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Liang H, Schofield E, Paxinos G. Imaging Serotonergic Fibers in the Mouse Spinal Cord Using the CLARITY/CUBIC Technique. J Vis Exp 2016:53673. [PMID: 26967767 DOI: 10.3791/53673] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Long descending fibers to the spinal cord are essential for locomotion, pain perception, and other behaviors. The fiber termination pattern in the spinal cord of the majority of these fiber systems have not been thoroughly investigated in any species. Serotonergic fibers, which project to the spinal cord, have been studied in rats and opossums on histological sections and their functional significance has been deduced based on their fiber termination pattern in the spinal cord. With the development of CLARITY and CUBIC techniques, it is possible to investigate this fiber system and its distribution in the spinal cord, which is likely to reveal previously unknown features of serotonergic supraspinal pathways. Here, we provide a detailed protocol for imaging the serotonergic fibers in the mouse spinal cord using the combined CLARITY and CUBIC techniques. The method involves perfusion of a mouse with a hydrogel solution and clarification of the tissue with a combination of clearing reagents. Spinal cord tissue was cleared in just under two weeks, and the subsequent immunofluorescent staining against serotonin was completed in less than ten days. With a multi-photon fluorescent microscope, the tissue was scanned and a 3D image was reconstructed using Osirix software.
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Affiliation(s)
- Huazheng Liang
- Brain Structure and Function Group, Neuroscience Research Australia; School of Medical Sciences, The University of New South Wales;
| | - Emma Schofield
- Brain Structure and Function Group, Neuroscience Research Australia
| | - George Paxinos
- Brain Structure and Function Group, Neuroscience Research Australia; School of Medical Sciences, The University of New South Wales
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Liang H, Wang S, Francis R, Whan R, Watson C, Paxinos G. Distribution of raphespinal fibers in the mouse spinal cord. Mol Pain 2015; 11:42. [PMID: 26173454 PMCID: PMC4502924 DOI: 10.1186/s12990-015-0046-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Accepted: 07/03/2015] [Indexed: 12/13/2022] Open
Abstract
Background Serotonergic raphespinal neurons and their fibers have been mapped in large mammals, but the non-serotonergic ones have not been studied, especially in the mouse. The present study aimed to investigate the termination pattern of fibers arising from the hindbrain raphe and reticular nuclei which also have serotonergic neurons by injecting the anterograde tracer BDA into them. Results We found that raphespinal fibers terminate in both the dorsal and ventral horns in addition to lamina 10. There is a shift of the fibers in the ventral horn towards the dorsal and lateral part of the gray matter. Considerable variation in the termination pattern also exists between raphe nuclei with raphe magnus having more fibers terminating in the dorsal horn. Fibers from the adjacent gigantocellular reticular nucleus show similar termination pattern as those from the raphe nuclei with slight difference. Immunofluorescence staining showed that raphespinal fibers were heterogeneous and serotoninergic fibers were present in all laminae but mainly in laminae 1, 2, medial lamina 8, laminae 9 and 10. Surprisingly, immunofluorescence staining on clarified spinal cord tissue revealed that serotoninergic fibers formed bundles regularly in a short distance along the rostrocaudal axis in the medial part of the ventral horn and they extended towards the lateral motor neuron column area. Conclusion Serotonergic and non-serotonergic fibers arising from the hindbrain raphe and reticular nuclei had similar termination pattern in the mouse spinal cord with subtle difference. The present study provides anatomical foundation for the multiple roles raphe and adjacent reticular nuclei play. Electronic supplementary material The online version of this article (doi:10.1186/s12990-015-0046-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Huazheng Liang
- Neuroscience Research Australia, 139 Barker Street, Randwick, NSW, 2031, Australia. .,School of Medical Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Shaoshi Wang
- Department of Neurology, Branch of Shanghai First People's Hospital, Shanghai, 200081, China.
| | - Richard Francis
- Biomedical Imaging Facility, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Renee Whan
- Biomedical Imaging Facility, The University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Charles Watson
- Health Sciences Dean Research, Faculty of Health Sciences, Curtin University, Shenton Park Campus, Perth, WA, 6102, Australia.
| | - George Paxinos
- Neuroscience Research Australia, 139 Barker Street, Randwick, NSW, 2031, Australia. .,School of Medical Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia.
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Stornetta RL, McQuiston TJ, Guyenet PG. GABAergic and glycinergic presympathetic neurons of rat medulla oblongata identified by retrograde transport of pseudorabies virus and in situ hybridization. J Comp Neurol 2005; 479:257-70. [PMID: 15457502 DOI: 10.1002/cne.20332] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Electron microscopy suggests that up to half the synaptic input to sympathetic preganglionic neurons (SPGNs) is GABAergic or glycinergic. A proportion of this input is suspected to originate from neurons located within the medulla oblongata. The present study provides definitive evidence for the existence of these supraspinal presympathetic (PS) neurons with inhibitory phenotypes. PS neurons were identified by retrograde trans-synaptic migration of pseudorabies virus (PRV) injected into the adrenal gland. GABAergic or glycinergic cell bodies were identified by the presence of glutamate decarboxylase (GAD)-67 mRNA or glycine transporter (GlyT)-2 mRNA detected with in situ hybridization (ISH). Neither GABAergic nor glycinergic PS neurons were tyrosine hydroxylase (TH)-immunoreactive (ir). GABAergic PS neurons were located within the ventral gigantocellular nucleus, gigantocellular nucleus alpha, and medial reticular formation, mostly medial to the TH-ir PS neurons. About 30% of GABAergic PS neurons were serotonergic cells located in the raphe pallidus (RPa) and parapyramidal region (PPyr). Glycinergic PS neurons had the same general distribution as the GABAergic cells, except that no glycinergic neurons were located in the RPa or PPyr and none were serotonergic. PRV immunohistochemistry combined with ISH for both GlyT2 and GAD-67 mRNAs showed that at least 63% of midline medulla GABAergic PS neurons were also glycinergic and 76% of glycinergic PS neurons were GABAergic. In conclusion, the rostral ventromedial medulla contains large numbers of GABAergic and glycinergic neurons that innervate adrenal gland SPGNs. Over half of these PS neurons may release both transmitters. The physiological role of this medullary inhibitory input remains to be explored.
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Affiliation(s)
- Ruth L Stornetta
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA.
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Abstract
1. In a search for sympathetic premotor neurons subserving thermoregulatory functions, medullary raphé-spinal neurons were studied in urethane-anaesthetized, artificially ventilated, paralysed rats. Extracellular unit recordings were made from a region previously shown to drive the sympathetic supplies to tail vessels and brown adipose tissue. Neurons that were antidromically activated by stimulation across the intermediate region of the upper lumbar cord (the origin of the tail sympathetic outflow) were selected for study. 2. Non-noxious cooling stimuli were delivered to the animal's shaved trunk by circulating cold instead of warm water through a water jacket. Cooling increased the activity of 21 out of 76 raphé-spinal neurons by 1.0 +/- 0.2 spikes x s(-1) degrees C(-1) for falls in skin temperature of 3-5 degrees C below a threshold of 35.0 +/- 0.6 degrees C. Their responses followed skin temperature in a graded manner, and did so whether or not there was any change in core (rectal) temperature. 3. Indirect observations suggested that seven of the neurons that were activated by skin cooling were also activated by falls in core temperature (by 2.1 +/- 0.7 spikes x s(-1) x degrees C(-1) below a threshold of 36.1 +/- 0.7 degrees C), while the remainder were unaffected by core cooling. 4. An additional 7/76 raphé-spinal neurons showed evidence of inhibition (activity reduced by 2.1 +/- 0.5 spikes x s(-1) x degrees C(-1)) when the trunk skin was cooled. 5. Cold-activated raphé-spinal neurons were found in the nuclei raphé magnus and pallidus, centred at the level of the caudal part of the facial nucleus. Their spinal axons conducted at velocities between 3.4 and 29 m x s(-1) (median 6.8). 6. Drug-induced rises in arterial pressure partially inhibited the discharge of 6/14 cold-activated raphé-spinal neurons. Weak-to-moderate cardiac modulation (10-70 %) was present in arterial pulse-triggered histograms of the activity of 11/21 cold-activated raphé-spinal neurons, and 6/6 showed evidence of ventilatory modulation (two strongly, four weakly) in pump-triggered histograms. 7. Raphé-spinal neurons responded to cooling in the absence of any change in the electroencephalogram pattern (6/6 neurons). 8. Most cold-activated raphé-spinal neurons responded to noxious tail pinch (13/21 inhibited, 6/21 excited), as did most thermally unresponsive raphé-spinal cells in the same region (19/41 excited, 9/41 inhibited). 9. It is suggested that these cold-activated raphé-spinal neurons may constitute a premotor pathway that drives sympathetically mediated cold defences, such as cutaneous vasoconstriction or thermogenesis. The data are consistent with the hypothesis that a brainstem reflex, with additional descending input signalling body core temperature, may mediate autonomic responses to environmental cooling.
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Affiliation(s)
- J A Rathner
- Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Victoria 3010, Australia
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Meng XW, Budra B, Skinner K, Ohara P, Fields H. Noradrenergic input to nociceptive modulatory neurons in the rat rostral ventromedial medulla. J Comp Neurol 1997. [DOI: 10.1002/(sici)1096-9861(19970120)377:3<381::aid-cne6>3.0.co;2-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Woch G, Davies RO, Pack AI, Kubin L. Behaviour of raphe cells projecting to the dorsomedial medulla during carbachol-induced atonia in the cat. J Physiol 1996; 490 ( Pt 3):745-58. [PMID: 8683472 PMCID: PMC1158711 DOI: 10.1113/jphysiol.1996.sp021182] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
1. The activity of most brainstem serotonergic cells is suppressed during sleep, particularly the rapid eye movement (REM) phase. Thus, they may play a major role in state-dependent changes in CNS functioning. Our main goal was to search for medullary raphe cells having axonal branches in the region of the hypoglossal (XII) motor nucleus and assess their behaviour during the atonia produced by microinjections of a cholinergic agonist, carbachol, into the dorsal pontine tegmentum. In chronic animals, such microinjections evoke a desynchronized sleep-like state similar to natural REM sleep; in decerebrate animals, they produce eye movements and a motor suppression similar to the postural atonia of REM sleep. 2. In decerebrate, paralysed, vagotomized and artificially ventilated cats, we recorded extracellularly from medullary raphe cells antidromically activated from the XII nucleus region. Forty-five cells recorded in the raphe obscurus and pallidus nuclei were antidromically activated with latencies characteristic of non-myelinated fibres (4.4-42.0 ms). For thirty-three of the forty-five cells, we found one or more axonal branches within or just below the XII nucleus. The remaining twelve cells, in addition to the XII nucleus, had axonal ramifications in the medial nucleus of the solitary tract (NTS) and/or the dorsal motor nucleus of the vagus (DMV). 3. A subset of fourteen spontaneously active cells with identified axonal projections were held long enough to be recorded during the carbachol-induced atonia, and eight of these also during the subsequent recovery and a systemic administration of the serotonergic 1A receptor agonist (+/-)8-hydroxy-2-(di-N-propylamino)tetrealin hydrobromide (8-OH-DPAT). All but one were suppressed during the atonia in parallel to the suppression of XII, phrenic and postural nerve activities (firing rate, 1.3 +/- 0.7 Hz before and 0.1 +/- 0.2 Hz after carbachol (means +/- S.D.)). Following the recovery from the atonia, the firing rates of the eight cells increased to the pre-carbachol level (1.6 +/- 1.0 Hz). Subsequently, all were silenced by 8-OH-DPAT. 4. These cells fulfil most physiological criteria for serotonergic cells and have the potential to modulate, in a state-dependent manner, activities in the motor XII nucleus, visceral sensory NTS, and DMV. The decrements in serotonergic neuronal activity that occur during the carbachol-induced atonia suggest that a similar withdrawal of serotonergic input may occur during REM sleep and contribute to the characteristic reductions in upper airway motor tone.
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Affiliation(s)
- G Woch
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104-4283, USA
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Guyenet PG, Koshiya N, Huangfu D, Baraban SC, Stornetta RL, Li YW. Role of medulla oblongata in generation of sympathetic and vagal outflows. PROGRESS IN BRAIN RESEARCH 1996; 107:127-44. [PMID: 8782517 DOI: 10.1016/s0079-6123(08)61862-2] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- P G Guyenet
- Department of Pharmacology, University of Virginia Health Sciences Center, Charlottesville 22908, USA
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Gilbey MP, Futuro-Neto HA, Zhou SY. Respiratory-related discharge patterns of caudal raphe neurones projecting to the upper thoracic spinal cord in the rat. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1995; 50:263-73. [PMID: 7714321 DOI: 10.1016/0165-1838(94)00097-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Sympathetic activity is modulated by central respiratory drive. Bulbospinal neurones arising in the ventrolateral medulla and A5 region probably contribute to this modulation. In the present investigation the involvement of caudal raphe-spinal neurones in relaying respiratory-related inputs to sympathetic preganglionic neurones was investigated. Experiments were carried out on anaesthetized, vagotomized, paralysed and artificially ventilated rats. Extracellular recordings were made from the cell bodies of 53 caudal raphe neurones activated antidromically by stimulating the spinal cord between T1 and T3. The axonal conduction velocities ranged from 0.7-9.1 m/s (median = 3.8 m/s). Thirty-six of 53 neurones (consisting of neurones with on-going activity and quiescent neurones activated with glutamate) were held long enough for detailed analysis. Of those recorded 26 were in the region of raphe obscurus, nine in raphe pallidus and one in raphe magnus. Twenty-five of 36 neurons had firing patterns related to phrenic nerve discharge. Of the four firing patterns defined: seven neurones had the highest probability of firing during inspiration (inspiratory-related), 10 neurones had the highest probability of firing during expiration (expiratory-related), 3 had the highest probability of firing during post-inspiration (post-inspiratory-related) and 5 had lowest levels of firing during early- and post-inspiratory phases (early and post-inspiratory depressed). Of 27 neurones with axonal projections through or to the region of the intermediolateral cell column in the upper thoracic cord 19 had a respiratory-related discharge pattern. For respiratory-modulated neurones with on-going activity the median of the modal inter-spike intervals was 0.08 s. None of the neurones had an ECG-related firing pattern. The findings of this study also indicate a species difference between rats and cats regarding the physiological properties of some raphe-spinal neurones; i.e., an absence of ECG-related activity in the rats. The characteristics of the neurones recorded in this study are not those of 'typical' 5-HT-containing neurones with reference to axonal conduction velocities and discharge characteristics.
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Affiliation(s)
- M P Gilbey
- Department of Physiology, Royal Free Hospital School of Medicine, London, UK
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Allen GV, Cechetto DF. Serotoninergic and nonserotoninergic neurons in the medullary raphe system have axon collateral projections to autonomic and somatic cell groups in the medulla and spinal cord. J Comp Neurol 1994; 350:357-66. [PMID: 7533797 DOI: 10.1002/cne.903500303] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Fluorescent double retrograde-tracing studies combined with fluorescent immunostaining for serotonin were carried out to determine the potential patterns of divergence in axonal projections to autonomic and somatic motor sites from medullary raphe and parapyramidal neurons. Injections (20-60 nl) of combinations of fluorescent retrograde tracers (Fast Blue, fluoro-gold, green latex microspheres, Diamidino Yellow) were made into the intermediolateral cell column (IML) of the spinal cord and the brainstem lateral tegmental field or ventral horn of the lumbar spinal cord of male Wistar rats. The animals were perfused after a 7-10-day survival period, and the brains were removed, sectioned (50 microns), and immunostained for serotonin. Following injections of different retrograde-tracer substances into the IML of the thoracic cord and the ventral horn of the lumbar cord, 36% of the neurons with axon collateral projections to the IML and the lumbar ventral horn were serotoninergic. Following injections of different retrograde-tracer substances into the IML and the lateral tegmental field, 26% of the neurons with axon collateral projections to the IML and the lateral tegmental field were serotoninergic. Many of the medullary neurons with projections to the lateral tegmental field and the lumbar cord were located dorsal and lateral to those neurons with projections to the IML. The results indicate that serotoninergic and nonserotoninergic neurons of the midline raphe system and parapyramidal region have axon collateral branches to the IML and the lateral tegmental field or the IML and the lumbar ventral horn. These projection neurons may form the anatomical substrate for the integration of autonomic and somatic motor activity.
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Affiliation(s)
- G V Allen
- Dalhousie University, Department of Anatomy and Neurobiology, Halifax, Nova Scotia, Canada
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Yates BJ, Goto T, Bolton PS. Responses of neurons in the caudal medullary raphe nuclei of the cat to stimulation of the vestibular nerve. Exp Brain Res 1992; 89:323-32. [PMID: 1623976 DOI: 10.1007/bf00228248] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In the decerebrate cat, recordings were made from neurons in the caudal medullary raphe nuclei to determine if they responded to electrical stimulation of the vestibular nerve and thus might participate in vestibulosympathetic reflexes. Many of these cells projected to the upper thoracic spinal cord. The majority (20/28) of raphespinal neurons with conduction velocities between 1 and 4 m/s received vestibular inputs; 13 of the 20 were inhibited, and 7 were excited. Since many raphespinal neurons with similar slow conduction velocities are involved in the control of sympathetic outflow, as well as in other functions, these cells could potentially relay vestibular signals to sympathetic preganglionic neurons. The onset latency of the vestibular effects was long (median of 15 ms), indicating the inputs were polysynaptic. In addition, 34 of 42 raphespinal neurons with more rapid conduction velocities (6-78 m/s) also received long-latency (median of 10 ms) labyrinthine inputs; 26 were excited and 8 were inhibited. Although little is known about these rapidly-conducting cells, they do not appear to be involved in autonomic control, suggesting that the function of vestibular inputs to raphe neurons is not limited to production of vestibulosympathetic reflexes. One hypothesis is that raphe neurons are also involved in modulating the gain of vestibulocollic and vestibulospinal reflexes; this possibility remains to be tested.
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Affiliation(s)
- B J Yates
- Laboratory of Neurophysiology, Rockefeller University, New York, NY 10021
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Bereiter DA. Partial transection of the ipsilateral cervical spinal cord evokes a sustained increase in the adrenal section of catecholamines in the cat. JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1989; 27:181-92. [PMID: 2477435 DOI: 10.1016/0165-1838(89)90112-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The importance of cervical spinal pathways on the adrenal secretion of catecholamines was assessed in chloralose-anesthetized cats. Partial transections of the upper cervical spinal cord were made ipsilateral (n = 21) or contralateral (n = 10) to the adrenal vein sampling catheter. Ipsilateral cuts evoked an immediate increase in the adrenal secretion of epinephrine that remained elevated at 60 min (+89.7 +/- 27.0 ng/min, P less than 0.001) and increased the epinephrine/norepinephrine secretory ratio from 1.99 +/- 0.4 to 5.02 +/- 0.6 by 60 min (P less than 0.01) indicating a preferential augmentation of the secretion of epinephrine. The magnitude of the increase in secretion of epinephrine was well correlated with the cross-sectional area of the ipsilateral cut (rs = 0.681, P less than 0.01). In contrast, partial transections of similar size made contralateral to the adrenal vein sample evoked significantly smaller increases in the adrenal secretion of epinephrine by 60 min (+12.7 +/- 4.8 ng/min) and were not correlated with the cross-sectional area of the cut. The region of transection common to those experiments that caused the greatest increase in the secretion of catecholamines included the deep laminae (laminae V-VII) within the central gray matter as well as a portion of the dorsal columns. Transections restricted to the dorsolateral and lateral funiculi caused small and inconsistent changes in the adrenal secretion of catecholamines. Ipsilateral and contralateral cuts evoked similar effects on peripheral concentrations of catecholamines, on plasma adrenocorticotropin and on plasma angiotensin II, suggesting that the facilitatory effect of ipsilateral cuts on the adrenal secretion of catecholamines was not the result of a humoral mechanism. Arterial pressure and heart rate increased equally by 1 min and returned to prestimulus values by 5 min after transections of the ipsilateral or of the contralateral cervical cord. Electrical stimulation of the ipsilateral cervical spinal cord, caudal to the level of transection, decreased the secretion of epinephrine and arterial pressure by 1 min (-30.5 +/- 9.0%. P less than 0.05) suggesting the presence of an active inhibitory mechanism that persisted after transection. The results indicated that transections of pathways ipsilateral, but not contralateral, to the adrenal medulla that traverse the upper cervical spinal cord evoke a persistent increase in the adrenal secretion of epinephrine, whereas other indices of neuroendocrine or autonomic function do not reflect this tonic influence.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- D A Bereiter
- Section of Neurobiology, Brown University/Rhode Island Hospital, Providence 02903
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