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1.
Neurol Sci ; 2024 Apr 12.
Article En | MEDLINE | ID: mdl-38607534

INTRODUCTION: Cognitive symptoms are reported commonly throughout all phases of a migraine; however, there is a paucity of objective cognitive profiling. Previous studies have been limited by practice effect, and variable populations. METHODS: Participants completed 1 month of daily testing with a computerised cognitive battery involving a simple reaction (SRT), choice reaction (CRT) and a working memory test (WM). Results were correlated with their diary to identify interictal scores, and scores during each phase of a migraine, and non-migraine headache days. RESULTS: A total of 16 patients with episodic migraine participated. During the headache phase of a migraine, responses to SRT, CRT and WM tasks were significantly slower and less accurate than interictally. During the postdrome, WM task performance was slower and less accurate. Non-migraine headache days were not associated with significant change. CONCLUSION: The headache and postdromal phase of a migraine day was associated with objective evidence of cognitive dysfunction in patients with episodic migraine.

2.
J Neurol Neurosurg Psychiatry ; 95(4): 375-383, 2024 Mar 13.
Article En | MEDLINE | ID: mdl-37798095

Idiopathic intracranial hypertension (IIH) is a condition of significant morbidity and rising prevalence. It typically affects young people living with obesity, mostly women of reproductive age, and can present with headaches, visual abnormalities, tinnitus and cognitive dysfunction. Raised intracranial pressure without a secondary identified cause remains a key diagnostic feature of this condition, however, the underlying pathophysiological mechanisms that drive this increase are poorly understood. Previous theories have focused on cerebrospinal fluid (CSF) hypersecretion or impaired reabsorption, however, the recent characterisation of the glymphatic system in many other neurological conditions necessitates a re-evaluation of these hypotheses. Further, the impact of metabolic dysfunction and hormonal dysregulation in this population group must also be considered. Given the emerging evidence, it is likely that IIH is triggered by the interaction of multiple aetiological factors that ultimately results in the disruption of CSF dynamics. This review aims to provide a comprehensive update on the current theories regarding the pathogenesis of IIH.


Intracranial Hypertension , Pseudotumor Cerebri , Humans , Female , Adolescent , Male , Pseudotumor Cerebri/complications , Headache/etiology , Obesity/complications
3.
Cephalalgia ; 43(6): 3331024231180562, 2023 06.
Article En | MEDLINE | ID: mdl-37264889

BACKGROUND: Calcitonin gene-related peptide monoclonal antibodies (CGRP mAb) are an effective treatment of migraine however may have possible off-target effects. Pre-clinical studies implicate CGRP in several aspects of bone turnover and homeostasis. The clinical effect of CGRP mAb on bone turnover is not known, however. METHODS: Between June 2021 and July 2022, a multi-centre prospective cohort study was undertaken with eligible patients undergoing paired testing of the validated bone turnover markers procollagen type I N-terminal propeptide (P1NP) and serum C-terminal telopeptide of type I collagen (CTX) prior to and at least three months following administration of a CGRP mAb. RESULTS: A total of 45 patients with a mean age of 41.8 (SD 11.9) were included in the final analysis, all of whom received a ligand-targeting CGRP mAb. Administration of a CGRP mAb was associated with a statistically significant increase in P1NP from 44.5 microg/L to 51.5 microg/L (p = 0.004), but no significant change in CTX. CONCLUSION: In otherwise homeostatic conditions, short-term administration of a CGRP mAb is associated with increased P1NP, a bone formation marker but not with increased CTX, a bone resorption marker. Further study is required to validate these findings over longer time periods, in a larger cohort, and in pre-existing states of increased calcium stress and bone-turnover.


Calcitonin Gene-Related Peptide , Peptide Fragments , Humans , Adult , Calcitonin Gene-Related Peptide/pharmacology , Prospective Studies , Biomarkers , Peptide Fragments/pharmacology , Bone Remodeling
4.
Cephalalgia ; 43(5): 3331024231168089, 2023 05.
Article En | MEDLINE | ID: mdl-37032616

OBJECTIVE: To perform a systematic review and meta-analysis of the epidemiology, precipitants, phenotype, comorbidities, pathophysiology, treatment, and prognosis of primary new daily persistent headache. METHODS: We searched PubMed/Medline, EMBASE, Cochrane, and clinicaltrials.gov until 31 December 2022. We included original research studies with any design with at least five participants with new daily persistent headache. We assessed risk of bias using National Institutes of Health Quality Assessment Tools. We used random-effects meta-analysis where suitable to calculate pooled estimates of proportions. The Preferred Reporting Items for Systematic Reviews and Meta-Analysis compliant study is registered with PROSPERO (registration number CRD42022383561). RESULTS: Forty-six studies met inclusion criteria, predominantly case series, including 2155 patients. In 67% (95% CI 57-77) of cases new daily persistent headache has a chronic migraine phenotype, however new daily persistent headache has been found to be less likely than chronic migraine to be associated with a family history of headache, have fewer associated migrainous symptoms, be less vulnerable to medication overuse, and respond less well to injectable and neuromodulatory treatments. CONCLUSIONS: New daily persistent headache is a well described, recognisable disorder, which requires further research into its pathophysiology and treatment. There is a lack of high-quality evidence and, until this exists, we recommend continuing to consider new daily persistent headache a distinct disorder.


Headache Disorders , Migraine Disorders , Humans , Headache Disorders/epidemiology , Headache Disorders/therapy , Headache Disorders/diagnosis , Headache , Migraine Disorders/diagnosis , Prognosis
5.
J Headache Pain ; 24(1): 36, 2023 Apr 04.
Article En | MEDLINE | ID: mdl-37016284

BACKGROUND: The role of inflammation and cytokines in the pathophysiology of primary headache disorders is uncertain. We performed a systematic review and meta-analysis to synthesise the results of studies comparing peripheral blood cytokine levels between patients with migraine, tension-type headache, cluster headache, or new daily persistent headache (NDPH), and healthy controls; and in migraine between the ictal and interictal stages. METHODS: We searched PubMed/Medline and Embase from inception until July 2022. We included original research studies which measured unstimulated levels of any cytokines in peripheral blood using enzyme-linked immunosorbent assay or similar assay. We assessed risk of bias using the Newcastle-Ottawa Quality Assessment Scale. We used random effects meta-analysis with inverse variance weighted average to calculate standardised mean difference (SMD), 95% confidence intervals, and heterogeneity for each comparison. This study is registered with PROSPERO (registration number CRD42023393363). No funding was received for this study. RESULTS: Thirty-eight studies, including 1335 patients with migraine (32 studies), 302 with tension-type headache (nine studies), 42 with cluster headache (two studies), and 1225 healthy controls met inclusion criteria. Meta-analysis showed significantly higher interleukin (IL)-6 (SMD 1.07, 95% CI 0.40-1.73, p = 0.002), tumour necrosis factor (TNF)-α (SMD 0.61, 95% CI 0.14-1.09, p = 0.01), and IL-8 (SMD 1.56, 95% CI 0.03-3.09, p = 0.04), in patients with migraine compared to healthy controls, and significantly higher interleukin-1ß (IL-1ß) (SMD 0.34, 95% CI 0.06-0.62, p = 0.02) during the ictal phase of migraine compared to the interictal phase. Transforming growth factor (TGF)-ß (SMD 0.52, 95% CI 0.18-0.86, p = 0.003) and TNF-α (SMD 0.64, 95% CI 0.33-0.96, p = 0.0001) were both higher in patients with tension-type headache than controls. CONCLUSIONS: The higher levels of the proinflammatory cytokines IL-6, IL-8 and TNF-α in migraine compared to controls, and IL-1ß during the ictal stage, suggest a role for inflammation in the pathophysiology of migraine, however prospective studies are required to confirm causality and investigate the mechanisms for the increase in cytokine levels identified. Cytokines may also have a role in tension-type headache. Due a lack of data, no conclusions can be made regarding cluster headache or NDPH.


Cluster Headache , Migraine Disorders , Tension-Type Headache , Humans , Cytokines , Tumor Necrosis Factor-alpha , Interleukin-8 , Inflammation
6.
Front Neurol ; 13: 1036798, 2022.
Article En | MEDLINE | ID: mdl-36408496

Objective: To assess the prevalence and burden of autonomic symptoms in migraine, and determine the relationship with migraine frequency. Background: Autonomic symptoms in migraine have been theorized to occur in the setting of inter-ictal sympathetic hypoactivity and hyper-sensitivity. There is limited data prospectively assessing cranial and extra-cranial autonomic symptoms with a validated instrument, or longitudinal data on the relationship between migraine disease activity and autonomic symptoms. Methods: Patients attending a single tertiary academic center were recruited into a prospective cohort study between September 2020 and June 2022. In addition to standard clinical care, they completed several surveys including the Composite Autonomic Symptom Scale (COMPASS-31) questionnaire, a validated survey of autonomic symptoms. Results: A total of 43 patients (66.7% female, median age 42, IQR 17) were included in the final analysis. There was a baseline 20 monthly headache days (MHD) (IQR 21.7), and 65.1% of the population had chronic migraine by ICHD-3 criteria. A significantly elevated weighted COMPASS-31 score was reported in 60.5% of respondents (mean 30.3, SD 13.3) at baseline. After 12 months treatment, significant improvements were reported in migraine frequency (median MHD 20-8.7) and disability (median Migraine Disability Assessment Score 67-48), but not in autonomic symptoms (mean score 30.3, SD 11.2). Conclusion: Autonomic symptoms were frequently reported in patients with migraine. However, they did not correlate with headache frequency or reversion to episodic frequency. Further study is required to elucidate specific approaches and treatments for autonomic symptoms, and further evaluate the underlying pathophysiological mechanisms.

7.
Aust Prescr ; 45(3): 88-92, 2022 Jun.
Article En | MEDLINE | ID: mdl-35755987

Patients with a suspected change in intracranial pressure or a trigeminal autonomic cephalgia require MRI. The need for investigation for other headache disorders is guided by the clinical evaluation of the patient. Particular care should be taken to identify any 'red flags'. Incidental findings on MRI occur in approximately 2% of patients. Patients with migraine have an increased rate of white matter lesions, but these are of uncertain clinical significance.

8.
Cephalalgia ; 42(11-12): 1274-1287, 2022 10.
Article En | MEDLINE | ID: mdl-35469447

BACKGROUND: Headache is a common presentation of postural tachycardia syndrome, yet robust prevalence data is lacking. OBJECTIVES: To undertake a systematic review and meta-analysis to estimate the prevalence of headache disorders in postural tachycardia syndrome, and to explore the potential shared pathophysiological mechanisms that underpin these conditions as well as treatment options. METHODS: Three databases were searched for publications evaluating prevalence of migraine (primary outcome) and general and orthostatic headache (secondary outcomes) in patients with postural tachycardia syndrome. Two independent reviewers selected studies and extracted data. A random-effects meta-analysis calculated the pooled prevalence of migraine in postural tachycardia syndrome. A narrative literature review explored the pathophysiology and treatment options for concurrent headache disorders and postural tachycardia syndrome. RESULTS: Twenty-three articles met inclusion criteria. Estimated pooled prevalence of migraine in postural tachycardia syndrome was 36.8% (95% CI 2.9-70.7%). Various shared pathophysiological pathways for these conditions, as well as proposed treatment strategies, were identified.Limitations: Heterogeneity of study design, populations, and methodology for identifying headache disorders and postural tachycardia syndrome limited the generalisability of results. CONCLUSIONS: Migraine is a commonly reported comorbidity in POTS, however the true prevalence cannot be determined from the current literature. Further studies are required to assess this comorbidity and investigate the underlying mechanisms, as well as identify effective treatment strategies.


Migraine Disorders , Postural Orthostatic Tachycardia Syndrome , Comorbidity , Headache/complications , Headache/epidemiology , Humans , Migraine Disorders/complications , Migraine Disorders/epidemiology , Postural Orthostatic Tachycardia Syndrome/epidemiology , Prevalence
9.
BMJ Open ; 12(3): e059647, 2022 03 08.
Article En | MEDLINE | ID: mdl-35260463

INTRODUCTION: Status migrainosus is a disabling complication of migraine, which frequently results in hospitalisation. For patients who fail to respond to simple analgesia, triptans and intravenous prochlorperazine or chlorpromazine, there are limited treatment options, and a paucity of high-quality evidence to guide clinical practice. Eptinezumab, an intravenous monoclonal antibody specific for the calcitonin gene-related peptide ligand which achieves maximal plasma concentration immediately following administration and may improve migraines from day one. Intravenous lignocaine is an anaesthetic medication used in treatment of status migrainosus, often requiring prolonged admissions and with potential cardiac adverse events. The aim of this study is to assess the efficacy and safety of eptinezumab in the treatment of status migrainosus in comparison to intravenous lidocaine. METHODS AND ANALYSIS: Status migrainosus inpatient treatment with eptinezumab is a randomised, controlled, single-centre clinical trial conducted in a parallel design with an active comparator conducted in Melbourne, Australia. This study randomises forty patients (1:1) to receive either eptinezumab or an infusion of intravenous lignocaine for up to 5 days. It will assess the effect of eptinezumab compared with intravenous lignocaine in aborting status migrainosus, with the primary outcome of time from infusion until resolution of pain. It will explore several secondary measures including change in health resource utilisation, effect on patient reported outcomes of migraine disability and the safety and tolerability of each medication. ETHICS AND DISSEMINATION: This study has been reviewed and approved by the Human Research Ethics Committee of Alfred Health, local reference number 443/21, and all participants will provide informed consent for participation in the trial and dissemination of results. TRIAL REGISTRATION NUMBER: The trial registration number is ACTRN12621001616864. The results of this study will be disseminated through peer-reviewed journals, conference presentations and social media.


Inpatients , Migraine Disorders , Antibodies, Monoclonal, Humanized , Double-Blind Method , Hospitalization , Humans , Lidocaine/therapeutic use , Migraine Disorders/drug therapy , Randomized Controlled Trials as Topic , Treatment Outcome
10.
Aust Prescr ; 45(1): 15-20, 2022 Feb.
Article En | MEDLINE | ID: mdl-35233134

Cluster headache is characterised by attacks of very severe, unilateral headache lasting 15-180 minutes, up to eight times per day. The attacks are associated with cranial autonomic symptoms on the same side and a sense of agitation or restlessness First-line acute abortive treatments include intranasal or subcutaneous sumatriptan or high-flow oxygen. Neuromodulation may benefit some patients First-line preventive therapy is high-dose verapamil. Close monitoring is required for the adverse effect of arrhythmia There are several emerging therapies that have either proven efficacy, or possible benefit for cluster headache. They include drugs aimed at the calcitonin gene-related peptide.

11.
Aust J Gen Pract ; 50(12): 915-921, 2021 12.
Article En | MEDLINE | ID: mdl-34845471

BACKGROUND: Migraine is a common neurological disorder, affecting one in seven people, and is the second leading cause of disability worldwide. OBJECTIVE: The aim of this article is to summarise the diagnosis, pathophysiology and treatment of migraine. DISCUSSION: Key to limiting the disability of migraine and progression to chronic migraine is addressing modifiable risk factors, including implementing effective preventive treatment and avoiding overuse of acute treatment. In this article, the authors review strategies for effective acute and preventive treatment of migraine and introduce the new treatments of migraine targeting calcitonin gene-related peptide signalling.


Migraine Disorders , Calcitonin Gene-Related Peptide , Humans , Migraine Disorders/diagnosis , Migraine Disorders/drug therapy , Risk Factors , Treatment Outcome
12.
Front Neurol ; 12: 746099, 2021.
Article En | MEDLINE | ID: mdl-34721272

The diagnosis of fat embolism syndrome typically involves neurological, respiratory and dermatological manifestations of microvascular occlusion 24-72 h after a precipitating event. However, fat embolism causing cerebral large vessel occlusion strokes and their sequelae have rarely been reported in the literature. This case series reports three patients with fat emboli post operatively causing cerebral large vessel occlusions, as well as a review of the literature to identify differences in clinical presentations and outcomes in stroke secondary to fat emboli causing large vessel occlusions compared to those with fat embolism syndrome.

13.
J Headache Pain ; 22(1): 121, 2021 Oct 09.
Article En | MEDLINE | ID: mdl-34625019

BACKGROUND: Calcitonin gene-related peptide (CGRP) is expressed throughout the body and is a known mediator of migraine, exerting this biological effect through activation of trigeminovascular, meningeal and associated neuronal pathways located in close proximity to the central nervous system. Monoclonal antibodies (mAb) targeting the CGRP pathway are an effective new preventive treatment for migraine, with a generally favourable adverse event profile. Pre-clinical evidence supports an anti-inflammatory/immunoregulatory role for CGRP in other organ systems, and therefore inhibition of the normal action of this peptide may promote a pro-inflammatory response. CASES: We present a case series of eight patients with new or significantly worsened inflammatory pathology in close temporal association with the commencement of CGRP mAb therapy. CONCLUSION: This case series provides novel insights on the potential molecular mechanisms and side-effects of CGRP antagonism in migraine and supports clinical vigilance in patient care going forward.


Calcitonin Gene-Related Peptide , Migraine Disorders , Antibodies, Monoclonal/adverse effects , Calcitonin , Central Nervous System , Humans , Migraine Disorders/drug therapy
14.
J Clin Med ; 10(13)2021 Jun 29.
Article En | MEDLINE | ID: mdl-34209849

The efficacy of onabotulinumtoxinA (OnaB-A) as a preventative treatment for chronic migraine, emerging fortuitously from clinical observation is now supported by class one evidence and over two decades of real-world clinical data. There is still limited ability to predict a clinically meaningful response to OnaB-A for individual patients, however. This review summarises briefly the proposed mechanism of OnaB-A in chronic migraine, the literature of predictors of clinical response, and recent developments in the field.

15.
CNS Neurosci Ther ; 22(7): 568-76, 2016 07.
Article En | MEDLINE | ID: mdl-27297686

AIMS: Patients with Fabry disease (FD) characteristically develop peripheral neuropathy at an early age, with pain being a crucial symptom of underlying pathology. However, the diagnosis of pain is challenging due to the heterogeneous and nonspecific symptoms. Practical guidance on the diagnosis and management of pain in FD is needed. METHODS: In 2014, experts met to discuss recent advances on this topic and update clinical guidance. RESULTS: Emerging disease-specific tools, including FabryScan, Fabry-specific Pediatric Health and Pain Questionnaire, and Würzburg Fabry Pain Questionnaire, and more general tools like the Total Symptom Score can aid diagnosis, characterization, and monitoring of pain in patients with FD. These tools can be complemented by more objective and quantifiable sensory testing. In male and female patients of any age, pain related to FD can be an early indication to start disease-specific enzyme replacement therapy before potentially irreversible organ damage to the kidneys, heart, or brain occurs. CONCLUSION: To improve treatment outcomes, pain should be diagnosed early in unrecognized or newly identified FD patients. Treatment should include: (a) enzyme replacement therapy controlling the progression of underlying pathology; (b) adjunctive, symptomatic pain management with analgesics for chronic neuropathic and acute nociceptive, and inflammatory or mixed pain; and (c) lifestyle modifications.


Fabry Disease/complications , Pain Management/methods , Pain/diagnosis , Pain/etiology , Analgesics, Non-Narcotic/therapeutic use , Anti-Inflammatory Agents, Non-Steroidal/therapeutic use , Diagnosis, Differential , Enzyme Replacement Therapy , Fabry Disease/pathology , Fabry Disease/therapy , Female , Ganglia, Spinal/pathology , Humans , Life Style , Male , Pain Measurement , Surveys and Questionnaires
16.
Muscle Nerve ; 50(3): 366-71, 2014 Sep.
Article En | MEDLINE | ID: mdl-24395492

INTRODUCTION: Charcot-Marie-Tooth (CMT) disease type 1A is the most common form of CMT. The main clinical features are distal weakness, sensory loss, and skeletal deformities. Although pain is a frequent complaint, small fiber involvement in CMT1A has not been studied extensively. METHODS: We assessed pain and small fiber involvement in 49 CMT1A patients using a variety of pain scales, pain questionnaires, and thermal thresholds. RESULTS: Forty-three of 49 patients (88%) complained of pain. The pain was localized to the feet in 61% of patients. Only 18% of patients had neuropathic pain. Cold and warm detection thresholds were elevated in 53% and 12% of patients, respectively. CONCLUSIONS: Our findings confirm that CMT1A patients have significant pain, which is more likely to be multifactorial in origin and suggests that a proportion of patients have small fiber dysfunction affecting mainly thinly myelinated Aδ fibers.


Charcot-Marie-Tooth Disease/complications , Charcot-Marie-Tooth Disease/pathology , Nerve Fibers/pathology , Pain/etiology , Adult , Cohort Studies , Cold Temperature , Confidence Intervals , Female , Hot Temperature , Humans , Male , Middle Aged , Pain Measurement , Pain Threshold , Surveys and Questionnaires , Thermosensing/physiology , Young Adult
17.
J Peripher Nerv Syst ; 16(4): 295-303, 2011 Dec.
Article En | MEDLINE | ID: mdl-22176144

Schwann cell dedifferentiation following nerve injury is important to permit neural survival and axonal regrowth. Animal studies have shown that the transcription factor c-Jun is upregulated in Schwann cells of injured and pathological nerves where it acts as an important regulator of Schwann cell plasticity, promoting dedifferentiation and demyelination. This pilot immunohistochemical study investigates whether c-Jun is also upregulated in human neuropathies. We examined c-Jun expression in normal and diseased human nerves, as well as in dermal myelinated nerve fibres. Our findings show that although as predicted c-Jun is rarely expressed in normal nerves, it is expressed in Schwann cell nuclei of pathological nerves as predicted by animal studies. Pathological dermal myelinated nerve fibres also show clear nuclear c-Jun expression. Further studies of c-Jun expression will help clarify its role in human neuropathies.


Nerve Fibers, Myelinated/metabolism , Peripheral Nervous System Diseases/metabolism , Proto-Oncogene Proteins c-jun/biosynthesis , Schwann Cells/metabolism , Adult , Aged , Aged, 80 and over , Female , Humans , Immunohistochemistry , Infant , Male , Middle Aged , Nerve Fibers, Myelinated/pathology , Peripheral Nervous System Diseases/pathology , Pilot Projects , Proto-Oncogene Proteins c-jun/analysis , Skin/innervation , Skin/metabolism , Young Adult
18.
Expert Rev Clin Immunol ; 6(2): 231-45, 2010 Mar.
Article En | MEDLINE | ID: mdl-20402386

This review focuses on recent developments in the treatment of inflammatory neuropathies arising from immune dysregulation, rather than from infectious causes. The dysimmune inflammatory neuropathies are diseases of the peripheral nerves that have varying etiologies and may respond to immunomodulatory therapies. They are characterized by inflammatory changes in the nerve with associated destruction of myelin and axons. The underlying immune mechanisms are better understood in some of these conditions than others. Correct diagnosis and treatment is important to prevent clinical progression. Randomized controlled trials of some treatments in the more common inflammatory neuropathies have clarified their effectiveness; however, there are still groups of patients who are resistant to currently available treatments and for whom little effective treatment is available. Newer, targeted biologics and larger controlled trials of existing and novel therapies in these conditions offer promise of improved morbidity and mortality in this group of diseases.


Adrenal Cortex Hormones/therapeutic use , Autoimmune Diseases of the Nervous System/physiopathology , Autoimmune Diseases of the Nervous System/therapy , Immunoglobulins, Intravenous/therapeutic use , Immunotherapy , Autoimmune Diseases of the Nervous System/diagnosis , Autoimmune Diseases of the Nervous System/immunology , Cyclosporine/therapeutic use , Diagnosis, Differential , Gait Disorders, Neurologic , Humans , Immunosuppressive Agents/therapeutic use , Interferon Type I/therapeutic use , Paraproteinemias , Recombinant Proteins
19.
J Comp Neurol ; 495(1): 37-52, 2006 Mar 01.
Article En | MEDLINE | ID: mdl-16432898

The development of the primary sensory innervation of the superficial dorsal horn (SDH) was studied in postnatal opossums Monodelphis domestica by using DiI labelling of primary afferents and with GSA-IB(4) lectin binding and calcitonin gene-related peptide (CGRP) immunoreactivity to label primary afferent subpopulations. We also compared the timing of SDH innervation in the cervical and lumbar regions of the spinal cord. The first primary afferent projections to SDH emerge from the most lateral part of the dorsal root entry zone at postnatal day 5 and project around the lateral edge of the SDH toward lamina V. Innervation of the SDH occurs slowly over the second and third postnatal weeks, with the most dorsal aspect becoming populated by mediolaterally oriented varicose fibers before the rest of the dorsoventral thickness of the SDH becomes innervated by fine branching varicose fibers. Labelling with GSA-IB(4) lectin also labelled fibers at the lateral edge of the dorsal horn and SDH at P5, indicating that the GSA-IB(4) is expressed on SDH/lamina V primary afferents at the time when they are making their projections into the spinal cord. In contrast, CGRP-immunoreactive afferents were not evident until postnatal day 7, when a few short projections into the lateral dorsal horn were observed. These afferents then followed a pattern similar to the development of GSA-IB(4) projects but with a latency of several days. The adult pattern of labelling by GSA-IB(4) is achieved by about postnatal day 20, whereas the adult pattern of CGRP labelling was not seen until postnatal day 30. Electron microscopy revealed a few immature synapses in the region of the developing SDH at postnatal day 10, and processes considered to be precursors of glomerular synapses (and thus of primary afferent origin) were first seen at postnatal day 16 and adopted their definitive appearance between postnatal days 28 and 55. Although structural and functional development of forelimbs of neonatal Monodelphis is more advanced than the hindlimbs, we found little evidence of a significant delay in the invasion of the spinal cord by primary afferents in cervical and lumbar regions. These observations, together with the broadly similar maturational appearance of histological sections of rostral and caudal spinal cord, suggest that, unlike the limbs they innervate, the spinal regions do not exhibit a large rostrocaudal gradient in their maturation.


Afferent Pathways/growth & development , Monodelphis/growth & development , Neurons, Afferent/metabolism , Posterior Horn Cells/growth & development , Spinal Nerve Roots/growth & development , Afferent Pathways/ultrastructure , Animals , Calcitonin Gene-Related Peptide/metabolism , Carbocyanines , Cell Differentiation/physiology , Cervical Vertebrae , Extremities/growth & development , Extremities/innervation , Ganglia, Spinal/growth & development , Ganglia, Spinal/ultrastructure , Growth Cones/metabolism , Growth Cones/ultrastructure , Immunohistochemistry , Lumbar Vertebrae , Microscopy, Electron, Transmission , Monodelphis/anatomy & histology , Neurons, Afferent/ultrastructure , Plant Lectins , Posterior Horn Cells/metabolism , Posterior Horn Cells/ultrastructure , Presynaptic Terminals/metabolism , Presynaptic Terminals/ultrastructure , Spinal Nerve Roots/ultrastructure
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