The Experts below are selected from a list of 234 Experts worldwide ranked by ideXlab platform
Jeanfrancois Bernard - One of the best experts on this subject based on the ideXlab platform.
-
gaba but not opioids mediates the anti hyperalgesic effects of 5 ht7 receptor activation in rats suffering from neuropathic pain
Neuropharmacology, 2012Co-Authors: F Viguier, Benoit Michot, Valerie Kayser, Jeanfrancois Bernard, Josemiguel Vela, Michel HamonAbstract:Among receptors mediating serotonin actions in pain control, the 5-HT(7)R is of special interest because it is expressed by primary afferent fibers and intrinsic GABAergic and opioidergic interneurons within the spinal dorsal horn. Herein, we investigated whether GABA and/or opioids contribute to 5-HT(7)R-mediated control of neuropathic pain caused by nerve ligation. Acute administration of 5-HT(7)R agonists (AS-19, MSD-5a, E-55888) was found to markedly reduce mechanical and thermal hyperalgesia in rats with unilateral constriction injury to the sciatic nerve (CCI-SN). In contrast, mechanical hypersensitivity caused by unilateral constriction injury to the infraorbital nerve was essentially unaffected by these ligands. Further characterization of the anti-hyperalgesic effect of 5-HT(7)R activation by the selective agonist E-55888 showed that it was associated with a decrease in IL-1s mRNA overexpression in ipsilateral L4-L6 dorsal root ganglia and lumbar dorsal horn in CCI-SN rats. In addition, E-55888 diminished CCI-SN-associated increase in c-Fos immunolabeling in superficial laminae of the lumbar dorsal horn and the locus coeruleus, but increased c-Fos immunolabeling in the nucleus tractus solitarius and the Parabrachial Area in both control and CCI-SN rats. When injected intrathecally (i.t.), bicuculline (3 μg i.t.), but neither phaclofen (5 μg i.t.) nor naloxone (10 μg i.t.), significantly reduced the anti-hyperalgesic effects of 5-HT(7)R activation (E-55888, 10 mg/kg s.c.) in CCI-SN rats. These data support the idea that 5-HT(7)R-mediated inhibitory control of neuropathic pain is underlain by excitation of GABAergic interneurons within the dorsal horn. In addition, 5-HT(7)R activation-induced c-Fos increase in the nucleus tractus solitarius and the Parabrachial Area suggests that supraspinal mechanisms might also be involved.
-
Pain Pathways and Parabrachial Circuits in the Rat
Experimental physiology, 2002Co-Authors: Caroline Gauriau, Jeanfrancois BernardAbstract:This review presents a schematic attempt to classify the major pain pathways, based on the results of recent studies in our laboratory, with a special emphasis on the Parabrachial system. Our view is based on results from experiments in the rat, using very small iontophoretic injections of anterograde tracers. As illustrated in this report, we have found a very dramatic difference between ascending projections originating from deep laminae compared with those arising from lamina I of the dorsal horn. We propose three main pain systems and discuss their functional-anatomical relationships. The first system is centred on the projection from deep laminae to three caudal reticular Areas - the lateral reticular nucleus (LRN), the subnucleus reticularis dorsalis (SRD) and the gigantocellular lateral paragigantocellular reticular nuclei (NGc) - and the Parabrachial internal lateral subnucleus (PBil). The second system is centred on the projection from lamina I to the ventral posterolateral nucleus (VPL), the ventral posteromedial (VPM), the posterior nuclear group (Po) and triangular posterior nucleus (PoT) of the thalamus. The third system is centred on the projection from lamina I to the lateral Parabrachial Area. We also present the four main projections from the latter Area to the extended amygdala, the hypothalamus, the periaqueductal grey matter (PAG), and the ventrolateral medulla (VLM), and their involvement in emotional and autonomic (homeostatic) aspects of pain. Experimental Physiology (2002) 87.2 , 251-258.
-
differential projections to the intralaminar and gustatory thalamus from the Parabrachial Area a pha l study in the rat
The Journal of Comparative Neurology, 1999Co-Authors: Hervé Bester, Luis Villanueva, Jean-marie Besson, Laurence Bourgeais, Jeanfrancois BernardAbstract:The organization of projections from the Parabrachial (PB) Area to the ventral posterior parvicellular (VPpc) "gustatory" and intralaminar nuclei of the thalamus was studied in the rat by using microinjections of Phaseolus vulgaris leucoagglutinin (PHA-L), into subregions of the PB Area. The present study is a follow-up of three former studies (Bernard et al. [1993] J. Comp. Neurol. 329:201-229; Alden et al. [1994] J. Comp. Neurol. 341:289-314; Bester et al. [1997a] J. Comp. Neurol. 383:245-281) that examined PB projections onto the amygdala, the bed nucleus of the stria terminalis, and the hypothalamus. Our data showed that (1) the region centered in the internal lateral PB subnucleus projects densely with a bilateral and symmetric pattern to the caudal portion of the paracentral and, to a lesser extent, to the adjacent portion of the central and parafascicular medial thalamic nuclei; (2) the mesencephalic PB region centered in the ventral lateral subnucleus and scattered neurons in the subjacent brachium conjunctivum project primarily, although diffusely, to the central medial thalamic nucleus. The third region includes two subgroups: (3a) the medial subgroup, including the medial, the waist Area, and the ventral lateral subnuclei of the pontine PB Area, projects bilaterally but with a weak ipsilateral predominance to the VPpc, terminals bearing large varicosities. Additionally, a diffuse projection with small varicosities spreads in the Area between the two VPpc nuclei and the central medial nucleus. (3b) The lateral subgroup, centered in the external medial subnucleus, projects with a contralateral predominance in the periphery of the VPpc nuclei, most terminals being located around the dorsomedial tip. It is suggested that the PB projections to the intralaminar nucleus could be involved in cortical limbic arousal processing in relation with nociceptive, (somatic, visceral, and intraoral) and gustatory aversive stimuli. The projection with large varicosities inside the VPpc could process gustatory discrimination.
-
Organization of efferent projections from the Parabrachial Area to the hypothalamus: a Phaseolus vulgaris‐leucoagglutinin study in the rat
The Journal of comparative neurology, 1997Co-Authors: Hervé Bester, Jean-marie Besson, Jeanfrancois BernardAbstract:The organization of projections from the Parabrachial (PB) Area to the hypothalamus was studied in the rat by using microinjections of Phaseolus vulgaris-leucoagglutinin (PHA-L) into subregions of the PB Area. The present study is a follow-up of two former studies (Bernard et al. [1993] J. Comp. Neurol. 329:201-229; Alden et al. [1994] J. Comp. Neurol. 341:289-314) that examined PB projections onto the amygdala and the bed nucleus of the stria terminalis. The results demonstrate that 1) the mesencephalic PB region, centered in the lateral portion of the superior lateral subnucleus projects extremely densely to almost the entire dorsomedial subdivision of the ipsilateral ventromedial hypothalamic nucleus; 2) the mesencephalic PB region, located in the medial portion of the superior lateral subnucleus and weakly overflowing into the rostralmost dorsal lateral pontine subnucleus, projects densely to the retrochiasmatic Area and, to a lesser extent, to the ipsilateral ventromedial nucleus of the hypothalamus; 3) the PB region, including the central lateral, a portion of the superior lateral, and the outer external lateral subnuclei, projects densely to the ipsilateral median, anteroventral, and periventricular preoptic hypothalamic nuclei and projects more weakly to the dorsal border of the paraventricular nucleus (PVN). No consistent projection was found in the magnocellular PVN. All of these PB regions also project diffusely to the dorsomedial Area and to a small tuberal subfornical hypothalamic Area. In addition, the medial half of the PB Area projects consistently to the posterior lateral hypothalamus. It is suggested that these pathways may be involved in aversive-defensive behavior, in autonomic and neuroendocrine aspects of pain, and in feeding and energy metabolism regulation. J. Comp. Neurol. 383:245-281, 1997. © 1997 Wiley-Liss, Inc.
-
organization of efferent projections from the Parabrachial Area to the hypothalamus a phaseolus vulgaris leucoagglutinin study in the rat
The Journal of Comparative Neurology, 1997Co-Authors: Hervé Bester, Jean-marie Besson, Jeanfrancois BernardAbstract:The organization of projections from the Parabrachial (PB) Area to the hypothalamus was studied in the rat by using microinjections of Phaseolus vulgaris-leucoagglutinin (PHA-L) into subregions of the PB Area. The present study is a follow-up of two former studies (Bernard et al. [1993] J. Comp. Neurol. 329:201-229; Alden et al. [1994] J. Comp. Neurol. 341:289-314) that examined PB projections onto the amygdala and the bed nucleus of the stria terminalis. The results demonstrate that 1) the mesencephalic PB region, centered in the lateral portion of the superior lateral subnucleus projects extremely densely to almost the entire dorsomedial subdivision of the ipsilateral ventromedial hypothalamic nucleus; 2) the mesencephalic PB region, located in the medial portion of the superior lateral subnucleus and weakly overflowing into the rostralmost dorsal lateral pontine subnucleus, projects densely to the retrochiasmatic Area and, to a lesser extent, to the ipsilateral ventromedial nucleus of the hypothalamus; 3) the PB region, including the central lateral, a portion of the superior lateral, and the outer external lateral subnuclei, projects densely to the ipsilateral median, anteroventral, and periventricular preoptic hypothalamic nuclei and projects more weakly to the dorsal border of the paraventricular nucleus (PVN). No consistent projection was found in the magnocellular PVN. All of these PB regions also project diffusely to the dorsomedial Area and to a small tuberal subfornical hypothalamic Area. In addition, the medial half of the PB Area projects consistently to the posterior lateral hypothalamus. It is suggested that these pathways may be involved in aversive-defensive behavior, in autonomic and neuroendocrine aspects of pain, and in feeding and energy metabolism regulation. J. Comp. Neurol. 383:245-281, 1997. © 1997 Wiley-Liss, Inc.
Jean-marie Besson - One of the best experts on this subject based on the ideXlab platform.
-
differential projections to the intralaminar and gustatory thalamus from the Parabrachial Area a pha l study in the rat
The Journal of Comparative Neurology, 1999Co-Authors: Hervé Bester, Luis Villanueva, Jean-marie Besson, Laurence Bourgeais, Jeanfrancois BernardAbstract:The organization of projections from the Parabrachial (PB) Area to the ventral posterior parvicellular (VPpc) "gustatory" and intralaminar nuclei of the thalamus was studied in the rat by using microinjections of Phaseolus vulgaris leucoagglutinin (PHA-L), into subregions of the PB Area. The present study is a follow-up of three former studies (Bernard et al. [1993] J. Comp. Neurol. 329:201-229; Alden et al. [1994] J. Comp. Neurol. 341:289-314; Bester et al. [1997a] J. Comp. Neurol. 383:245-281) that examined PB projections onto the amygdala, the bed nucleus of the stria terminalis, and the hypothalamus. Our data showed that (1) the region centered in the internal lateral PB subnucleus projects densely with a bilateral and symmetric pattern to the caudal portion of the paracentral and, to a lesser extent, to the adjacent portion of the central and parafascicular medial thalamic nuclei; (2) the mesencephalic PB region centered in the ventral lateral subnucleus and scattered neurons in the subjacent brachium conjunctivum project primarily, although diffusely, to the central medial thalamic nucleus. The third region includes two subgroups: (3a) the medial subgroup, including the medial, the waist Area, and the ventral lateral subnuclei of the pontine PB Area, projects bilaterally but with a weak ipsilateral predominance to the VPpc, terminals bearing large varicosities. Additionally, a diffuse projection with small varicosities spreads in the Area between the two VPpc nuclei and the central medial nucleus. (3b) The lateral subgroup, centered in the external medial subnucleus, projects with a contralateral predominance in the periphery of the VPpc nuclei, most terminals being located around the dorsomedial tip. It is suggested that the PB projections to the intralaminar nucleus could be involved in cortical limbic arousal processing in relation with nociceptive, (somatic, visceral, and intraoral) and gustatory aversive stimuli. The projection with large varicosities inside the VPpc could process gustatory discrimination.
-
Organization of efferent projections from the Parabrachial Area to the hypothalamus: a Phaseolus vulgaris‐leucoagglutinin study in the rat
The Journal of comparative neurology, 1997Co-Authors: Hervé Bester, Jean-marie Besson, Jeanfrancois BernardAbstract:The organization of projections from the Parabrachial (PB) Area to the hypothalamus was studied in the rat by using microinjections of Phaseolus vulgaris-leucoagglutinin (PHA-L) into subregions of the PB Area. The present study is a follow-up of two former studies (Bernard et al. [1993] J. Comp. Neurol. 329:201-229; Alden et al. [1994] J. Comp. Neurol. 341:289-314) that examined PB projections onto the amygdala and the bed nucleus of the stria terminalis. The results demonstrate that 1) the mesencephalic PB region, centered in the lateral portion of the superior lateral subnucleus projects extremely densely to almost the entire dorsomedial subdivision of the ipsilateral ventromedial hypothalamic nucleus; 2) the mesencephalic PB region, located in the medial portion of the superior lateral subnucleus and weakly overflowing into the rostralmost dorsal lateral pontine subnucleus, projects densely to the retrochiasmatic Area and, to a lesser extent, to the ipsilateral ventromedial nucleus of the hypothalamus; 3) the PB region, including the central lateral, a portion of the superior lateral, and the outer external lateral subnuclei, projects densely to the ipsilateral median, anteroventral, and periventricular preoptic hypothalamic nuclei and projects more weakly to the dorsal border of the paraventricular nucleus (PVN). No consistent projection was found in the magnocellular PVN. All of these PB regions also project diffusely to the dorsomedial Area and to a small tuberal subfornical hypothalamic Area. In addition, the medial half of the PB Area projects consistently to the posterior lateral hypothalamus. It is suggested that these pathways may be involved in aversive-defensive behavior, in autonomic and neuroendocrine aspects of pain, and in feeding and energy metabolism regulation. J. Comp. Neurol. 383:245-281, 1997. © 1997 Wiley-Liss, Inc.
-
organization of efferent projections from the Parabrachial Area to the hypothalamus a phaseolus vulgaris leucoagglutinin study in the rat
The Journal of Comparative Neurology, 1997Co-Authors: Hervé Bester, Jean-marie Besson, Jeanfrancois BernardAbstract:The organization of projections from the Parabrachial (PB) Area to the hypothalamus was studied in the rat by using microinjections of Phaseolus vulgaris-leucoagglutinin (PHA-L) into subregions of the PB Area. The present study is a follow-up of two former studies (Bernard et al. [1993] J. Comp. Neurol. 329:201-229; Alden et al. [1994] J. Comp. Neurol. 341:289-314) that examined PB projections onto the amygdala and the bed nucleus of the stria terminalis. The results demonstrate that 1) the mesencephalic PB region, centered in the lateral portion of the superior lateral subnucleus projects extremely densely to almost the entire dorsomedial subdivision of the ipsilateral ventromedial hypothalamic nucleus; 2) the mesencephalic PB region, located in the medial portion of the superior lateral subnucleus and weakly overflowing into the rostralmost dorsal lateral pontine subnucleus, projects densely to the retrochiasmatic Area and, to a lesser extent, to the ipsilateral ventromedial nucleus of the hypothalamus; 3) the PB region, including the central lateral, a portion of the superior lateral, and the outer external lateral subnuclei, projects densely to the ipsilateral median, anteroventral, and periventricular preoptic hypothalamic nuclei and projects more weakly to the dorsal border of the paraventricular nucleus (PVN). No consistent projection was found in the magnocellular PVN. All of these PB regions also project diffusely to the dorsomedial Area and to a small tuberal subfornical hypothalamic Area. In addition, the medial half of the PB Area projects consistently to the posterior lateral hypothalamus. It is suggested that these pathways may be involved in aversive-defensive behavior, in autonomic and neuroendocrine aspects of pain, and in feeding and energy metabolism regulation. J. Comp. Neurol. 383:245-281, 1997. © 1997 Wiley-Liss, Inc.
-
Parabrachial Area: electrophysiological evidence for an involvement in cold nociception.
Journal of neurophysiology, 1996Co-Authors: L. Menendez, Jean-marie Besson, Hervé Bester, Jeanfrancois BernardAbstract:1. Thirty-five percent of 120 neurons recorded extracellularly in the Parabrachial (PB) Area of anesthetized rats responded to a peripheral cold stimulus (0 degrees C). The cold-sensitive neurons were located in the lateral PB Area, and most of those exhibiting a strong response to cold stimuli were inside or in close vicinity to the Area receiving a high density of projections from superficial neurons of the dorsal horn. 2. The receptive fields for cold stimulation often were restricted to one or two parts of the body with a contralateral predominance for the limbs. No side predominance was observed for the face. 3. From a low spontaneous activity (10th percentile < median < 90th percentile: 0.1 < 1.5 < 5 Hz), the PB neurons responded to cold noxious stimuli (0 degree C water bath or waterjet, 20 s), without observable delay, with a sustained discharge. The mean maximal response to the stimulus was 16.1 +/- 1.2 Hz (mean +/- SE; n = 42). 4. About one-half (45%) of these cold-sensitive neurons were activat...
-
organization of the efferent projections from the pontine Parabrachial Area to the bed nucleus of the stria terminalis and neighboring regions a pha l study in the rat
The Journal of Comparative Neurology, 1994Co-Authors: Marie Alden, Jean-marie Besson, Jeanfrancois BernardAbstract:The organization of efferent projections from the pontine Parabrachial (pPB) Area to the forebrain rostral to the central nucleus of the amygdala (Ce) was studied in the rat by using microinjections of Phaseolus vulgaris leucoagglutinin (PHA-L), into subregions of the pPB Area. The present study is a follow-up of a former study (Bernard et al. [1993] J. Comp. Neurol. 329:201–229) which examines pPB projections onto the Ce. The results demonstrate that: (1) the pPB(m) region (the medial, the ventral lateral subnuclei and the waist Area) diffusely projects to the lateral division (BSTL) of the bed nucleus of the stria terminalis (BST), the Ce-BSTL continuum (including, the dorsal portion of substantia innominata, the ventral portion of globus pallidus, the fundus striatum, and the substriatal Area) and to a lesser extent the agranular insular cortex; (2) the pPB(1) region [the central lateral (pPBc1) and the outer portion of external lateral subnuclei] densely projects to the dorsal lateral subnucleus of BST (BSTdl); only the pPBcl subnucleus projects to the median, the anteroventral and the periventricular nuclei of the preoptic hypothalamus; and (3) the remaining pPB Area (the dorsal lateral, part of the external lateral and the external medial subnuclei) projects to the nucleus of horizontal limb of diagonal band but does not project onto the BST and the preoptic hypothalamus. It is suggested that the pPB(m)-BSTL “diffuse pathway” is mainly implicated in motivational and autonomic aspects of taste. The pPB(1)-BSTdl and hypothalamic “concentrated pathways” could be implicated in autonomic and nociceptive processes.
Andrew J Todd - One of the best experts on this subject based on the ideXlab platform.
-
The organisation of spinoParabrachial neurons in the mouse
Pain, 2015Co-Authors: Darren Cameron, Erika Polgar, Maria Gutierrez-mecinas, Maria Gomez-lima, Masahiko Watanabe, Andrew J ToddAbstract:The anterolateral tract (ALT), which originates from neurons in lamina I and the deep dorsal horn, represents a major ascending output through which nociceptive information is transmitted to brain Areas involved in pain perception. Although there is detailed quantitative information concerning the ALT in the rat, much less is known about this system in the mouse, which is increasingly being used for studies of spinal pain mechanisms because of the availability of genetically modified lines. The aim of this study was therefore to determine the extent to which information about the ALT in the rat can be extrapolated to the mouse. Our results suggest that as in the rat, most lamina I ALT projection neurons in the lumbar enlargement can be retrogradely labelled from the lateral Parabrachial Area, that the majority of these cells (∼ 90%) express the neurokinin 1 receptor (NK1r), and that these are larger than other NK1r-expressing neurons in this lamina. This means that many lamina I spinoParabrachial cells can be identified in NK1r-immunostained sections from animals that have not received retrograde tracer injections. However, we also observed certain species differences, in particular we found that many spinoParabrachial cells in laminae III and IV lack the NK1r, meaning that they cannot be identified based solely on the expression of this receptor. We also provide evidence that the majority of spinoParabrachial cells are glutamatergic and that some express substance P. These findings will be important for studies designed to unravel the complex neuronal circuitry that underlies spinal pain processing.
-
a quantitative study of brainstem projections from lamina i neurons in the cervical and lumbar enlargement of the rat
Brain Research, 2010Co-Authors: Erika Polgar, Lorna L Wright, Andrew J ToddAbstract:Lamina I of the rat spinal cord contains neurons that project to various brain Areas including thalamus, periaqueductal grey matter (PAG), lateral Parabrachial Area (LPb), caudal ventrolateral medulla and a region in dorsal medulla that includes the nucleus tractus solitarius and dorsal reticular nucleus. We have shown that spinothalamic lamina I neurons are infrequent in rat lumbar enlargement, where they constitute ∼ 5% of the estimated 400 projection neurons on each side of the L4 segment (Al-Khater and Todd, 2009). They are more numerous in cervical enlargement, but the total number of lamina I projection neurons in this region was not known. Here we have used paired injections of retrograde tracers into the brainstem to estimate the number of lamina I projection cells in the C7 segment. Our results suggest that there are ∼ 215 lamina I projection cells per side, and that spinothalamic cells therefore make up ∼ 42% of this population. The proportion of lamina I projection neurons labelled from PAG is higher in cervical than lumbar enlargement, while the proportion labelled from dorsal medulla is similar in the two regions. We also found that lamina I cells in L4 that project to the dorsal medulla are included in the population retrogradely labelled from LPb, thus confirming the estimate that there are around 400 lamina I projection cells in this segment.
-
Collateral projections of neurons in laminae I, III, and IV of rat spinal cord to thalamus, periaqueductal gray matter, and lateral Parabrachial Area
The Journal of Comparative Neurology, 2009Co-Authors: Khulood M. Al-khater, Andrew J ToddAbstract:Projection neurons in lamina I, together with those in laminae III–IV that express the neurokinin 1 receptor (NK1r), form a major route through which nociceptive information reaches the brain. Axons of these cells innervate various targets, including thalamus, periaqueductal gray matter (PAG), and lateral Parabrachial Area (LPb), and many cells project to more than one target. The aims of this study were to quantify projections from cervical enlargement to PAG and LPb, to determine the proportion of spinothalamic neurons at lumbar and cervical levels that were labelled from PAG and LPb, and to investigate morphological differences between projection populations. The C7 segment contained fewer lamina I spinoParabrachial cells than L4, but a similar number of spino-PAG cells. Virtually all spinothalamic lamina I neurons at both levels were labelled from LPb and between one-third and one-half from PAG. This suggests that significant numbers project to all three targets. Spinothalamic lamina I neurons differed from those labelled only from LPb in that they were generally larger, were more often multipolar, and (in cervical enlargement) had stronger NK1r immunoreactivity. Most lamina III/IV NK1r cells at both levels projected to LPb, but few were labelled from PAG. The great majority of these cells in C7 and over one-fourth of those in L4 were spinothalamic, and at each level some projected to both thalamus and LPb. These results confirm that neurons in these laminae have extensive collateral projections and suggest that different neuronal subpopulations in lamina I have characteristic patterns of supraspinal projection. J. Comp. Neurol. 515:629–646, 2009. © 2009 Wiley-Liss, Inc.
-
a quantitative and morphological study of projection neurons in lamina i of the rat lumbar spinal cord
European Journal of Neuroscience, 2003Co-Authors: R C Spike, Zita Puskar, D Andrew, Andrew J ToddAbstract:In the rat lumbar spinal cord the major supraspinal targets for lamina I projection neurons are the caudal ventrolateral medulla (CVLM), lateral Parabrachial Area (LPb) and periaqueductal grey matter (PAG). In this study we have estimated the number of lamina I neurons retrogradely labelled from each of these sites in the L4 segment, as well as the proportion that can be labelled by injecting different tracers into two separate sites. Our results suggest that this segment contains approximately 400 lamina I projection neurons on each side, and that approximately 85% of these can be labelled from either the CVLM or the LPb on the contralateral side. Around 120 lamina I cells in L4 project to the PAG, and over 90% of these cells can also be labelled from the CVLM or LPb. Most lamina I neurons projecting to CVLM or LPb are located in the contralateral dorsal horn, but in each case some cells were found to have bilateral projections. We also examined horizontal sections to investigate morphology and the expression of the neurokinin 1 (NK1) receptor in cells labelled from CVLM, LPb or PAG. There were no consistent morphological differences between these groups, however, while cells with strong or moderate NK1 receptor-immunostaining were labelled from LPb or CVLM, they seldom projected to the PAG. These results suggest that many lamina I cells project to more than one site in the brain and that those projecting to PAG may represent a distinct subclass of lamina I projection neuron.
-
Anatomy of primary afferents and projection neurones in the rat spinal dorsal horn with particular emphasis on substance P and the neurokinin 1 receptor.
Experimental physiology, 2002Co-Authors: Andrew J ToddAbstract:The dorsal horn of the spinal cord plays an important role in transmitting information from nociceptive primary afferent neurones to the brain; however, our knowledge of its neuronal and synaptic organisation is still limited. Nociceptive afferents terminate mainly in laminae I and II and some of these contain substance P. Many projection neurones are located in lamina I and these send axons to various parts of the brain, including the caudal ventrolateral medulla (CVLM), Parabrachial Area, periaqueductal grey matter and thalamus. The neurokinin 1 (NK1) receptor on which substance P acts is expressed by certain neurones in the dorsal horn, including approximately 80 % of lamina I projection neurones. There is also a population of large NK1 receptor-immunoreactive neurones with cell bodies in laminae III and IV which project to the CVLM and Parabrachial Area. It has been shown that the lamina III/IV NK1 receptor-immunoreactive projection neurones are densely and selectively innervated by substance P-containing primary afferent neurones, and there is evidence that these afferents also target lamina I projection neurones with the receptor. Both types of neurone are innervated by descending serotoninergic axons from the medullary raphe nuclei. The lamina III/IV neurones also receive numerous synapses from axons of local inhibitory interneurones which contain GABA and neuropeptide Y, and again this input shows some specificity since post-synaptic dorsal column neurones which also have cell bodies in laminae III and IV receive few contacts from neuropeptide Y-containing axons. These observations indicate that there are specific patterns of synaptic connectivity within the spinal dorsal horn.
Hervé Bester - One of the best experts on this subject based on the ideXlab platform.
-
Changes in tactile stimuli-induced behavior and c-Fos expression in the superficial dorsal horn and in Parabrachial nuclei after sciatic nerve crush
The Journal of comparative neurology, 2000Co-Authors: Hervé Bester, Simon Beggs, Clifford J. WoolfAbstract:Neurons in the superficial laminae of the dorsal horn are dominated by input from peripheral nociceptors. Following peripheral nerve injury, low threshold mechanoreceptive Aβ-fibers sprout from their normal termination site in laminae III/IV into laminae I–II and this structural reorganization may contribute to neuropathic tactile pain hypersensitivity. We have now investigated whether a sciatic nerve crush injury alters the behavioral response in rats to tactile stimuli and whether this is associated with a change in the pattern of c-Fos expression in the dorsal horn and the Parabrachial Area of the brainstem. Sciatic nerve crush resulted in a patchy but marked tactile allodynia manifesting first at 3 weeks and persisting for up to 52 weeks. C-Fos expression in the dorsal horn and Parabrachial region was never observed on brushing the skin of the sciatic nerve territory in animals with intact nerves, but was found after sciatic nerve crush with peripheral regeneration. We conclude that after nerve injury, low threshold mechanoreceptor fibers may play a major role in producing pain-related behavior by activating normally nociceptive-specific regions of the central nervous system such as the superficial laminae of the dorsal horn and the Parabrachial Area. J. Comp. Neurol. 428:45–61, 2000. © 2000 Wiley-Liss, Inc.
-
differential projections to the intralaminar and gustatory thalamus from the Parabrachial Area a pha l study in the rat
The Journal of Comparative Neurology, 1999Co-Authors: Hervé Bester, Luis Villanueva, Jean-marie Besson, Laurence Bourgeais, Jeanfrancois BernardAbstract:The organization of projections from the Parabrachial (PB) Area to the ventral posterior parvicellular (VPpc) "gustatory" and intralaminar nuclei of the thalamus was studied in the rat by using microinjections of Phaseolus vulgaris leucoagglutinin (PHA-L), into subregions of the PB Area. The present study is a follow-up of three former studies (Bernard et al. [1993] J. Comp. Neurol. 329:201-229; Alden et al. [1994] J. Comp. Neurol. 341:289-314; Bester et al. [1997a] J. Comp. Neurol. 383:245-281) that examined PB projections onto the amygdala, the bed nucleus of the stria terminalis, and the hypothalamus. Our data showed that (1) the region centered in the internal lateral PB subnucleus projects densely with a bilateral and symmetric pattern to the caudal portion of the paracentral and, to a lesser extent, to the adjacent portion of the central and parafascicular medial thalamic nuclei; (2) the mesencephalic PB region centered in the ventral lateral subnucleus and scattered neurons in the subjacent brachium conjunctivum project primarily, although diffusely, to the central medial thalamic nucleus. The third region includes two subgroups: (3a) the medial subgroup, including the medial, the waist Area, and the ventral lateral subnuclei of the pontine PB Area, projects bilaterally but with a weak ipsilateral predominance to the VPpc, terminals bearing large varicosities. Additionally, a diffuse projection with small varicosities spreads in the Area between the two VPpc nuclei and the central medial nucleus. (3b) The lateral subgroup, centered in the external medial subnucleus, projects with a contralateral predominance in the periphery of the VPpc nuclei, most terminals being located around the dorsomedial tip. It is suggested that the PB projections to the intralaminar nucleus could be involved in cortical limbic arousal processing in relation with nociceptive, (somatic, visceral, and intraoral) and gustatory aversive stimuli. The projection with large varicosities inside the VPpc could process gustatory discrimination.
-
Organization of efferent projections from the Parabrachial Area to the hypothalamus: a Phaseolus vulgaris‐leucoagglutinin study in the rat
The Journal of comparative neurology, 1997Co-Authors: Hervé Bester, Jean-marie Besson, Jeanfrancois BernardAbstract:The organization of projections from the Parabrachial (PB) Area to the hypothalamus was studied in the rat by using microinjections of Phaseolus vulgaris-leucoagglutinin (PHA-L) into subregions of the PB Area. The present study is a follow-up of two former studies (Bernard et al. [1993] J. Comp. Neurol. 329:201-229; Alden et al. [1994] J. Comp. Neurol. 341:289-314) that examined PB projections onto the amygdala and the bed nucleus of the stria terminalis. The results demonstrate that 1) the mesencephalic PB region, centered in the lateral portion of the superior lateral subnucleus projects extremely densely to almost the entire dorsomedial subdivision of the ipsilateral ventromedial hypothalamic nucleus; 2) the mesencephalic PB region, located in the medial portion of the superior lateral subnucleus and weakly overflowing into the rostralmost dorsal lateral pontine subnucleus, projects densely to the retrochiasmatic Area and, to a lesser extent, to the ipsilateral ventromedial nucleus of the hypothalamus; 3) the PB region, including the central lateral, a portion of the superior lateral, and the outer external lateral subnuclei, projects densely to the ipsilateral median, anteroventral, and periventricular preoptic hypothalamic nuclei and projects more weakly to the dorsal border of the paraventricular nucleus (PVN). No consistent projection was found in the magnocellular PVN. All of these PB regions also project diffusely to the dorsomedial Area and to a small tuberal subfornical hypothalamic Area. In addition, the medial half of the PB Area projects consistently to the posterior lateral hypothalamus. It is suggested that these pathways may be involved in aversive-defensive behavior, in autonomic and neuroendocrine aspects of pain, and in feeding and energy metabolism regulation. J. Comp. Neurol. 383:245-281, 1997. © 1997 Wiley-Liss, Inc.
-
organization of efferent projections from the Parabrachial Area to the hypothalamus a phaseolus vulgaris leucoagglutinin study in the rat
The Journal of Comparative Neurology, 1997Co-Authors: Hervé Bester, Jean-marie Besson, Jeanfrancois BernardAbstract:The organization of projections from the Parabrachial (PB) Area to the hypothalamus was studied in the rat by using microinjections of Phaseolus vulgaris-leucoagglutinin (PHA-L) into subregions of the PB Area. The present study is a follow-up of two former studies (Bernard et al. [1993] J. Comp. Neurol. 329:201-229; Alden et al. [1994] J. Comp. Neurol. 341:289-314) that examined PB projections onto the amygdala and the bed nucleus of the stria terminalis. The results demonstrate that 1) the mesencephalic PB region, centered in the lateral portion of the superior lateral subnucleus projects extremely densely to almost the entire dorsomedial subdivision of the ipsilateral ventromedial hypothalamic nucleus; 2) the mesencephalic PB region, located in the medial portion of the superior lateral subnucleus and weakly overflowing into the rostralmost dorsal lateral pontine subnucleus, projects densely to the retrochiasmatic Area and, to a lesser extent, to the ipsilateral ventromedial nucleus of the hypothalamus; 3) the PB region, including the central lateral, a portion of the superior lateral, and the outer external lateral subnuclei, projects densely to the ipsilateral median, anteroventral, and periventricular preoptic hypothalamic nuclei and projects more weakly to the dorsal border of the paraventricular nucleus (PVN). No consistent projection was found in the magnocellular PVN. All of these PB regions also project diffusely to the dorsomedial Area and to a small tuberal subfornical hypothalamic Area. In addition, the medial half of the PB Area projects consistently to the posterior lateral hypothalamus. It is suggested that these pathways may be involved in aversive-defensive behavior, in autonomic and neuroendocrine aspects of pain, and in feeding and energy metabolism regulation. J. Comp. Neurol. 383:245-281, 1997. © 1997 Wiley-Liss, Inc.
-
Parabrachial Area: electrophysiological evidence for an involvement in cold nociception.
Journal of neurophysiology, 1996Co-Authors: L. Menendez, Jean-marie Besson, Hervé Bester, Jeanfrancois BernardAbstract:1. Thirty-five percent of 120 neurons recorded extracellularly in the Parabrachial (PB) Area of anesthetized rats responded to a peripheral cold stimulus (0 degrees C). The cold-sensitive neurons were located in the lateral PB Area, and most of those exhibiting a strong response to cold stimuli were inside or in close vicinity to the Area receiving a high density of projections from superficial neurons of the dorsal horn. 2. The receptive fields for cold stimulation often were restricted to one or two parts of the body with a contralateral predominance for the limbs. No side predominance was observed for the face. 3. From a low spontaneous activity (10th percentile < median < 90th percentile: 0.1 < 1.5 < 5 Hz), the PB neurons responded to cold noxious stimuli (0 degree C water bath or waterjet, 20 s), without observable delay, with a sustained discharge. The mean maximal response to the stimulus was 16.1 +/- 1.2 Hz (mean +/- SE; n = 42). 4. About one-half (45%) of these cold-sensitive neurons were activat...
J.m. Besson - One of the best experts on this subject based on the ideXlab platform.
-
The Parabrachial Area: electrophysiological evidence for an involvement in visceral nociceptive processes
Journal of neurophysiology, 1994Co-Authors: Jeanfrancois Bernard, G. F. Huang, J.m. BessonAbstract:1. Neurons (n = 142) were recorded with extracellular micropipettes in the Parabrachial (PB) Area, in the anesthetized rat, some of them being antidromically driven from the centralis nucleus of th...
-
Efferent projections from the external Parabrachial Area to the forebrain: a Phaseolus vulgaris leucoagglutinin study in the rat.
Neuroscience letters, 1991Co-Authors: Jeanfrancois Bernard, J. Carroué, J.m. BessonAbstract:Small iontophoretic applications of Phaseolus vulgaris leucoagglutinin (PHA-L) were used to study the ascending efferent projections in the rat from the external Parabrachial (PBe) Area (i.e. external lateral (PBel) and external medial (PBem) subnuclei). It was found that fibers of the caudal two third of PBe project mainly to nucleus centralis of the amygdala (Ce) with a precise pattern: the PBel subnuclei mainly project to the caudomedial subdivision of the Ce and the PBem subnuclei mainly project to the rostrolateral subdivision of the Ce. Another dense and common projection of both subnuclei was found in the ventral pallidal Area adjacent to the Ce. This study delineates and extends the terminal Area of the spino(trigemino)-ponto-amygdaloid nociceptive pathway demonstrated by our previous studies.
