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Schwalbe DC, Stornetta DS, Abraham-Fan RJ, Souza GMPR, Jalil M, Crook ME, Campbell JN, Abbott SBG. Molecular Organization of Autonomic, Respiratory, and Spinally-Projecting Neurons in the Mouse Ventrolateral Medulla. J Neurosci 2024; 44:e2211232024. [PMID: 38918066 PMCID: PMC11293450 DOI: 10.1523/jneurosci.2211-23.2024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 06/05/2024] [Accepted: 06/11/2024] [Indexed: 06/27/2024] Open
Abstract
The ventrolateral medulla (VLM) is a crucial region in the brain for visceral and somatic control, serving as a significant source of synaptic input to the spinal cord. Experimental studies have shown that gene expression in individual VLM neurons is predictive of their function. However, the molecular and cellular organization of the VLM has remained uncertain. This study aimed to create a comprehensive dataset of VLM cells using single-cell RNA sequencing in male and female mice. The dataset was enriched with targeted sequencing of spinally-projecting and adrenergic/noradrenergic VLM neurons. Based on differentially expressed genes, the resulting dataset of 114,805 VLM cells identifies 23 subtypes of neurons, excluding those in the inferior olive, and five subtypes of astrocytes. Spinally-projecting neurons were found to be abundant in seven subtypes of neurons, which were validated through in situ hybridization. These subtypes included adrenergic/noradrenergic neurons, serotonergic neurons, and neurons expressing gene markers associated with premotor neurons in the ventromedial medulla. Further analysis of adrenergic/noradrenergic neurons and serotonergic neurons identified nine and six subtypes, respectively, within each class of monoaminergic neurons. Marker genes that identify the neural network responsible for breathing were concentrated in two subtypes of neurons, delineated from each other by markers for excitatory and inhibitory neurons. These datasets are available for public download and for analysis with a user-friendly interface. Collectively, this study provides a fine-scale molecular identification of cells in the VLM, forming the foundation for a better understanding of the VLM's role in vital functions and motor control.
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Affiliation(s)
- Dana C Schwalbe
- Departments of Biology, University of Virginia, Charlottesville, Virginia 22904
| | | | | | | | - Maira Jalil
- Departments of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - Maisie E Crook
- Departments of Biology, University of Virginia, Charlottesville, Virginia 22904
| | - John N Campbell
- Departments of Biology, University of Virginia, Charlottesville, Virginia 22904
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Malungo IB, Mokale R, Bertelsen MF, Manger PR. Cholinergic, catecholaminergic, serotonergic, and orexinergic neuronal populations in the brain of the lesser hedgehog tenrec (Echinops telfairi). Anat Rec (Hoboken) 2023; 306:844-878. [PMID: 36179372 DOI: 10.1002/ar.25092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Revised: 09/26/2022] [Accepted: 09/26/2022] [Indexed: 11/07/2022]
Abstract
The current study provides an analysis of the cholinergic, catecholaminergic, serotonergic, and orexinergic neuronal populations, or nuclei, in the brain of the lesser hedgehog tenrec, as revealed with immunohistochemical techniques. For all four of these neuromodulatory systems, the nuclear organization was very similar to that observed in other Afrotherian species and is broadly similar to that observed in other mammals. The cholinergic system shows the most variation, with the lesser hedgehog tenrec exhibiting palely immunopositive cholinergic neurons in the ventral portion of the lateral septal nucleus, and the possible absence of cholinergic neurons in the parabigeminal nucleus and the medullary tegmental field. The nuclear complement of the catecholaminergic, serotonergic and orexinergic systems showed no specific variances in the lesser hedgehog tenrec when compared to other Afrotherians, or broadly with other mammals. A striking feature of the lesser hedgehog tenrec brain is a significant mesencephalic flexure that is observed in most members of the Tenrecoidea, as well as the closely related Chrysochlorinae (golden moles), but is not present in the greater otter shrew, a species of the Potomogalidae lineage currently incorporated into the Tenrecoidea. In addition, the cholinergic neurons of the ventral portion of the lateral septal nucleus are observed in the golden moles, but not in the greater otter shrew. This indicates that either complex parallel evolution of these features occurred in the Tenrecoidea and Chrysochlorinae lineages, or that the placement of the Potomogalidae within the Tenrecoidea needs to be re-examined.
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Affiliation(s)
- Illke B Malungo
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Reabetswe Mokale
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Mads F Bertelsen
- Centre for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
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Maseko BC, Patzke N, Fuxe K, Manger PR. Architectural Organization of the African Elephant Diencephalon and Brainstem. BRAIN, BEHAVIOR AND EVOLUTION 2013; 82:83-128. [DOI: 10.1159/000352004] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 05/03/2013] [Indexed: 11/19/2022]
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Calvey T, Patzke N, Kaswera C, Gilissen E, Bennett NC, Manger PR. Nuclear organisation of some immunohistochemically identifiable neural systems in three Afrotherian species—Potomogale velox, Amblysomus hottentotus and Petrodromus tetradactylus. J Chem Neuroanat 2013; 50-51:48-65. [DOI: 10.1016/j.jchemneu.2013.01.002] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2012] [Revised: 01/23/2013] [Accepted: 01/23/2013] [Indexed: 10/27/2022]
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Abbott SBG, DePuy SD, Nguyen T, Coates MB, Stornetta RL, Guyenet PG. Selective optogenetic activation of rostral ventrolateral medullary catecholaminergic neurons produces cardiorespiratory stimulation in conscious mice. J Neurosci 2013; 33:3164-77. [PMID: 23407970 PMCID: PMC3596815 DOI: 10.1523/jneurosci.1046-12.2013] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 12/18/2012] [Accepted: 01/02/2013] [Indexed: 02/07/2023] Open
Abstract
Activation of rostral ventrolateral medullary catecholaminergic (RVLM-CA) neurons e.g., by hypoxia is thought to increase sympathetic outflow thereby raising blood pressure (BP). Here we test whether these neurons also regulate breathing and cardiovascular variables other than BP. Selective expression of ChR2-mCherry by RVLM-CA neurons was achieved by injecting Cre-dependent vector AAV2-EF1α-DIO-ChR2-mCherry unilaterally into the brainstem of dopamine-β-hydroxylase(Cre/0) mice. Photostimulation of RVLM-CA neurons increased breathing in anesthetized and conscious mice. In conscious mice, photostimulation primarily increased breathing frequency and this effect was fully occluded by hypoxia (10% O(2)). In contrast, the effects of photostimulation were largely unaffected by hypercapnia (3 and 6% CO(2)). The associated cardiovascular effects were complex (slight bradycardia and hypotension) and, using selective autonomic blockers, could be explained by coactivation of the sympathetic and cardiovagal outflows. ChR2-positive RVLM-CA neurons expressed VGLUT2 and their projections were mapped. Their complex cardiorespiratory effects are presumably mediated by their extensive projections to supraspinal sites such as the ventrolateral medulla, the dorsal vagal complex, the dorsolateral pons, and selected hypothalamic nuclei (dorsomedial, lateral, and paraventricular nuclei). In sum, selective optogenetic activation of RVLM-CA neurons in conscious mice revealed two important novel functions of these neurons, namely breathing stimulation and cardiovagal outflow control, effects that are attenuated or absent under anesthesia and are presumably mediated by the numerous supraspinal projections of these neurons. The results also suggest that RVLM-CA neurons may underlie some of the acute respiratory response elicited by carotid body stimulation but contribute little to the central respiratory chemoreflex.
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Affiliation(s)
| | - Seth D. DePuy
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
| | - Thanh Nguyen
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
| | - Melissa B. Coates
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
| | - Ruth L. Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
| | - Patrice G. Guyenet
- Department of Pharmacology, University of Virginia, Charlottesville, VA 22908
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Kruger JL, Patzke N, Fuxe K, Bennett NC, Manger PR. Nuclear organization of cholinergic, putative catecholaminergic, serotonergic and orexinergic systems in the brain of the African pygmy mouse (Mus minutoides): organizational complexity is preserved in small brains. J Chem Neuroanat 2012; 44:45-56. [PMID: 22554581 DOI: 10.1016/j.jchemneu.2012.04.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2012] [Revised: 04/16/2012] [Accepted: 04/16/2012] [Indexed: 11/16/2022]
Abstract
This study investigated the nuclear organization of four immunohistochemically identifiable neural systems (cholinergic, catecholaminergic, serotonergic and orexinergic) within the brain of the African pygmy mouse (Mus minutoides). The African pygmy mice studied had a brain mass of around 275 mg, making these the smallest rodent brains to date in which these neural systems have been investigated. In contrast to the assumption that in this small brain there would be fewer subdivisions of these neural systems, we found that all nuclei generally observed for these systems in other rodent brains were also present in the brain of the African pygmy mouse. As with other rodents previously studied in the subfamily Murinae, we observed the presence of cortical cholinergic neurons and a compactly organized locus coeruleus. These two features of these systems have not been observed in the non-Murinae rodents studied to date. Thus, the African pygmy mouse displays what might be considered a typical Murinae brain organization, and despite its small size, the brain does not appear to be any less complexly organized than other rodent brains, even those that are over 100 times larger such as the Cape porcupine brain. The results are consistent with the notion that changes in brain size do not affect the evolution of nuclear organization of complex neural systems. Thus, species belonging to the same order generally have the same number and complement of the subdivisions, or nuclei, of specific neural systems despite differences in brain size, phenotype or time since evolutionary divergence.
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Affiliation(s)
- Jean-Leigh Kruger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown 2193, Johannesburg, South Africa
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Dell LA, Kruger JL, Bhagwandin A, Jillani NE, Pettigrew JD, Manger PR. Nuclear organization of cholinergic, putative catecholaminergic and serotonergic systems in the brains of two megachiropteran species. J Chem Neuroanat 2010; 40:177-95. [DOI: 10.1016/j.jchemneu.2010.05.008] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2010] [Revised: 05/28/2010] [Accepted: 05/28/2010] [Indexed: 10/19/2022]
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Pieters RP, Gravett N, Fuxe K, Manger PR. Nuclear organization of cholinergic, putative catecholaminergic and serotonergic nuclei in the brain of the eastern rock elephant shrew, Elephantulus myurus. J Chem Neuroanat 2010; 39:175-88. [PMID: 20067831 DOI: 10.1016/j.jchemneu.2010.01.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 12/23/2009] [Accepted: 01/01/2010] [Indexed: 11/29/2022]
Abstract
The organization of the nuclear subdivisions of the cholinergic, putative catecholaminergic and serotonergic systems of the brain of the elephant shrew (Elephantulus myurus) were determined following immunohistochemistry for choline acetyltransferase, tyrosine hydroxylase and serotonin, respectively. This was done in order to determine if differences in the nuclear organization of these systems in comparison to other mammals were evident and how any noted differences may relate to specialized behaviours of the elephant shrew. The elephant shrew belongs to the order Macroscelidea, and forms part of the Afrotherian mammalian cohort. In general, the organization of the nuclei of these systems resembled that described in other mammalian species. The cholinergic system showed many features in common with that seen in the rock hyrax, rodents and primates; however, specific differences include: (1) cholinergic neurons were observed in the superior and inferior colliculi, as well as the cochlear nuclei; (2) cholinergic neurons were not observed in the anterior nuclei of the dorsal thalamus as seen in the rock hyrax; and (3) cholinergic parvocellular nerve cells forming subdivisions of the laterodorsal and pedunculopontine tegmental nuclei were not observed at the midbrain/pons interface as seen in the rock hyrax. The organization of the putative catecholaminergic system was very similar to that seen in the rock hyrax and rodents except for the lack of the rodent specific C3 nucleus, the dorsal division of the anterior hypothalamic group (A15d) and the compact division of the locus coeruleus (A6c). The nuclear organization of the serotonergic system was identical to that seen in all eutherian mammals studied to date. The additional cholinergic neurons found in the cochlear nucleus and colliculi may relate to a specific acoustic signalling system observed in elephant shrews expressed when the animals are under stress or detect a predator. These neurons may then function to increase attention to this type of acoustic signal termed foot drumming.
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Affiliation(s)
- Raymond P Pieters
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, South Africa
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Chaillou E, Tillet Y, Malbert CH. Organisation of the catecholaminergic system in the vagal motor nuclei of pigs: A retrograde fluorogold tract tracing study combined with immunohistochemistry of catecholaminergic synthesizing enzymes. J Chem Neuroanat 2009; 38:257-65. [DOI: 10.1016/j.jchemneu.2009.07.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2009] [Revised: 07/07/2009] [Accepted: 07/08/2009] [Indexed: 10/20/2022]
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Bux F, Bhagwandin A, Fuxe K, Manger PR. Organization of cholinergic, putative catecholaminergic and serotonergic nuclei in the diencephalon, midbrain and pons of sub-adult male giraffes. J Chem Neuroanat 2009; 39:189-203. [PMID: 19808092 DOI: 10.1016/j.jchemneu.2009.09.006] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 09/28/2009] [Accepted: 09/28/2009] [Indexed: 11/26/2022]
Abstract
The current study describes the nuclear organization and neuronal morphology of the cholinergic, putative catecholaminergic and serotonergic systems within the diencephalon, midbrain and pons of the giraffe using immunohistochemistry for choline acetyltransferase, tyrosine hydroxylase and serotonin. The giraffe has a unique phenotype (the long neck), a large brain (over 500 g) and is a non-domesticated animal, while previous studies examining the brains of other Artiodactyls have all been undertaken on domesticated animals. The aim of the present study was to investigate possible differences in the nuclear organization and neuronal morphology of the above-mentioned systems compared to that seen in other Artiodactyls and mammals. The nuclear organization of all three systems within the giraffe brain was similar to that of other Artiodactyls. Some features of interest were noted for the giraffe and in comparison to other mammals studied. The cholinergic neuronal somata of the laterodorsal tegmental nucleus were slightly larger than those of the pedunculopontine tegmental nucleus, a feature not described in other mammals. The putative catecholaminergic system of the giraffe appeared to lack an A15 dorsal nucleus, which is commonly seen in other mammals but absent in the Artiodactyls, had a large and expanded substantia nigra pars reticulata (A9 ventral), a small diffuse portion of the locus coerueleus (A6d), an expansive subcoeruleus (A7sc and A7d), and lacked the A4 nucleus of the locus coeruleus complex. The nuclear organization of the serotonergic system of the giraffe was identical to that seen in all other eutherian mammals studied to date. These observations in the giraffe demonstrate that despite significant changes in life history, phenotype, brain size and time of divergence, species within the same order show the same nuclear organization of the systems investigated.
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Affiliation(s)
- Faiza Bux
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, Johannesburg, South Africa
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Gravett N, Bhagwandin A, Fuxe K, Manger PR. Nuclear organization and morphology of cholinergic, putative catecholaminergic and serotonergic neurons in the brain of the rock hyrax, Procavia capensis. J Chem Neuroanat 2009; 38:57-74. [DOI: 10.1016/j.jchemneu.2009.02.005] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Revised: 02/18/2009] [Accepted: 02/27/2009] [Indexed: 11/28/2022]
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Limacher A, Bhagwandin A, Fuxe K, Manger PR. Nuclear organization and morphology of cholinergic, putative catecholaminergic and serotonergic neurons in the brain of the Cape porcupine (Hystrix africaeaustralis): Increased brain size does not lead to increased organizational complexity. J Chem Neuroanat 2008; 36:33-52. [DOI: 10.1016/j.jchemneu.2008.03.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Revised: 03/28/2008] [Accepted: 03/28/2008] [Indexed: 10/22/2022]
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13
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Nuclear organization and morphology of cholinergic, putative catecholaminergic and serotonergic neurons in the brains of two species of African mole-rat. J Chem Neuroanat 2008; 35:371-87. [DOI: 10.1016/j.jchemneu.2008.02.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 02/29/2008] [Accepted: 02/29/2008] [Indexed: 12/11/2022]
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Dwarika S, Maseko BC, Ihunwo AO, Fuxe K, Manger PR. Distribution and morphology of putative catecholaminergic and serotonergic neurons in the brain of the greater canerat, Thryonomys swinderianus. J Chem Neuroanat 2008; 35:108-22. [PMID: 17884333 DOI: 10.1016/j.jchemneu.2007.08.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2007] [Revised: 08/09/2007] [Accepted: 08/09/2007] [Indexed: 11/20/2022]
Abstract
The distribution, morphology and nuclear subdivisions of the putative catecholaminergic and serotonergic systems within the brain of the greater canerat (sometimes spelt cane rat) were identified following immunohistochemistry for tyrosine hydroxylase and serotonin. The aim of the present study was to investigate possible differences in the complement of nuclear subdivisions of these systems when comparing those of the greater canerat with reports of these systems in other rodents. The greater canerat was chosen for investigation as it is a large rodent (around 2.7kg body mass) and has an average brain mass of 13.75g, more than five times larger than that of the laboratory rat. The greater canerats used in the present study were caught from the wild, which is again another contrast to the laboratory rat. While these differences, especially that of size, may lead to the prediction of significant differences in the nuclear complement of these systems, we found that all nuclei identified in both systems in the laboratory rat and other rodents in several earlier studies had direct homologs in the brain of the greater canerat. Moreover, there were no additional nuclei in the brain of the greater canerat that are not found in the laboratory rat or other rodents. It is noted that the locus coeruleus of the laboratory rat differs in appearance to that reported for several other rodent species. The greater canerat is phylogenetically distant from the laboratory rat, but still a member of the order Rodentia. Thus, changes in the nuclear organization of these systems appears to demonstrate a form of constraint related to the phylogenetic level of the order.
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Affiliation(s)
- Sarika Dwarika
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown 2193, Johannesburg, South Africa
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Badlangana NL, Bhagwandin A, Fuxe K, Manger PR. Distribution and morphology of putative catecholaminergic and serotonergic neurons in the medulla oblongata of a sub-adult giraffe, Giraffa camelopardalis. J Chem Neuroanat 2007; 34:69-79. [PMID: 17544256 DOI: 10.1016/j.jchemneu.2007.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Revised: 05/02/2007] [Accepted: 05/02/2007] [Indexed: 11/22/2022]
Abstract
The current study details the nuclear parcellation and appearance of putative catecholaminergic and serotonergic neurons within the medulla oblongata of a sub-adult giraffe, using immunohistochemistry for tyrosine hydroxylase and serotonin. We hypothesized that the unusual phenotype of the giraffe, this being the long neck and potential axonal lengthening of these neurons, may pose specific problems in terms of the efficient functioning of these systems, as several groups of catecholaminergic and serotonergic neurons, especially of the medulla, are known to project to the entire spinal cord. This specific challenge may lead to observable differences in the nuclear parcellation and morphology of these systems in the giraffe. Our personal observations in the giraffe reveal that, as with other Artiodactyls, the spinal cord extends to the caudal end of the sacral vertebrae. Within the giraffe medulla we found evidence for five putative catecholaminergic (neurons containing tyrosine hydroxylase) and five serotonergic nuclei. In terms of both morphological appearance of the neurons and nuclear parcellation we did not find any evidence for features that may be considered affected by the phenotype of the giraffe. The nuclear parcellation and appearance of both the putative catecholaminergic and serotonergic systems in the medulla of the giraffe studied are strikingly similar to that seen in previous studies of other Artiodactyls. We interpret these findings in terms of a growing literature detailing order specific phylogenetic constraints in the evolution of these neuromodulatory systems.
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Affiliation(s)
- N Ludo Badlangana
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown 2193, Johannesburg, Republic of South Africa
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Maseko BC, Bourne JA, Manger PR. Distribution and morphology of cholinergic, putative catecholaminergic and serotonergic neurons in the brain of the Egyptian rousette flying fox, Rousettus aegyptiacus. J Chem Neuroanat 2007; 34:108-27. [PMID: 17624722 DOI: 10.1016/j.jchemneu.2007.05.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2007] [Revised: 05/23/2007] [Accepted: 05/23/2007] [Indexed: 10/23/2022]
Abstract
Over the past decade much controversy has surrounded the hypothesis that the megachiroptera, or megabats, share unique neural characteristics with the primates. These observations, which include similarities in visual pathways, have suggested that the megabats are more closely related to the primates than to the other group of the Chiropteran order, the microbats, and suggests a diphyletic origin of the Chiroptera. To contribute data relevant to this debate, we used immunohistochemical techniques to reveal the architecture of the neuromodulatory systems of the Egyptian rousette (Rousettus aegypticus), an echolocating megabat. Our findings revealed many similarities in the nuclear parcellation of the cholinergic, putative catecholaminergic and serotonergic systems with that seen in other mammals including the microbat. However, there were 11 discrete nuclei forming part of these systems in the brain of the megabat studied that were not evident in an earlier study of a microbat. The occurrence of these nuclei align the megabat studied more closely with primates than any other mammalian group and clearly distinguishes them from the microbat, which aligns with the insectivores. The neural systems investigated are not related to such Chiropteran specializations as echolocation, flight, vision or olfaction. If neural characteristics are considered strong indicators of phylogenetic relationships, then the data of the current study strongly supports the diphyletic origin of Chiroptera and aligns the megabat most closely with primates in agreement with studies of other neural characters.
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Affiliation(s)
- Busisiwe C Maseko
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown 2193, Johannesburg, South Africa
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Moon DJ, Maseko BC, Ihunwo AO, Fuxe K, Manger PR. Distribution and morphology of catecholaminergic and serotonergic neurons in the brain of the highveld gerbil, Tatera brantsii. J Chem Neuroanat 2007; 34:134-44. [PMID: 17606363 DOI: 10.1016/j.jchemneu.2007.06.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Revised: 05/29/2007] [Accepted: 06/03/2007] [Indexed: 11/17/2022]
Abstract
The distribution, morphology and nuclear subdivisions of the putative catecholaminergic and serotonergic systems within the brain of the highveld gerbil were identified following immunohistochemistry for tyrosine hydroxylase and serotonin. The aim of the present study was to investigate possible differences in the complement of nuclear subdivisions of these systems when comparing those of the highveld gerbil with those of the laboratory rat. The highveld gerbil was chosen as it is relatively closely related to the laboratory rat, but the Gerbillinae and Murinae lineages diverged over 20 million years ago. Moreover, even though brain sizes are similar, the life history and phenotypes between these two species are substantially different. The gerbils used in the present study were caught from the wild, which is again another contrast to the laboratory rat. While these differences may lead to the prediction of significant differences in the nuclear complement of these systems, we found that all nuclei identified in both systems in the laboratory rat in several earlier studies had direct homologs in the brain of the highveld gerbil. Moreover, there were no additional nuclei in the brain of the highveld gerbil that are not found in the laboratory rat. The only discernable difference between the two species was a greater density and number of catecholaminergic neurons in the olfactory bulb of the highveld gerbil. Thus, the evolution of nuclear parcellation in these systems appears to demonstrate a form of phylogenetic constraint related to the order Rodentia.
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Affiliation(s)
- Don-Joon Moon
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, 7 York Road, Parktown, 2193 Johannesburg, Republic of South Africa
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Ruggiero DA, Zhao N, Anwar M, Sica AL. Organization of the newborn piglets vagal motor complex: insights into integrated autonomic control mechanisms. Auton Neurosci 2005; 115:41-53. [PMID: 15507405 DOI: 10.1016/j.autneu.2004.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2004] [Revised: 08/17/2004] [Accepted: 08/17/2004] [Indexed: 10/26/2022]
Abstract
Pediatric disorders frequently exhibit dysregulation of sympatho-vagal activity, and impaired control of cardiovascular vagal networks. Factors influencing the maturation of vagal networks are of special interest because they normally protect the heart and circulation, facilitate digestion, and preserve visceral metabolism. At present, scant literature exists regarding the development of vagal innervation of the heart. This study in neonatal swine, Sus scrofa, mapped the normal anatomy of vagal motor cell groups, with special focus on the origins of cardiomotor neurons. Right cardiac nerve branches, or the right thoracic vagal trunk were resected, inserted into capillary glass vials filled with 2% FluoroGold (FG) tracer solutions, and sealed to prevent leakage (false positives). Dorsal and ventral vagal complexes were identified on cross-sectioned tissues incubated in a well-characterized specific FG antibody. Thoracic and abdominal vagal motoneurons were cytologically heterogeneous, and predominantly medium-sized, polygonal cell bodies. Discrete longitudinal cell columns were observed, as well as organized arrays of elongate spindle-shaped cells in formation. Long axes and dendrites appeared to orient toward incoming peripheral sensory and central afferents, and were juxtaposed to cerebral microvasculature. The piglets' dorsal vagal complex is: (i) thick and long, comparable to ruminants, in contrast to much shorter lengths in non-ruminants, and (ii) the chief source of vagal motoneurons, forming discrete, topographically organized parasympathetic cell groups with distinct dendritic arbors. The cardiac motor subnucleus is localized to a highly restricted areal subunit of nucleus ambiguus' external formation in the vicinity of the obex. On the other hand, dorsal cardiac vagal motoneurons were few in number and diffusely distributed. Dorsal vagal motoneurons of neonatal swine likely projected primarily to the enteric nervous system, exerting excitatory influence over gastrointestinal activity.
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Affiliation(s)
- D A Ruggiero
- Department of Psychiatry and Anatomy and Cell Biology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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Smeets WJ, González A. Catecholamine systems in the brain of vertebrates: new perspectives through a comparative approach. BRAIN RESEARCH. BRAIN RESEARCH REVIEWS 2000; 33:308-79. [PMID: 11011071 DOI: 10.1016/s0165-0173(00)00034-5] [Citation(s) in RCA: 300] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
A comparative analysis of catecholaminergic systems in the brain and spinal cord of vertebrates forces to reconsider several aspects of the organization of catecholamine systems. Evidence has been provided for the existence of extensive, putatively catecholaminergic cell groups in the spinal cord, the pretectum, the habenular region, and cortical and subcortical telencephalic areas. Moreover, putatively dopamine- and noradrenaline-accumulating cells have been demonstrated in the hypothalamic periventricular organ of almost every non-mammalian vertebrate studied. In contrast with the classical idea that the evolution of catecholamine systems is marked by an increase in complexity going from anamniotes to amniotes, it is now evident that the brains of anamniotes contain catecholaminergic cell groups, of which the counterparts in amniotes have lost the capacity to produce catecholamines. Moreover, a segmental approach in studying the organization of catecholaminergic systems is advocated. Such an approach has recently led to the conclusion that the chemoarchitecture and connections of the basal ganglia of anamniote and amniote tetrapods are largely comparable. This review has also brought together data about the distribution of receptors and catecholaminergic fibers as well as data about developmental aspects. From these data it has become clear that there is a good match between catecholaminergic fibers and receptors, but, at many places, volume transmission seems to play an important role. Finally, although the available data are still limited, striking differences are observed in the spatiotemporal sequence of appearance of catecholaminergic cell groups, in particular those in the retina and olfactory bulb.
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Affiliation(s)
- W J Smeets
- Graduate School of Neurosciences of Amsterdam, Research Institute of Neurosciences, Amsterdam, The Netherlands.
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Sica AL, Greenberg HE, Ruggiero DA, Scharf SM. Chronic-intermittent hypoxia: a model of sympathetic activation in the rat. RESPIRATION PHYSIOLOGY 2000; 121:173-84. [PMID: 10963773 DOI: 10.1016/s0034-5687(00)00126-2] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
This review focuses upon the development of a small animal model that incorporates exposure to chronic-intermittent hypoxia to produce systemic hypertension similar to that experienced by humans with the obstructive sleep apnea syndrome. It has been suggested that experimentally-induced hypertension, like human hypertension, is due to activation of the sympathetic nervous system. That hypothesis is supported by physiological studies carried out in humans with obstructive sleep apnea as well as in animals exposed to chronic-intermittent hypoxia. Furthermore, recent anatomical studies of exposed animals strongly suggested that activation was widespread and included cortical and brainstem components of the sympathetic system. Such findings, while illustrating the complexity of modeling human disease in animals, also demonstrate the heuristic value of chronic-intermittent hypoxia as an experimental approach.
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Affiliation(s)
- A L Sica
- Department of Medicine, Pulmonary and Critical Care Division (Room C-20), Long Island Jewish Medical Center, Long Island Campus of the Albert Einstein College of Medicine, New Hyde Park, NY 11040, USA.
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Pearson PL, Anderson LL, Jacobson CD. The prepubertal ontogeny of neuropeptide Y-like immunoreactivity in the male Meishan pig brain. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 1996; 91:41-69. [PMID: 8821478 DOI: 10.1016/0165-3806(95)00161-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Neuropeptide Y (NPY) is widely distributed in the mammalian brain and is involved in numerous functions including the control of feeding, growth and reproduction. Therefore, NPY may be an important peptide to study in agricultural species. This study describes the immunohistochemical localization of NPY throughout prepubertal development in the Meishan pig, a Chinese breed known for its superior reproductive characteristics. Brains of animals from gestational day (g) 30 through postnatal day (pn) 50 (duration of pregnancy averaged 114 days) were processed using a standard immunohistochemical technique utilizing a commercially available rabbit anti-porcine NPY antibody. Neuropeptide Y-like immunoreactivity (NPY-IR) in cell bodies and fibers is evident in many areas of the brain at g30, including the basal telencephalon, hypothalamus, mesencephalon, pons, and medulla. Throughout prenatal development, cell bodies containing NPY-IR generally increase in number and distribution in the brain. During postnatal development the number of cell bodies displaying NPY-IR decreases. The arcuate nucleus of the hypothalamus, shows a dramatic reduction in the number of immunoreactive cell bodies between pn1 (day of birth) and pn20, just before weaning. The distribution of NPY-IR in fibers becomes more widespread throughout gestational development, showing a pattern by g110 that was characteristic of postnatal ages. The intensity of NPY-IR in fibers also increases throughout gestation. Some additional increases in immunoreactivity occur postnatally, especially in the periventricular hypothalamus and the hippocampus. Other brain areas like the caudate nucleus and putamen show decreases in immunoreactivity postnatally. The distribution of NPY-IR in cell bodies and fibers is similar to that seen in other species, including the rat, and supports the hypothesis that NPY participates in controlling feeding, growth and reproduction in the pig.
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Affiliation(s)
- P L Pearson
- Department of Veterinary Anatomy, Iowa State University, Ames 50011, USA
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Ruggiero DA, Tong S, Anwar M, Gootman N, Gootman PM. Hypotension-induced expression of the c-fos gene in the medulla oblongata of piglets. Brain Res 1996; 706:199-209. [PMID: 8822357 DOI: 10.1016/0006-8993(95)01173-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Neural networks that mediate the reflex response to baroreceptor withdrawal were explored in Sus scrofa. Induction of c-fos was used as a monitor of synaptic activity in response to hypotension sustained by systemic administration of a peripheral vasodilator, sodium nitroprusside. Patterns of c-fos gene expression were compared between Saffan-anesthetized experimental animals and age-matched normotensive controls administered vehicle. Effects of other variables were controlled including 1 h preoperative accommodation to the novel environment, anesthesia, blood gases and pH. Identical post-stimulus survival periods were allowed for accumulation of transcript. The c-fos protein, Fos, was identified immunocytochemically with two rabbit antisera raised against amino acids 1-131 of Fos or residues 4-17 of synthetic human transcript. Fos was identified in catecholaminergic neurons labeled with an antiserum to tyrosine hydroxylase (TH). Fos was induced in the nucleus tractus solitarii (NTS) of hypotensive piglets. Neurons encoding Fos matched projection patterns of first order visceral afferents. Induction was prominent in the dorsolateral nucleus coinciding with the baroreceptor field. Indices of increased neuronal activity were evident in other baroreceptor terminal sites, e.g., medial subnucleus, the medial commissural field, the intermediate subnucleus and a ventral A2 noradrenergic area. In reticular formation c-fos protein was induced in circumscribed columns in the lateral tegmental field (LTF) extending from facial nucleus to calamus scriptorius. Catecholaminergic (TH-positive) neurons expressed Fos in the porcine C1 and A1 areas of ventrolateral medulla. Fos was also induced in a dorsal intermediate reticular zone of LTF. Minor or inconsistent differences between experimental and control were observed in nucleus raphe pallidus, rostral paramedian reticular formation, upper thoracic intermediolateral cell column, and stellate ganglia. In conclusion, baroreceptor withdrawal in young animals induced patterns of neuronal response along established cardiovascular reflex pathways.
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Affiliation(s)
- D A Ruggiero
- Department of Neurology and Neuroscience, Cornell University College of Medicine, New York, NY 10021, USA
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Ruggiero DA, Chau L, Anwar M, Mtui EP, Golanov EV. Effect of cervical vagotomy on catecholaminergic neurons in the cranial division of the parasympathetic nervous system. Brain Res 1993; 617:17-27. [PMID: 8374739 DOI: 10.1016/0006-8993(93)90607-o] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
This study provides evidence of catecholaminergic neurons in the cranial division of the parasympathetic nervous system. Presumptive catecholaminergic preganglionic neurons in the dorsal motor nucleus of the vagus (DMX) were revealed by a clearcut depletion of intracellular catecholamine-synthesizing enzyme immunoreactivity induced by unilateral cervical vagotomy and identified on tissues immunocytochemically processed for tyrosine hydroxylase (TH), dopamine beta-hydroxylase (D beta H) or phenylethanolamine N-methyltransferase (PNMT). This experimental design was essential because of the recent failure in two species to reproduce data previously obtained in double-label (combined immunocytochemical-retrograde transport) studies. Vagotomy data confirmed three spatially-segregated populations of catecholaminergic visceromotor neurons in the DMX. These cell bodies were morphologically identical to preganglionic neurons observed on alternate tissues stained for Nissl substance or immunostained for choline acetyltransferase (ChAT), the enzyme biosynthesizing acetylcholine. Neurons in the central and medial DMX demonstrated fall-off of TH-like immunoreactivity (LI) ipsilateral to the vagotomy at levels caudal to the obex. This cell group is assumed to be predominantly dopaminergic since relatively few neurons at this level of the DMX expressed D beta H-LI and none were immunostained for PNMT. A second population of immunoreactive neurons, concentrated in the rostral-lateral region of the DMX, was depleted of D beta H-LI on the ipsilateral side but did not express PNMT. These visceromotor neurons may, therefore, biosynthesize noradrenaline and belong to the rostral pole of the A2 area. A third population of presumptive adrenergic vagal dorsomotor neurons in the rostral-medial DMX was depleted of TH-, D beta H- and PNMT-LI at levels of the ipsilateral nucleus anterior to obex. Patterns of depletion of cytoplasmic enzyme-immunoreaction product were identical in all cases irrespective of the site of the transection or the postoperative survival period. Quantitative analysis demonstrated statistically significant loss of immunolabeled neurons in rostral and caudal subgroups of the DMX on the side ipsilateral to the vagotomy. It is concluded that catecholaminergic processes in the vagus nerve, as previously identified by the aldehyde-induced histofluorescence method, may partly arise from the lower brainstem.
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Affiliation(s)
- D A Ruggiero
- Department of Neurology and Neuroscience, Cornell University Medical College, New York, NY 10021
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Dormer KJ, Anwar M, Ashlock SR, Ruggiero DA. Organization of presumptive catecholamine-synthesizing neurons in the canine medulla oblongata. Brain Res 1993; 601:41-64. [PMID: 8094313 DOI: 10.1016/0006-8993(93)91694-n] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Immunocytochemical methods were used to identify cells and processes containing two major catecholamine (CA)-biosynthetic enzymes in areas of the canine medulla implicated in autonomic control. Antisera were employed against tyrosine hydroxylase (TH) and phenylethanolamine N-methyltransferase (PNMT). These enzymes respectively catalyze the conversions of tyrosine to L-DOPA and noradrenaline to adrenaline. Immunocytochemical studies laid the groundwork for subsequent investigations in conscious dog in which we characterized an area of cardiovascular control in the rostral ventrolateral medulla (RVLM). In the anatomical studies, previously unidentified neuronal somata and processes were demonstrated in the canine medulla. Presumptive adrenergic (CI) neurons in the canine RVLM were subjacent to the nucleus ambiguous (NA) and most numerous at a level where the compact and semicompact divisions of NA merged. In contrast to their distribution in rodents, C1 neurons were skewed caudally and did not extend rostrally to the caudal pole of the facial nucleus. C1 neurons were also relatively less concentrated in the RVLM. A large number of C1 neurons extended dorsally into the lateral tegmental field (LTF). Most C1 neurons in the LTF (like those in the A1 area) were aligned with catecholaminergic (TH- and PNMT-ir) processes traversing the intermediate reticular zone. Since the numbers and locations of TH- and PNMT-ir neurons in the C1 area of the RVLM and rostral LTF were virtually identical on adjacent sections, it can be implicitly inferred that the enzymes are co-localized to the same somata and that these neurons are capable of biosynthesizing adrenaline. The C1 and A5 areas were clearly separated by a transitional zone, sparsely populated by TH-ir somata (1-2 cells per section), where the facial nucleus and rostral pole of the NA pars compacta (NAc) occupied the same level. A5 neurons were more abundant and complexly organized than suggested by previous CA-histofluorescence data. In addition, a new parvicellular subgroup was identified and composed of neurons containing TH but not PNMT. In contrast to other species, the A1 cell group was not confined to the VLM. A large number of A1 neurons extended into the caudal LTF and were situated between the nucleus tractus solitarii-motor vagal complex (NTS-X) and caudal VLM (CVLM). In contrast to previous reports, presumptive adrenergic (TH- and PNMT-ir) cell groups were more densely represented in the C2-3 areas of the canine NTS and dorsomedial reticular formation.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- K J Dormer
- Department of Physiology and Biophysics, University of Oklahoma, College of Medicine, Oklahoma City 73190
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