highlighted potential phylogenetic interrelationships.In the cholinergic system, the three shrew species lacked parabigeminal and EdingerWestphal nuclei. In addition, the appearance of the laterodorsal tegmental nucleus in all insectivores revealed a mediodorsal arch. All three of these features are the same as those present in microchiropterans. The catecholaminergic system of the three shrew species lacked the A4 and A15d nuclei, as well as having an incipient A9v nucleus, again features found in microchiropteran brains. The serotonergic and orexinergic systems of the insectivores are similar to those seen across most Eutherian mammals. The analysis of similarities and differences across mammalian species indicates a potential phylogenetic relationship between the Soricidae (shrews) and the microchiropterans.