1
|
Freire MAM, Franca JG, Picanco-Diniz CW, Manger PR, Kaas JH, Pereira A. Organization of Somatosensory Cortex in the South American Rodent Paca (Cuniculus paca). BRAIN, BEHAVIOR AND EVOLUTION 2024; 98:275-289. [PMID: 38198769 DOI: 10.1159/000534469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 10/02/2023] [Indexed: 01/12/2024]
Abstract
INTRODUCTION The study of non-laboratory species has been part of a broader effort to establish the basic organization of the mammalian neocortex, as these species may provide unique insights relevant to cortical organization, function, and evolution. METHODS In the present study, the organization of three somatosensory cortical areas of the medium-sized (5-11 kg body mass) Amazonian rodent, the paca (Cuniculus paca), was determined using a combination of electrophysiological microelectrode mapping and histochemical techniques (cytochrome oxidase and NADPH diaphorase) in tangential sections. RESULTS Electrophysiological mapping revealed a somatotopically organized primary somatosensory cortical area (S1) located in the rostral parietal cortex with a characteristic foot-medial/head-lateral contralateral body surface representation similar to that found in other species. S1 was bordered laterally by two regions housing neurons responsive to tactile stimuli, presumably the secondary somatosensory (S2) and parietal ventral (PV) cortical areas that evinced a mirror-reversal representation (relative to S1) of the contralateral body surface. The limits of the putative primary visual (V1) and primary auditory (A1) cortical areas, as well as the complete representation of the contralateral body surface in S1, were determined indirectly by the histochemical stains. Like the barrel field described in small rodents, we identified a modular arrangement located in the face representation of S1. CONCLUSIONS The relative location, somatotopic organization, and pattern of neuropil histochemical reactivity in the three paca somatosensory cortical areas investigated are similar to those described in other mammalian species, providing additional evidence of a common plan of organization for the somatosensory cortex in the rostral parietal cortex of mammals.
Collapse
Affiliation(s)
| | - João G Franca
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | | | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, USA
| | - Antonio Pereira
- Institute of Technology, Federal University of Pará, Belem, Brazil
| |
Collapse
|
2
|
Astrocytosis, Inflammation, Axonal Damage and Myelin Impairment in the Internal Capsule following Striatal Ischemic Injury. Cells 2023; 12:cells12030457. [PMID: 36766798 PMCID: PMC9913724 DOI: 10.3390/cells12030457] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 12/29/2022] [Accepted: 01/20/2023] [Indexed: 02/04/2023] Open
Abstract
Secondary degeneration is defined as a set of destructive events that damage cells and structures that were initially spared or only peripherally affected by the primary insult, constituting a key factor for functional impairment after traumatic brain injury or stroke. In the present study, we evaluated the patterns of astrocytosis, inflammatory response, axonal damage and oligodendrocytes/myelin impairment in the internal capsule following a focal injection of endothelin-1 (ET-1) into the dorsal striatum. Animals were perfused at 1, 3 and 7 post-lesion days (PLD), and tissue was processed to immunohistochemistry for neutrophils (MBS1), macrophages/microglia (ED1), astrocytes (GFAP), axonal lesion (βAPP), oligodendrocytes (Tau) and myelin (MBP). A significant number of neutrophils was observed at 1PLD, followed by intense recruitment/activation of macrophages/microglia at 3PLD and astrocytic reaction with a peak at 7PLD. Oligodendrocyte damage was pronounced at 3PLD, remaining at 7PLD. Progressive myelin impairment was observed, with reduction of immunoreactivity at 7PLD. Axonal lesion was also identified, mainly at 7PLD. Our results indicate that acute inflammatory response elicited by the ischemic insult in the striatum can be associated with the axonal impairment and damage of both oligodendrocytes and myelin sheath identified in the internal capsule, which may be related to loss of tissue functionality observed in secondary degeneration.
Collapse
|
3
|
Microelectrode implants, inflammatory response and long-lasting effects on NADPH diaphorase neurons in the rat frontal cortex. Exp Brain Res 2022; 240:2569-2580. [PMID: 35947168 DOI: 10.1007/s00221-022-06434-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 08/03/2022] [Indexed: 11/04/2022]
Abstract
At present, one of the main therapeutic challenges comprises the development of technologies to improve the life quality of people suffering from different types of body paralysis, through the reestablishment of sensory and motor functions. In this regard, brain-machine interfaces (BMI) offer hope to effectively mitigate body paralysis through the control of paralyzed body parts by brain activity. Invasive BMI use chronic multielectrode implants to record neural activity directly from the brain tissue. While such invasive devices provide the highest amount of usable neural activity for BMI control, they also involve direct damage to the nervous tissue. In the cerebral cortex, high levels of the enzyme NADPH diaphorase (NADPH-d) characterize a particular class of interneurons that regulates neuronal excitability and blood supply. To gain insight into the biocompatibility of invasive BMI, we assessed the impact of chronic implanted tungsten multielectrode bundles on the distribution and morphology of NADPH-d-reactive neurons in the rat frontal cortex. NADPH-d neuronal labeling was correlated with glial response markers and with indices of healthy neuronal activity measured by electrophysiological recordings performed up to 3 months after multielectrode implantation. Chronic electrode arrays caused a small and quite localized structural disturbance on the implanted site, with neuronal loss and glial activation circumscribed to the site of implant. Electrodes remained viable during the entire period of implantation. Moreover, neither the distribution nor the morphology of NADPH-d neurons was altered. Overall, our findings provide additional evidence that tungsten multielectrodes can be employed as a viable element for long-lasting therapeutic BMI applications.
Collapse
|
4
|
Rocha GS, Freire MAM, Paiva KM, Oliveira RF, Norrara B, Morais PLAG, Oliveira LC, Engelberth RCGJ, Cavalcante JS, Cavalcanti JRLP. Effect of senescence on the tyrosine hydroxylase and S100B immunoreactivity in the nigrostriatal pathway of the rat. J Chem Neuroanat 2022; 124:102136. [PMID: 35809809 DOI: 10.1016/j.jchemneu.2022.102136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 07/04/2022] [Accepted: 07/05/2022] [Indexed: 10/17/2022]
Abstract
Senescence is a natural and progressive physiological event that leads to a series of morphophysiological alterations in the organism. The brain is the most vulnerable organ to both structural and functional changes during this process. Dopamine is a key neurotransmitter for the proper functioning of the brain, directly involved in circuitries related with emotions, learning, motivation and reward. One of the main dopamine- producing nuclei is the substantia nigra pars compacta (SNpc), which establish connections with the striatum forming the so-called nigrostriatal pathway. S100B is a calcium binding protein mainly expressed by astrocytes, involved in both intracellular and extracellular processes, and whose expression is increased following injury in the nervous tissue, being a useful marker in altered status of central nervous system. The present study aimed to analyze the impact of senescence on the cells immunoreactive for tyrosine hydroxylase (TH) and S100B along the nigrostriatal pathway of the rat. Our results show an decreased expression of S100B+ cells in SNpc. In addition, there was a significant decrease in TH immunoreactivity in both projection fibers and TH+ cell bodies. In the striatum, a decrease in TH immunoreactivity was also observed, as well as an enlargement of the white matter bundles. Our findings point out that senescence is related to the anatomical and neurochemical changes observed throughout the nigrostriatal pathway.
Collapse
Affiliation(s)
- Gabriel S Rocha
- Graduate Program in Biochemistry and Molecular Biology, University of the State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil
| | - Marco Aurelio M Freire
- Graduate Program in Health and Society, University of the State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil
| | - Karina M Paiva
- Graduate Program in Biochemistry and Molecular Biology, University of the State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil
| | - Rodrigo F Oliveira
- Graduate Program in Biochemistry and Molecular Biology, University of the State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil
| | - Bianca Norrara
- Laboratory of Experimental Neurology, University of the State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil
| | - Paulo Leonardo A G Morais
- Laboratory of Experimental Neurology, University of the State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil
| | - Lucidio C Oliveira
- Laboratory of Experimental Neurology, University of the State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil
| | | | | | - José Rodolfo L P Cavalcanti
- Graduate Program in Biochemistry and Molecular Biology, University of the State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil; Graduate Program in Health and Society, University of the State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil; Laboratory of Experimental Neurology, University of the State of Rio Grande do Norte (UERN), Mossoró, RN, Brazil.
| |
Collapse
|
5
|
Souza MF, Medeiros KAAL, Lins LCRF, Bispo JMM, Gois AM, Santos ER, Almeida-Souza TH, Melo JEC, Franco HS, Silva RS, Pereira-Filho EA, Freire MAM, Santos JR. Motor, memory, and anxiety-like behavioral impairments associated with brain-derived neurotrophic factor and dopaminergic imbalance after inhalational exposure to deltamethrin. Brain Res Bull 2022; 181:55-64. [PMID: 35041849 DOI: 10.1016/j.brainresbull.2022.01.004] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 01/12/2022] [Accepted: 01/13/2022] [Indexed: 12/16/2022]
Abstract
Believed to cause damage to the nervous system and possibly being associated with neurodegenerative diseases, deltamethrin (DM) is a type II pyrethroid used in pest control, public health, home environment, and vector control. The objective of this study was to evaluate the motor, cognitive and emotional changes associated with dopaminergic and BDNF imbalance after DM exposure in rats. Sixty Wistar rats (9-10 months-old) were used, under Ethics Committee on Animal Research license (ID 19/2017). The animals were randomly divided into four groups: control (CTL, 0.9% saline), DM2 (2mg DM in 1.6mL 0.9% saline), DM4 (4mg of DM in 1.6mL of 0.9% saline), and DM8 (8mg of DM in 1.6mL of 0.9% saline). DM groups were submitted to 9 or 15 inhalations, one every 48hours. Half of the animals from each group were randomly selected and perfused 24hours after the 9th or 15th inhalation. Throughout the experiment, the animal's behavior were evaluated using catalepsy test, open field, hole-board test, Modified Elevated Plus Maze, and social interaction. At the end of the experiments, the rats were perfused transcardially and their brains were processed for Tyrosine Hydroxylase (TH) and Brain derived neurotrophic factor (BDNF) immunohistochemistries. The animals submitted to 9 inhalations of DM showed a reduction in immunoreactivity for TH in the Substantia nigra pars compacta (SNpc), ventral tegmental area (VTA), and dorsal striatum (DS) areas, and an increase in BDNF in the DS and CA1, CA3 and dentate gyrus (DG) hippocampal areas. Conversely, the animals submitted to 15 inhalations of DM showed immunoreactivity reduced for TH in the SNpc and VTA, and an increase in BDNF in the hippocampal areas (CA3 and DG). Our results indicate that the DM inhalation at different periods induce motor and cognitive impairments in rats. Such alterations were accompanied by dopaminergic system damage and a possible dysfunction on synaptic plasticity.
Collapse
Affiliation(s)
- Marina F Souza
- Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Katty A A L Medeiros
- Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Lívia C R F Lins
- Laboratory of Behavioral and Evolutionary Neurobiology, Department of Biosciences, Federal University of Sergipe, Itabaiana, SE, Brazil
| | - José M M Bispo
- Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Auderlan M Gois
- Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Edson R Santos
- Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Thiago H Almeida-Souza
- Laboratory of Behavioral and Evolutionary Neurobiology, Department of Biosciences, Federal University of Sergipe, Itabaiana, SE, Brazil
| | - João E C Melo
- Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Heitor S Franco
- Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Rodolfo S Silva
- Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil
| | - Eduardo A Pereira-Filho
- Laboratory of Behavioral and Evolutionary Neurobiology, Department of Biosciences, Federal University of Sergipe, Itabaiana, SE, Brazil
| | - Marco Aurelio M Freire
- Graduate Program in Health and Society, University of the State of Rio Grande do Norte, Mossoró/RN, Brazil
| | - José R Santos
- Department of Physiology, Federal University of Sergipe, São Cristóvão, SE, Brazil.
| |
Collapse
|
6
|
Arrais AC, Melo LHMF, Norrara B, Almeida MAB, Freire KF, Melo AMMF, Oliveira LCD, Lima FOV, Engelberth RCGJ, Cavalcante JDS, Araújo DPD, Guzen FP, Freire MAM, Cavalcanti JRLP. S100B protein: general characteristics and pathophysiological implications in the Central Nervous System. Int J Neurosci 2020; 132:313-321. [DOI: 10.1080/00207454.2020.1807979] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Ana Cristina Arrais
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| | - Lívia Helena M. F. Melo
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| | - Bianca Norrara
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| | - Marina Abuquerque B. Almeida
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| | - Kalina Fernandes Freire
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| | - Acydalia Madruga M. F. Melo
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| | - Lucidio Clebeson de Oliveira
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| | - Francisca Overlânia Vieira Lima
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| | - Rovena Clara G. J. Engelberth
- Laboratory of Neurochemical Studies, Department of Physiology, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Jeferson de Souza Cavalcante
- Laboratory of Neurochemical Studies, Department of Physiology, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Dayane Pessoa de Araújo
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| | - Fausto Pierdoná Guzen
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| | - Marco Aurelio M. Freire
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| | - José Rodolfo L. P. Cavalcanti
- Laboratory of Experimental Neurology, Department of Biomedical Sciences, Faculty of Health Sciences, University of the State of Rio Grande do Norte, Mossoró, RN, Brazil
| |
Collapse
|
7
|
Santiago LF, Freire MAM, Picanço-Diniz CW, Franca JG, Pereira A. The Organization and Connections of Second Somatosensory Cortex in the Agouti. Front Neuroanat 2019; 12:118. [PMID: 30692919 PMCID: PMC6339897 DOI: 10.3389/fnana.2018.00118] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Accepted: 12/27/2018] [Indexed: 11/13/2022] Open
Abstract
In order to understand how the mammalian sensory cortex has been structured during evolution, it is necessary to compare data from different species across distinct mammalian lineages. Here, we investigated the organization of the secondary somatosensory area (S2) in the agouti (Dasyprocta aguti), a medium-sized Amazonian rodent, using microelectrode mapping techniques and neurotracer injections. The topographic map obtained from multiunit electrophysiological recordings were correlated with both cytochrome oxidase (CO) histochemistry and with patterns of corticocortical connections in tangential sections. The electrophysiological mapping of the lateral strip of parietal cortex adjacent to the primary somatosensory area (S1) revealed that S2 displays a mirror-reversed topographical representation of S1, but with a smaller cortical magnification factor. The caudal border of S2 is surrounded by sensory fields which also respond to auditory stimulation. BDA injections into the forelimb representation of S2 revealed a dense homotopic ipsilateral projection to S1, supplemented by a less dense projection to the caudolateral cortex located near the rhinal sulcus (parietal rhinal area) and to a frontal region probably associated with the motor cortex. Our findings were similar to those described in other mammalian species, reinforcing the existence of a common plan of organization for S2 in the mammalian parietal cortex.
Collapse
Affiliation(s)
- Lucidia F Santiago
- Laboratory of Investigations in Neurodegeneration and Infection, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Marco Aurelio M Freire
- Laboratory of Experimental Neuroprotection and Neuroregeneration, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - Cristovam W Picanço-Diniz
- Laboratory of Investigations in Neurodegeneration and Infection, Institute of Biological Sciences, Federal University of Pará, Belém, Brazil
| | - João G Franca
- Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| | - Antonio Pereira
- Institute of Technology, Federal University of Pará, Belém, Brazil
| |
Collapse
|
8
|
Pereira CM, Freire MAM, Santos JR, Guimarães JS, Dias-Florencio G, Santos S, Pereira A, Ribeiro S. Non-visual exploration of novel objects increases the levels of plasticity factors in the rat primary visual cortex. PeerJ 2018; 6:e5678. [PMID: 30370183 PMCID: PMC6202959 DOI: 10.7717/peerj.5678] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2018] [Accepted: 08/29/2018] [Indexed: 12/23/2022] Open
Abstract
Background Historically, the primary sensory areas of the cerebral cortex have been exclusively associated with the processing of a single sensory modality. Yet the presence of tactile responses in the primary visual (V1) cortex has challenged this view, leading to the notion that primary sensory areas engage in cross-modal processing, and that the associated circuitry is modifiable by such activity. To explore this notion, here we assessed whether the exploration of novel objects in the dark induces the activation of plasticity markers in the V1 cortex of rats. Methods Adult rats were allowed to freely explore for 20 min a completely dark box with four novel objects of different shapes and textures. Animals were euthanized either 1 (n = 5) or 3 h (n = 5) after exploration. A control group (n = 5) was placed for 20 min in the same environment, but without the objects. Frontal sections of the brains were submitted to immunohistochemistry to measure protein levels of egr-1 and c-fos, and phosphorylated calcium-dependent kinase (pCaKMII) in V1 cortex. Results The amount of neurons labeled with monoclonal antibodies against c-fos, egr-1 or pCaKMII increased significantly in V1 cortex after one hour of exploration in the dark. Three hours after exploration, the number of labeled neurons decreased to basal levels. Conclusions Our results suggest that non-visual exploration induces the activation of immediate-early genes in V1 cortex, which is suggestive of cross-modal processing in this area. Besides, the increase in the number of neurons labeled with pCaKMII may signal a condition promoting synaptic plasticity.
Collapse
Affiliation(s)
- Catia M Pereira
- Instituto Internacional de Neurociências de Natal Edmond e Lily Safra, Macaiba, RN, Brasil
| | - Marco Aurelio M Freire
- Programa de Pós-graduação em Saúde e Sociedade, Universidade do Estado do Rio Grande do Norte, Mossoró, RN, Brasil
| | - José R Santos
- Departamento de Biociências, Universidade Federal de Sergipe, Itabaiana, SE, Brasil
| | | | | | - Sharlene Santos
- Instituto do Cérebro, Universidade Federal do Rio Grande do Norte, Natal, RN, Brasil
| | - Antonio Pereira
- Faculdade de Engenharia Elétrica, Universidade Federal do Pará, Belém, PA, Brasil
| | - Sidarta Ribeiro
- Instituto do Cérebro, Universidade Federal do Rio Grande do Norte, Natal, RN, Brasil
| |
Collapse
|
9
|
Pattern of tyrosine hydroxylase expression during aging of mesolimbic pathway of the rat. J Chem Neuroanat 2018; 92:83-91. [DOI: 10.1016/j.jchemneu.2018.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 05/24/2018] [Accepted: 05/25/2018] [Indexed: 12/13/2022]
|
10
|
Deltamethrin Intranasal administration induces memory, emotional and tyrosine hydroxylase immunoreactivity alterations in rats. Brain Res Bull 2018; 142:297-303. [DOI: 10.1016/j.brainresbull.2018.08.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 07/24/2018] [Accepted: 08/11/2018] [Indexed: 02/04/2023]
|
11
|
Hinova-Palova DV, Edelstein L, Landzhov B, Minkov M, Malinova L, Hristov S, Denaro FJ, Alexandrov A, Kiriakova T, Brainova I, Paloff A, Ovtscharoff W. Topographical distribution and morphology of NADPH-diaphorase-stained neurons in the human claustrum. Front Syst Neurosci 2014; 8:96. [PMID: 24904317 PMCID: PMC4034338 DOI: 10.3389/fnsys.2014.00096] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 05/06/2014] [Indexed: 12/21/2022] Open
Abstract
We studied the topographical distribution and morphological characteristics of NADPH-diaphorase-positive neurons and fibers in the human claustrum. These neurons were seen to be heterogeneously distributed throughout the claustrum. Taking into account the size and shape of stained perikarya as well as dendritic and axonal characteristics, Nicotinamide adenine dinucleotide phosphate-diaphorase (NADPHd)-positive neurons were categorized by diameter into three types: large, medium and small. Large neurons ranged from 25 to 35 μm in diameter and typically displayed elliptical or multipolar cell bodies. Medium neurons ranged from 20 to 25 μm in diameter and displayed multipolar, bipolar and irregular cell bodies. Small neurons ranged from 14 to 20 μm in diameter and most often displayed oval or elliptical cell bodies. Based on dendritic characteristics, these neurons were divided into spiny and aspiny subtypes. Our findings reveal two populations of NADPHd-positive neurons in the human claustrum-one comprised of large and medium cells consistent with a projection neuron phenotype, the other represented by small cells resembling the interneuron phenotype as defined by previous Golgi impregnation studies.
Collapse
Affiliation(s)
- Dimka V Hinova-Palova
- Department of Anatomy, Histology, and Embryology, Medical University Sofia, Bulgaria
| | | | - Boycho Landzhov
- Department of Anatomy, Histology, and Embryology, Medical University Sofia, Bulgaria
| | - Minko Minkov
- Department of Anatomy and Histology, Medical University Varna, Bulgaria
| | - Lina Malinova
- Department of Anatomy, Histology, and Embryology, Medical University Sofia, Bulgaria
| | - Stanislav Hristov
- Department of Forensic Medicine and Deontology, Medical University Sofia, Bulgaria
| | - Frank J Denaro
- Department of Biology, Morgan State University Baltimore, MD, USA
| | - Alexandar Alexandrov
- Department of Forensic Medicine and Deontology, Medical University Sofia, Bulgaria
| | - Teodora Kiriakova
- Department of Forensic Medicine and Deontology, Medical University Sofia, Bulgaria
| | - Ilina Brainova
- Department of Forensic Medicine and Deontology, Medical University Sofia, Bulgaria
| | - Adrian Paloff
- Department of Anatomy, Histology, and Embryology, Medical University Sofia, Bulgaria
| | - Wladimir Ovtscharoff
- Department of Anatomy, Histology, and Embryology, Medical University Sofia, Bulgaria
| |
Collapse
|
12
|
Nogueira-Campos AA, Finamore DM, Imbiriba LA, Houzel JC, Franca JG. Distribution and morphology of nitrergic neurons across functional domains of the rat primary somatosensory cortex. Front Neural Circuits 2012; 6:57. [PMID: 23133407 PMCID: PMC3490138 DOI: 10.3389/fncir.2012.00057] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2012] [Accepted: 08/06/2012] [Indexed: 12/26/2022] Open
Abstract
The rat primary somatosensory cortex (S1) is remarkable for its conspicuous vertical compartmentalization in barrels and septal columns, which are additionally stratified in horizontal layers. Whereas excitatory neurons from each of these compartments perform different types of processing, the role of interneurons is much less clear. Among the numerous types of GABAergic interneurons, those producing nitric oxide (NO) are especially puzzling, since this gaseous messenger can modulate neural activity, synaptic plasticity, and neurovascular coupling. We used a quantitative morphological approach to investigate whether nitrergic interneurons, which might therefore be considered both as NO volume diffusers and as elements of local circuitry, display features that could relate to barrel cortex architecture. In fixed brain sections, nitrergic interneurons can be revealed by histochemical processing for NADPH-diaphorase (NADPHd). Here, the dendritic arbors of nitrergic neurons from different compartments of area S1 were 3D reconstructed from serial 200 μm thick sections, using 100x objective and the Neurolucida system. Standard morphological parameters were extracted for all individual arbors and compared across columns and layers. Wedge analysis was used to compute dendritic orientation indices. Supragranular (SG) layers displayed the highest density of nitrergic neurons, whereas layer IV contained nitrergic neurons with largest soma area. The highest nitrergic neuronal density was found in septa, where dendrites were previously characterized as more extense and ramified than in barrels. Dendritic arbors were not confined to the boundaries of the column nor layer of their respective soma, being mostly double-tufted and vertically oriented, except in SG layers. These data strongly suggest that nitrergic interneurons adapt their morphology to the dynamics of processing performed by cortical compartments.
Collapse
Affiliation(s)
- Anaelli A Nogueira-Campos
- Laboratório de Neurobiologia II, Programa de Neurobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro Rio de Janeiro, Brazil ; Departamento de Fisiologia, Instituto de Ciências Biológicas, Universidade Federal de Juiz de Fora Juiz de Fora, Brazil
| | | | | | | | | |
Collapse
|
13
|
Perrenoud Q, Geoffroy H, Gauthier B, Rancillac A, Alfonsi F, Kessaris N, Rossier J, Vitalis T, Gallopin T. Characterization of Type I and Type II nNOS-Expressing Interneurons in the Barrel Cortex of Mouse. Front Neural Circuits 2012; 6:36. [PMID: 22754499 PMCID: PMC3386492 DOI: 10.3389/fncir.2012.00036] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 05/31/2012] [Indexed: 12/11/2022] Open
Abstract
In the neocortex, neuronal nitric oxide (NO) synthase (nNOS) is essentially expressed in two classes of GABAergic neurons: type I neurons displaying high levels of expression and type II neurons displaying weaker expression. Using immunocytochemistry in mice expressing GFP under the control of the glutamic acid decarboxylase 67k (GAD67) promoter, we studied the distribution of type I and type II neurons in the barrel cortex and their expression of parvalbumin (PV), somatostatin (SOM), and vasoactive intestinal peptide (VIP). We found that type I neurons were predominantly located in deeper layers and expressed SOM (91.5%) while type II neurons were concentrated in layer II/III and VI and expressed PV (17.7%), SOM (18.7%), and VIP (10.2%). We then characterized neurons expressing nNOS mRNA (n = 42 cells) ex vivo, using whole-cell recordings coupled to single-cell reverse transcription-PCR and biocytin labeling. Unsupervised cluster analysis of this sample disclosed four classes. One cluster (n = 7) corresponded to large, deep layer neurons, displaying a high expression of SOM (85.7%) and was thus very likely to correspond to type I neurons. The three other clusters were identified as putative type II cells and corresponded to neurogliaform-like interneurons (n = 19), deep layer neurons expressing PV or SOM (n = 9), and neurons expressing VIP (n = 7). Finally, we performed nNOS immunohistochemistry on mouse lines in which GFP labeling revealed the expression of two specific developmental genes (Lhx6 and 5-HT3A). We found that type I neurons expressed Lhx6 but never 5-HT3A, indicating that they originate in the medial ganglionic eminence (MGE). Type II neurons expressed Lhx6 (63%) and 5-HT3A (34.4%) supporting their derivation either from the MGE or from the caudal ganglionic eminence (CGE) and the entopeduncular and dorsal preoptic areas. Together, our results in the barrel cortex of mouse support the view that type I neurons form a specific class of SOM-expressing neurons while type II neurons comprise at least three classes.
Collapse
Affiliation(s)
- Quentin Perrenoud
- Laboratoire de Neurobiologie, CNRS UMR 7637, ESPCI ParisTech Paris, France
| | | | | | | | | | | | | | | | | |
Collapse
|
14
|
Dittrich L, Heiss JE, Warrier DR, Perez XA, Quik M, Kilduff TS. Cortical nNOS neurons co-express the NK1 receptor and are depolarized by Substance P in multiple mammalian species. Front Neural Circuits 2012; 6:31. [PMID: 22679419 PMCID: PMC3367498 DOI: 10.3389/fncir.2012.00031] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2012] [Accepted: 05/06/2012] [Indexed: 11/17/2022] Open
Abstract
We have previously demonstrated that Type I neuronal nitric oxide synthase (nNOS)-expressing neurons are sleep-active in the cortex of mice, rats, and hamsters. These neurons are known to be GABAergic, to express Neuropeptide Y (NPY) and, in rats, to co-express the Substance P (SP) receptor NK1, suggesting a possible role for SP in sleep/wake regulation. To evaluate the degree of co-expression of nNOS and NK1 in the cortex among mammals, we used double immunofluorescence for nNOS and NK1 and determined the anatomical distribution in mouse, rat, and squirrel monkey cortex. Type I nNOS neurons co-expressed NK1 in all three species although the anatomical distribution within the cortex was species-specific. We then performed in vitro patch clamp recordings in cortical neurons in mouse and rat slices using the SP conjugate tetramethylrhodamine-SP (TMR-SP) to identify NK1-expressing cells and evaluated the effects of SP on these neurons. Bath application of SP (0.03–1 μM) resulted in a sustained increase in firing rate of these neurons; depolarization persisted in the presence of tetrodotoxin. These results suggest a conserved role for SP in the regulation of cortical sleep-active neurons in mammals.
Collapse
Affiliation(s)
- Lars Dittrich
- Biosciences Division, Center for Neuroscience, SRI International, Menlo Park CA, USA
| | | | | | | | | | | |
Collapse
|
15
|
Freire MAM, Faber J, Picanço-Diniz CW, Franca JG, Pereira A. Morphometric variability of nicotinamide adenine dinucleotide phosphate diaphorase neurons in the primary sensory areas of the rat. Neuroscience 2011; 205:140-53. [PMID: 22226695 DOI: 10.1016/j.neuroscience.2011.12.029] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2011] [Revised: 12/14/2011] [Accepted: 12/15/2011] [Indexed: 12/21/2022]
Abstract
Even though there is great regional variation in the distribution of inhibitory neurons in the mammalian isocortex, relatively little is known about their morphological differences across areal borders. To obtain a better understanding of particularities of inhibitory circuits in cortical areas that correspond to different sensory modalities, we investigated the morphometric differences of a subset of inhibitory neurons reactive to the enzyme nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) within the primary auditory (A1), somatosensory (S1), and visual (V1) areas of the rat. One hundred and twenty NADPH-d-reactive neurons from cortical layer IV (40 cells in each cortical area) were reconstructed using the Neurolucida system. We collected morphometric data on cell body area, dendritic field area, number of dendrites per branching order, total dendritic length, dendritic complexity (Sholl analysis), and fractal dimension. To characterize different cell groups based on morphology, we performed a cluster analysis based on the previously mentioned parameters and searched for correlations among these variables. Morphometric analysis of NADPH-d neurons allowed us to distinguish three groups of cells, corresponding to the three analyzed areas. S1 neurons have a higher morphological complexity than those found in both A1 and V1. The difference among these groups, based on cluster analysis, was mainly related to the size and complexity of dendritic branching. A principal component analysis (PCA) applied to the data showed that area of dendritic field and fractal dimension are the parameters mostly responsible for dataset variance among the three areas. Our results suggest that the nitrergic cortical circuitry of primary sensory areas of the rat is differentially specialized, probably reflecting peculiarities of both habit and behavior of the species.
Collapse
Affiliation(s)
- M A M Freire
- Laboratory of Neurodegeneration and Infection, João de Barros Barreto Universitary Hospital, Federal University of Pará, 66073-000 Belém, PA, Brazil
| | | | | | | | | |
Collapse
|
16
|
Freire MAM, Morya E, Faber J, Santos JR, Guimaraes JS, Lemos NAM, Sameshima K, Pereira A, Ribeiro S, Nicolelis MAL. Comprehensive analysis of tissue preservation and recording quality from chronic multielectrode implants. PLoS One 2011; 6:e27554. [PMID: 22096594 PMCID: PMC3212580 DOI: 10.1371/journal.pone.0027554] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 10/19/2011] [Indexed: 11/18/2022] Open
Abstract
Multielectrodes have been used with great success to simultaneously record the activity of neuronal populations in awake, behaving animals. In particular, there is great promise in the use of this technique to allow the control of neuroprosthetic devices by human patients. However, it is crucial to fully characterize the tissue response to the chronic implants in animal models ahead of the initiation of human clinical trials. Here we evaluated the effects of unilateral multielectrode implants on the motor cortex of rats weekly recorded for 1-6 months using several histological methods to assess metabolic markers, inflammatory response, immediate-early gene (IEG) expression, cytoskeletal integrity and apoptotic profiles. We also investigated the correlations between each of these features and firing rates, to estimate the impact of post-implant time on neuronal recordings. Overall, limited neuronal loss and glial activation were observed on the implanted sites. Reactivity to enzymatic metabolic markers and IEG expression were not significantly different between implanted and non-implanted hemispheres. Multielectrode recordings remained viable for up to 6 months after implantation, and firing rates correlated well to the histochemical and immunohistochemical markers. Altogether, our results indicate that chronic tungsten multielectrode implants do not substantially alter the histological and functional integrity of target sites in the cerebral cortex.
Collapse
Affiliation(s)
| | - Edgard Morya
- Clinical Neurophysiology Laboratory of the Associação Alberto Santos Dumont para Apoio a Pesquisa, Sírio Libanês Hospital, São Paulo/SP, Brazil
| | - Jean Faber
- Edmond and Lily Safra International Institute of Neuroscience of Natal, Natal/RN, Brazil
- Foundation Nanosciences and Clinatec/LETI/CEA, Grenoble, France
| | - Jose Ronaldo Santos
- Edmond and Lily Safra International Institute of Neuroscience of Natal, Natal/RN, Brazil
| | - Joanilson S. Guimaraes
- Edmond and Lily Safra International Institute of Neuroscience of Natal, Natal/RN, Brazil
| | - Nelson A. M. Lemos
- Edmond and Lily Safra International Institute of Neuroscience of Natal, Natal/RN, Brazil
| | - Koichi Sameshima
- Clinical Neurophysiology Laboratory of the Associação Alberto Santos Dumont para Apoio a Pesquisa, Sírio Libanês Hospital, São Paulo/SP, Brazil
- Department of Radiology, School of Medicine, University of São Paulo, São Paulo/SP, Brazil
| | - Antonio Pereira
- Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Sidarta Ribeiro
- Brain Institute, Federal University of Rio Grande do Norte, Natal, RN, Brazil
| | - Miguel A. L. Nicolelis
- Edmond and Lily Safra International Institute of Neuroscience of Natal, Natal/RN, Brazil
- Clinical Neurophysiology Laboratory of the Associação Alberto Santos Dumont para Apoio a Pesquisa, Sírio Libanês Hospital, São Paulo/SP, Brazil
- Center for Neuroengineering, Department of Neurobiology, Duke University Medical Center, Durham, North Carolina, United States of America
- Department of Biomedical Engineering, Duke University, Durham, North Carolina, United States of America
- Department of Psychological and Brain Sciences, Duke University, Durham, North Carolina, United States of America
| |
Collapse
|
17
|
Kubota Y, Shigematsu N, Karube F, Sekigawa A, Kato S, Yamaguchi N, Hirai Y, Morishima M, Kawaguchi Y. Selective coexpression of multiple chemical markers defines discrete populations of neocortical GABAergic neurons. ACTA ACUST UNITED AC 2011; 21:1803-17. [PMID: 21220766 DOI: 10.1093/cercor/bhq252] [Citation(s) in RCA: 178] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Whether neocortical γ-aminobutyric acid (GABA) cells are composed of a limited number of distinct classes of neuron, or whether they are continuously differentiated with much higher diversity, remains a contentious issue for the field. Most GABA cells of rat frontal cortex have at least 1 of 6 chemical markers (parvalbumin, calretinin, alpha-actinin-2, somatostatin, vasoactive intestinal polypeptide, and cholecystokinin), with each chemical class comprising several distinct neuronal subtypes having specific physiological and morphological characteristics. To better clarify GABAergic neuron diversity, we assessed the colocalization of these 6 chemical markers with corticotropin-releasing factor (CRF), neuropeptide Y (NPY), the substance P receptor (SPR), and nitric oxide synthase (NOS); these 4 additional chemical markers suggested to be expressed diversely or specifically among cortical GABA cells. We further correlated morphological and physiological characteristics of identified some chemical subclasses of inhibitory neurons. Our results reveal expression specificity of CRF, NPY, SPR, and NOS in morphologically and physiologically distinct interneuron classes. These observations support the existence of a limited number of functionally distinct subtypes of GABA cells in the neocortex.
Collapse
Affiliation(s)
- Yoshiyuki Kubota
- Division of Cerebral Circuitry, National Institute for Physiological Sciences, Okazaki 444-8787, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Freire MAM, Rocha EG, Oliveira JLF, Guimarães JS, Silveira LCL, Elston GN, Pereira A, Picanço-Diniz CW. Morphological variability of NADPH diaphorase neurons across areas V1, V2, and V3 of the common agouti. Brain Res 2009; 1318:52-63. [PMID: 20036219 DOI: 10.1016/j.brainres.2009.12.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2009] [Revised: 12/11/2009] [Accepted: 12/14/2009] [Indexed: 01/24/2023]
Abstract
Previous studies have shown a noticeable phenotypic diversity for pyramidal cells among cortical areas in the cerebral cortex. Both the extent and systematic nature of this variation suggests a correlation with particular aspects of cortical processing. Nevertheless, regional variations in the morphology of inhibitory cells have not been evaluated with the same detail. In the present study we performed a 3D morphometric analysis of 120 NADPH diaphorase (NADPH-d) type I neurons in the visual cortex of a South American Hystricomorph rodent, the diurnal agouti (Dasyprocta sp.). We found significant differences in morphology of NADPH-d type I neurons among visual cortical areas: cells became progressively larger and more branched from V1 to V2 and V3. Presumably, the specialized morphology of these cells is correlated with different sampling geometry and function. The data suggest that area-specific specializations of cortical inhibitory circuitry are also present in rodents.
Collapse
Affiliation(s)
- Marco Aurélio M Freire
- Lab. Neurodegeneração e Infecção, Hospital Universitário João de Barros Barreto, Universidade Federal do Pará, 66073-000 Belém, PA, Brazil
| | | | | | | | | | | | | | | |
Collapse
|
19
|
Freire MAM, Guimarães JS, Leal WG, Pereira A. Pain modulation by nitric oxide in the spinal cord. Front Neurosci 2009; 3:175-81. [PMID: 20011139 PMCID: PMC2751623 DOI: 10.3389/neuro.01.024.2009] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2009] [Accepted: 07/08/2009] [Indexed: 01/24/2023] Open
Abstract
Nitric oxide (NO) is a versatile messenger molecule first associated with endothelial relaxing effects. In the central nervous system (CNS), NO synthesis is primarily triggered by activation of N-methyl-D-aspartate (NMDA) receptors and has a Janus face, with both beneficial and harmful properties. There are three isoforms of the NO synthesizing enzyme nitric oxide synthase (NOS): neuronal (nNOS), endothelial (eNOS), and inducible nitric oxide synthase (iNOS), each one involved with specific events in the brain. In the CNS, nNOS is involved with modulation of synaptic transmission through long-term potentiation in several regions, including nociceptive circuits in the spinal cord. Here, we review the role played by NO on central pain sensitization.
Collapse
Affiliation(s)
- Marco Aurélio M Freire
- Edmond and Lily Safra International Institute of Neuroscience of Natal (ELS-IINN) Natal, RN, Brazil
| | | | | | | |
Collapse
|
20
|
Freire MAM, Tourinho SC, Guimarães JS, Oliveira JLF, Picanço-Diniz CW, Gomes-Leal W, Pereira A. Histochemical characterization, distribution and morphometric analysis of NADPH diaphorase neurons in the spinal cord of the agouti. Front Neuroanat 2008; 2:2. [PMID: 18958200 PMCID: PMC2525924 DOI: 10.3389/neuro.05.002.2008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Accepted: 05/08/2008] [Indexed: 01/12/2023] Open
Abstract
We evaluated the neuropil distribution of the enzymes NADPH diaphorase (NADPH-d) and cytochrome oxidase (CO) in the spinal cord of the agouti, a medium-sized diurnal rodent, together with the distribution pattern and morphometrical characteristics of NADPH-d reactive neurons across different spinal segments. Neuropil labeling pattern was remarkably similar for both enzymes in coronal sections: reactivity was higher in regions involved with pain processing. We found two distinct types of NADPH-d reactive neurons in the agouti's spinal cord: type I neurons had large, heavily stained cell bodies while type II neurons displayed relatively small and poorly stained somata. We concentrated our analysis on type I neurons. These were found mainly in the dorsal horn and around the central canal of every spinal segment, with a few scattered neurons located in the ventral horn of both cervical and lumbar regions. Overall, type I neurons were more numerous in the cervical region. Type I neurons were also found in the white matter, particularly in the ventral funiculum. Morphometrical analysis revealed that type I neurons located in the cervical region have dendritic trees that are more complex than those located in both lumbar and thoracic regions. In addition, NADPH-d cells located in the ventral horn had a larger cell body, especially in lumbar segments. The resulting pattern of cell body and neuropil distribution is in accordance with proposed schemes of segregation of function in the mammalian spinal cord.
Collapse
Affiliation(s)
- Marco Aurélio M Freire
- Laboratory of Functional Neuroanatomy, Institute of Biological Sciences, Federal University of Pará Belém, Brazil
| | | | | | | | | | | | | |
Collapse
|
21
|
|
22
|
Freire MAM, Oliveira RB, Picanço-Diniz CW, Pereira A. Differential effects of methylmercury intoxication in the rat's barrel field as evidenced by NADPH diaphorase histochemistry. Neurotoxicology 2006; 28:175-81. [PMID: 16930717 DOI: 10.1016/j.neuro.2006.06.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2006] [Revised: 06/20/2006] [Accepted: 06/22/2006] [Indexed: 10/24/2022]
Abstract
In the present study, we investigated the effects of mercury intoxication on the structure of the posteromedial barrel subfield (PMBSF) in the primary somatosensory cortex (SI) of adult rats, as revealed by histochemical reactivity to the enzyme NADPH diaphorase (NADPH-d). Enzymatic reactivity in the neuropil inside barrels was drastically reduced in intoxicated animals, suggesting that the synthesis and/or transport of the nitric oxide synthase enzyme can be altered in acute mercury intoxication. However, the cell bodies and dendrites of barrel neurons, also strongly reactive to the enzyme, were spared from the mercury's deleterious effects.
Collapse
Affiliation(s)
- Marco Aurélio M Freire
- Laboratory of Functional Neuroanatomy, Department of Morphology, Federal University of Pará, Belém 66075-900, PA, Brazil.
| | | | | | | |
Collapse
|
23
|
Rocha EG, Santiago LF, Freire MAM, Gomes-Leal W, Dias IA, Lent R, Houzel JC, Franca JG, Pereira A, Picanço-Diniz CW. Callosal axon arbors in the limb representations of the somatosensory cortex (SI) in the agouti (Dasyprocta primnolopha). J Comp Neurol 2006; 500:255-66. [PMID: 17111360 DOI: 10.1002/cne.21167] [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] [Indexed: 11/07/2022]
Abstract
The present report compares the morphology of callosal axon arbors projecting from and to the hind- or forelimb representations in the primary somatosensory cortex (SI) of the agouti (Dasyprocta primnolopha), a large, lisencephlic Brazilian rodent that uses forelimb coordination for feeding. Callosal axons were labeled after single pressure (n = 6) or iontophoretic injections (n = 2) of the neuronal tracer biotinylated dextran amine (BDA, 10 kD), either into the hind- (n = 4) or forelimb (n = 4) representations of SI, as identified by electrophysiological recording. Sixty-nine labeled axon fragments located across all layers of contralateral SI representations of the hindlimb (n = 35) and forelimb (n = 34) were analyzed. Quantitative morphometric features such as densities of branching points and boutons, segments length, branching angles, and terminal field areas were measured. Cluster analysis of these values revealed the existence of two types of axon terminals: Type I (46.4%), less branched and more widespread, and Type II (53.6%), more branched and compact. Both axon types were asymmetrically distributed; Type I axonal fragments being more frequent in hindlimb (71.9%) vs. forelimb (28.13%) representation, while most of Type II axonal arbors were found in the forelimb representation (67.56%). We concluded that the sets of callosal axon connecting fore- and hindlimb regions in SI are morphometrically distinct from each other. As callosal projections in somatosensory and motor cortices seem to be essential for bimanual interaction, we suggest that the morphological specialization of callosal axons in SI of the agouti may be correlated with this particular function.
Collapse
Affiliation(s)
- E G Rocha
- Laboratório de Neuroanatomia Funcional, Departamento de Morfologia-Universidade Federal do Pará, 66075-900 Belém, PA, Brasil
| | | | | | | | | | | | | | | | | | | |
Collapse
|