Intact Cord Research Articles

Nicotinic acetylcholine receptor (nAChR) mediated dopamine release in larval Drosophila melanogaster

Acetylcholine is an excitatory neurotransmitter in the central nervous system of insects and the nicotinic acetylcholine receptor (nAChR) is a target for neonicotinoid insecticides. Functional insect nAChRs are difficult to express in host cells, and hence difficult to study. In mammals, acetylcholine and nicotine evoke dopamine release, but the extent to which this mechanism is conserved in insects is unknown. In intact larval ventral nerve cords (VNCs), we studied dopamine evoked by acetylcholine, nicotine, or neonicotinoids. Using fast-scan cyclic voltammetry, we confirmed dopamine was measured by its cyclic voltammogram and also by feeding Drosophila the synthesis inhibitor, 3-iodotyrosine, which lowered the evoked dopamine response. Acetylcholine (1.8 pmol) evoked on average 0.43 ± 0.04 μM dopamine. Dopamine release significantly decreased after incubation with α-bungarotoxin, demonstrating the release is mediated by nAChR, but atropine, a muscarinic AChR antagonist, had no effect. Nicotine (t1/2 = 71 s) and the neonicotinoids nitenpyram and imidacloprid (t1/2 = 86 s, 121 s respectively) also evoked dopamine release, which lasted longer than acetylcholine-stimulated release (t1/2 = 19 s). Nicotine-stimulated dopamine was significantly lower in the presence of sodium channel blocker, tetrodotoxin, showing that the release is exocytotic. Drosophila that have mutations in the nAChR subunit α1 or β2 have significantly lower neonicotinoid-stimulated release but no changes in nicotine-stimulated release. This work demonstrates that nAChR agonists mediate dopamine release in Drosophila larval VNC and that mutations in nAChR subunits affect how insecticides stimulate dopamine release.

Whole blood volumes associated with milking intact and cut umbilical cords in term newborns

The objective of this study is to determine placental transfusion blood volumes with intact and cut umbilical cord milking in term newborns. Sixty women at ≥37 weeks' gestation were enrolled. Following delivery, the umbilical cord was immediately clamped and cut to separate the newborn. Either intact umbilical cord milking (I-UCM) of the placental-umbilical cord unit or cut umbilical cord milking (C-UCM) of the cut umbilical cord segment was performed. For I-UCM, the cord underwent milking three or four times while being attached to placental circulation. For C-UCM, a 10, 20, or 30 cm cord segment was cut separately and milked four times. Blood volumes were compared between I-UCM and C-UCM methods. Mean blood volume with I-UCM (×4) was increased compared to the 30 cm C-UCM technique (48.5 ± 19.0 vs. 24.8 ± 4.0 mL, P < 0.001). For C-UCM, blood volume increased proportionally to cord length and, by the second milking, 98.1 ± 4.5% of blood volume was delivered. I-UCM provides a greater blood volume than C-UCM. With C-UCM, milking the cord more than twice offers no additional advantage.

Elimination of Left-Right Reciprocal Coupling in the Adult Lamprey Spinal Cord Abolishes the Generation of Locomotor Activity.

The contribution of left-right reciprocal coupling between spinal locomotor networks to the generation of locomotor activity was tested in adult lampreys. Muscle recordings were made from normal animals as well as from experimental animals with rostral midline (ML) spinal lesions (~13%→35% body length, BL), before and after spinal transections (T) at 35% BL. Importantly, in the present study actual locomotor movements and muscle burst activity, as well as other motor activity, were initiated in whole animals by descending brain-spinal pathways in response to sensory stimulation of the anterior head. For experimental animals with ML spinal lesions, sensory stimulation could elicit well-coordinated locomotor muscle burst activity, but with some significant differences in the parameters of locomotor activity compared to those for normal animals. Computer models representing normal animals or experimental animals with ML spinal lesions could mimic many of the differences in locomotor activity. For experimental animals with ML and T spinal lesions, right and left rostral hemi-spinal cords, disconnected from intact caudal cord, usually produced tonic or unpatterned muscle activity. Hemi-spinal cords sometimes generated spontaneous or sensory-evoked relatively high frequency “burstlet” activity that probably is analogous to the previously described in vitro “fast rhythm”, which is thought to represent lamprey locomotor activity. However, “burstlet” activity in the present study had parameters and features that were very different than those for lamprey locomotor activity: average frequencies were ~25 Hz, but individual frequencies could be >50 Hz; burst proportions (BPs) often varied with cycled time; “burstlet” activity usually was not accompanied by a rostrocaudal phase lag; and following ML spinal lesions alone, “burstlet” activity could occur in the presence or absence of swimming burst activity, suggesting the two were generated by different mechanisms. In summary, for adult lampreys, left and right hemi-spinal cords did not generate rhythmic locomotor activity in response to descending inputs from the brain, suggesting that left-right reciprocal coupling of spinal locomotor networks contributes to both phase control and rhythmogenesis. In addition, the present study indicates that extreme caution should be exercised when testing the operation of spinal locomotor networks using artificial activation of isolated or reduced nervous system preparations.

Feasibility and safety of intact cord resuscitation in newborn infants with congenital diaphragmatic hernia (CDH)

BackgroundStarting resuscitation before clamping the umbilical cord at birth may progressively increase pulmonary blood flow while umbilical venous blood flow is still contributing to maintenance of oxygenation and left ventricle preload. ObjectiveTo evaluate the feasibility, safety, and effects of intact cord resuscitation (ICR) on cardiorespiratory adaptation at birth in newborn infants with CDH. Study designProspective, observational, single-center pilot study. MethodsPhysiologic variables and outcomes were collected prospectively in 40 consecutive newborn infants with an antenatal diagnosis of isolated CDH. ResultsInfants were managed with immediate cord clamping (ICC group) from 1/2012 to 5/2014 or the cord was clamped after initiation of resuscitation maneuvers (ICR group) from 6/2014 to 4/2016 (20 in each group). Ante- and postnatal markers of CDH severity were similar between groups. Resuscitation before cord clamping was possible for all infants in the ICR group. No increase in maternal or neonatal adverse events was observed during the period of ICR. The pH was higher and the plasma lactate concentration was significantly lower at one hour after birth in the ICR than in the ICC group (pH=7.17±0.1 vs 7.08±0.2; lactate=3.6±2.3 vs 6.6±4.3mmol/l, p<0.05). Mean blood pressure was significantly higher in the ICR than in the ICC group at H1 (52±7.7 vs 42±7.5mmHg), H6 (47±3.9 vs 40±5.6mmHg) and H12 (44±2.9 vs 39±3.3mmHg) (p<0.05). ConclusionCommencing resuscitation and initiating ventilation while the infant is still attached to the placenta is feasible in infants with CDH. The procedure may support the cardiorespiratory transition at birth in infants with CDH.

Umbilical Cord Milking in Term Infants: Blood Volume Associated With Cut and Intact Umbilical Cords [23M

INTRODUCTION: Placental-to-newborn transfusion through delayed cord clamping and umbilical cord milking (UCM) is associated with reduced risk of transfusion, intraventricular hemorrhage, and necrotizing enterocolitis in preterm infants, and increased iron stores in term infants. Total blood volume (BV) transferred during UCM is not well studied. We sought to determine BV associated with both cut UCM (C-UCM) and intact UCM (I-UCM) methods in term infants. METHODS: Forty-five term infants were enrolled at a single center. To determine BV with C-UCM, umbilical cords from 30 infants (10 per group) were cut at 10, 20, or 30 centimeters, milked 4 times, and BV recorded. To determine BV with I-UCM, intact umbilical cords of 15 infants were milked 3 times and BV recorded. Demographic data and pregnancy data were obtained. Descriptive statistics were performed. RESULTS: In the C-UCM group, BV increased proportional to umbilical cord length, whereas BV/cm of cord decreased with cord length. C-UCM of a 30 cm segment contained a mean BV of 24.8±4.0 mL, or 8.0±1.3 mL/kg of birth weight. Most of the BV was obtained with the first milking (90.1±11.0%). In the I-UCM group, the mean BV was 46.3±24.1 mL, or 13.4±7.1 mL/kg of birth weight. No correlation existed between birth weight, placental weight, or BV. CONCLUSION: When performing C-UCM, cutting a long cord segment and milking 1 to 2 times delivers the highest BV. Compared to C-UCM, I-UCM provided greater average BV to newborn term infants. Future research should compare the clinical outcomes of infants who undergo C-UCM and I-UCM.

Providing a Placental Transfusion in Newborns Who Need Resuscitation.

Over the past decade, there have been several studies and reviews on the importance of providing a placental transfusion to the newborn. Allowing a placental transfusion to occur by delaying the clamping of the umbilical cord is an extremely effective method of enhancing arterial oxygen content, increasing cardiac output, and improving oxygen delivery. However, premature and term newborns who require resuscitation have impaired transitional hemodynamics and may warrant different methods to actively provide a placental transfusion while still allowing for resuscitation. In this review, we will provide evidence for providing a placental transfusion in these circumstances and methods for implementation. Several factors including cord clamping time, uterine contractions, umbilical blood flow, respirations, and gravity play an important role in determining placental transfusion volumes. Finally, while many practitioners agree that a placental transfusion is beneficial, it is not always straightforward to implement and can be performed using different methods, making this basic procedure important to discuss. We will review three placental transfusion techniques: delayed cord clamping, intact umbilical cord milking, and cut-umbilical cord milking. We will also review resuscitation with an intact cord and the evidence in term and preterm newborns supporting this practice. We will discuss perceived risks versus benefits of these procedures. Finally, we will provide key straightforward concepts and implementation strategies to ensure that placental-to-newborn transfusion can become routine practice at any institution.

Open laryngectomy: Clinical experience

Introduction. The problem of treatment and rehabilitation of patients with laryngeal cancer has been a complicated and controversial one. Important conditions for selection of the type and scale of functionally sparing surgical intervention are accurate preoperative diagnosis of advancement of the tumor and oncological appropriateness of the intervention. Currently, the problem of single-step reconstruction of lost laryngeal functions after organ-preserving surgeries remains open. For this purpose, researchers use both auto-/homografts and endoprosthetics made of various materials. In some cases, endoprosthetics in lyrengectomy didn’t allow to restore laryngeal lumen due to granulation tissue, cicatricial stenosis, laryngotracheomalacia. The study objective is to increase treatment and rehabilitation effectiveness in patients with laryngeal cancer after open laryngectomy. Materials and methods. Our experience is based on open laryngectomies in 86 patients performed at the Clinical Oncology Dispensary No. 1 of the Moscow Healthcare Department in the period from 2011 to 2014. Primary laryngeal cancer was diagnosed in 84 (97.7 %) patients, recurrent laryngeal cancer after a full course of radiation therapy – in 2 (2.3 %) patients. Vertical laryngectomy was performed in 74 patients, horizontal – in 12 patients. Vertical laryngectomies were performed for tumors located near the vocal and vestibular flaps, anterior commissure, subglottis, laryngeal sinus; horizontal for tumors located near the epiglottis, vestibular flaps, vallecula, root of the tongue if arytenoids were intact and vocal cords were mobile. In the postoperative period, an important factor was restoration of the organ’s function through early rehabilitation of respiratory, vocal, and protective functions. Evaluation of the laryngeal lumen was performed using endoscopic examination. Any diagnosed ligatures, granulation tissue, scars were resected. Prior to decannulation, ultrasound examination of the larynx was performed. Effectiveness of vocal function restoration was evaluated using computer acoustic analysis of the voice. Results. Restoration of the lost laryngeal functions after organ-preserving open laryngectomies in patients with laryngeal cancer is achieved through reconstruction of the remaining parts of the organ, formation of an adequate lumen for breathing through postoperative endoscopic correction, and early rehabilitation of respiratory, vocal, and protective function. Conclusion. Open laryngectomies with restoration of the remaining parts and single-step reconstruction of the lumen with an endoprosthesis, as well as subsequent combined treatment, allowed to restore respiratory function in 93.1 % patients, vocal function – in 91.9 % patients.

Role of immediate recurrent laryngeal nerve reconstruction in surgery for thyroid cancers with fixed vocal cords.

Quality of voice after immediate recurrent laryngeal nerve (RLN) reconstruction in thyroid cancers has not been thoroughly studied. Thirteen patients with fixed vocal cords (fixed vocal cord group) and 8 patients with intact or impaired mobile vocal cords (mobile vocal cord group) who had immediate RLN reconstruction simultaneously with total thyroidectomy, and patients who had arytenoid adduction and thyroplasty for vocal cord paralysis caused by previous surgery (arytenoid adduction thyroplasty group) were enrolled in this study. Preoperative phonation efficiency index was significantly lower (p = .008) in the fixed vocal cord group than in the mobile vocal cord group. One year after surgery, all voice parameters of the patients in the fixed vocal cord group had improved, compared with their preoperative data. The fixed vocal cord group had attained satisfactory voice qualities equivalent to those of the mobile vocal cord group in terms of various voice parameters. The present results support the idea that immediate RLN reconstruction at the time of surgery for thyroid cancers may spare the need for subsequent arytenoid adduction thyroplasty even in the patients with preoperatively fixed vocal cords. © 2016 Wiley Periodicals, Inc. Head Neck 39: 427-431, 2017.

Temporal and Spatial Evolution of Raised Intraspinal Pressure after Traumatic Spinal Cord Injury.

Traumatic spinal cord injury (SCI) often leads to permanent neurological impairment. Currently, the only clinically effective intervention for patients with acute SCI is surgical decompression by removal of impinging bone fragments within 24 h after injury. Recent clinical studies suggest that elevated intraparenchymal spinal pressure (ISP) limits functional recovery following SCI. Here, we report on the temporal and spatial patterns of elevated ISP following a moderate rodent contusion SCI. Compared with physiological ISP in the intact cord (2.7 ± 0.5 mm Hg), pressures increase threefold 30 min following injury (8.9 ± 1.1 mm Hg, p < 0.001) and remain elevated for up to 7 days (4.3 ± 0.8 mm Hg). Measurements of rostrocaudal ISP distribution reveal peak pressures in the injury center and in segments rostral to the injury during the acute phase(≤ 24 h). During the subacute phase(≥ 72 h), peak ISP decreases while a 7.5 mm long segment of moderately elevated ISP remains, centered on the initial contusion site. Interestingly, the contribution of the dural and pial compartments toward increased ISP changes with time after injury: Dural and pial linings contribute almost equally to increased ISP during the acute phase, whereas the dural lining is primarily responsible for elevated ISP during the subacute phase (78.9%). Our findings suggest that a rat contusion SCI model in combination with novel micro-catheters allows for direct measurement of ISP after SCI. Similarly to traumatic brain injury, raised tissue pressure is likely to have detrimental effects on spontaneous recovery following SCI.

Neonatal Resuscitation with an Intact Cord: A Randomized Clinical Trial

To assess whether providing ventilation during delayed cord clamping (V-DCC) increases placental transfusion compared with delayed cord clamping alone (DCC only). Inborn premature infants (230/7-316/7 weeks' gestational age) were randomized to receive at least 60 seconds of V-DCC (initial continuous positive airway pressure) with addition of positive pressure ventilation if needed) or without assisted ventilation (DCC only). For the DCC-only group, infants were dried and stimulated by gently rubbing the back if apneic. The primary outcome was the peak hematocrit in the first 24 hours of life. Delivery room outcomes were analyzed from video recordings and a data acquisition system. Hemodynamic measurements were performed with the use of functional echocardiography, near-infrared spectroscopy, and electrical cardiometry. There was no difference in the primary outcome of peak hematocrit in the first 24 hours of life. The onset of breathing was similar between both groups (25 ± 20 and 27 ± 28 seconds, P = .627); however, infants receiving DCC received a greater duration of stimulation than V-DCC (41 ± 19 and 20 ± 21 seconds P = .002). There were no differences in delivery room interventions, early hemodynamics (cerebral oxygenation by near-infrared spectroscopy, cardiac output and stroke volume by electrical cardiometry, or superior vena cava flow by of functional echocardiography), or neonatal outcomes. V-DCC was feasible but did not lead to any measurable clinical improvements immediately after delivery or reduce subsequent neonatal morbidity. Caretakers should consider providing adequate stimulation before cord clamping. ClinicalTrials.gov: NCT02231411.

Organization of flexor-extensor interactions in the mammalian spinal cord: insights from computational modelling.

Alternation of flexor and extensor activity in the mammalian spinal cord is mediated by two classes of genetically identified inhibitory interneurons, V1 and V2b. The V1 interneurons are essential for high-speed locomotor activity. They secure flexor-extensor alternations in the intact cord but lose this function after hemisection, suggesting that they are activated by inputs from the contralateral side of the cord. The V2b interneurons are involved in flexor-extensor alternations in both intact cord and hemicords. We used a computational model of the spinal network, simulating the left and right rhythm-generating circuits interacting via several commissural pathways, and extended this model by incorporating V1 and V2b neuron populations involved in flexor-extensor interactions on each cord side. The model reproduces multiple experimental data on selective silencing and activation of V1 and/or V2b neurons and proposes the organization of their connectivity providing flexor-extensor alternation in the spinal cord. Alternating flexor and extensor activity represents the fundamental property underlying many motor behaviours including locomotion. During locomotion this alternation appears to arise in rhythm-generating circuits and transpires at all levels of the spinal cord including motoneurons. Recent studies in vitro and in vivo have shown that flexor-extensor alternation during locomotion involves two classes of genetically identified, inhibitory interneurons: V1 and V2b. Particularly, in the isolated mouse spinal cord, abrogation of neurotransmission derived by both V1 and V2b interneurons resulted in flexor-extensor synchronization, whereas selective inactivation of only one of these neuron types did not abolish flexor-extensor alternation. After hemisection, inactivation of only V2b interneurons led to the flexor-extensor synchronization, while inactivation of V1 interneurons did not affect flexor-extensor alternation. Moreover, optogenetic activation of V2b interneurons suppressed extensor-related activity, while similar activation of V1 interneurons suppressed both flexor and extensor oscillations. Here, we address these issues using the previously published computational model of spinal circuitry simulating bilateral interactions between left and right rhythm-generating circuits. In the present study, we incorporate V1 and V2b neuron populations on both sides of the cord to make them critically involved in flexor-extensor interactions. The model reproduces multiple experimental data on the effects of hemisection and selective silencing or activation of V1 and V2b neurons and suggests connectivity profiles of these neurons and their specific roles in left-right (V1) and flexor-extensor (both V2b and V1) interactions in the spinal cord that can be tested experimentally.

Motherside care of the term neonate at birth.

The rationale for keeping the mother and her newborn together even when neonatal resuscitation is required is presented. The development of a customised mobile resuscitation trolley is detailed explaining how the resuscitation team can be provided with all the facilities of a standard resuscitation trolley to resuscitate the neonate at the mother’s side with an intact cord. Alternative low tech solutions which may be appropriate in low resource setting and with a low risk population are also described.

Bedside resuscitation of newborns with an intact umbilical cord: Experiences of midwives from British Columbia

Contextlevel 1 evidence supports the practice of delayed cord clamping, and many doctors and midwives consider it routine care when delivering vigorous, term neonates. However, scarce research exists regarding the risks or benefits of delayed cord clamping for infants needing resuscitation with positive pressure ventilation. Nonetheless, some midwives in British Columbia already practice intact cord resuscitation (ICR) at planned home births and in the hospital in order to facilitate delayed cord clamping for infants who need resuscitation. Methodswe distributed an online survey to all registered midwives in British Columbia through the Midwives Association of BC between October 22nd and November 13th, 2014. This survey examined how midwives balance a commitment to delayed cord clamping with the need for resuscitation in home and hospital settings. Findingsa total of 82 midwives responded to the survey (response rate=35%). Many have practiced ICR (56, 69%). However, the majority (42, 78%) of respondents had only performed this type of resuscitation at planned home births and not in the hospital setting. In both settings, midwives found the ergonomics of resuscitation with an intact cord challenging, but cited a smoother physiologic transition for neonates as their primary reasons for this practice, despite the obstacles. Midwives reported a greater ability to use their delivery equipment to provide stable thermoregulation at the bedside at planned home births during a resuscitation compared with the set up of hospital delivery rooms. Conclusionalthough the majority of participants practice ICR at planned home births, very few use this practice in the hospital setting. In the home, ergonomics is the primary obstacle for easily practicing ICR; hospital culture, protocols and lack of training are additional barriers to this practice in the hospital setting. Ergonomics and lack of appropriate set up in the delivery room were also primary obstacles. Midwives expressed a desire to find ways to incorporate ICR into the hospital setting.

Innovation in immediate neonatal care: development of the Bedside Assessment, Stabilisation and Initial Cardiorespiratory Support (BASICS) trolley

ObjectiveBabies receive oxygen through their umbilical cord while in the uterus and for a few minutes after birth. Currently, if the baby is not breathing well at birth, the cord...

Is it time to rethink cord management when resuscitation is needed?

A newborn who receives a placental transfusion at birth, either from cord milking or delayed cord clamping, obtains about 30% more blood volume than the newborn whose cord is cut immediately. Receiving an adequate blood volume from placental transfusion at birth may be protective for the distressed neonate as it prevents hypovolemia and can support optimal perfusion to all organs. New research shows that ventilating before clamping the umbilical cord can reduce large swings in cardiovascular function and help to stabilize the newborn. Hypovolemia, often associated with nuchal cord or shoulder dystocia, may lead to an inflammatory cascade and subsequent ischemic injury. A sudden unexpected neonatal asystole at birth may occur from severe hypovolemia. The restoration of blood volume is an important action to protect the hearts and brains of these neonates. Current protocols for resuscitation imply immediate cord clamping and the care of the newborn away from the mother's bedside. We suggest that an intrapartum care provider can achieve placental transfusion for the distressed neonate by milking the cord several times or resuscitating the neonate at the perineum with an intact cord. Milking the cord can be done quickly within the current Neonatal Resuscitation Program guidelines. Cord blood gases can be collected with delayed cord clamping. Bringing the resuscitation to the mother's bedside is a novel concept and supports an intact cord. Adopting a policy for resuscitation with an intact cord in a hospital setting will take concentrated effort and team work by obstetrics, pediatrics, midwifery, and nursing.

Providing newborn resuscitation at the mother’s bedside: assessing the safety, usability and acceptability of a mobile trolley

BackgroundDeferring cord clamping at very preterm births may be beneficial for babies. However, deferring cord clamping should not mean that newborn resuscitation is deferred. Providing initial care at birth at the mother’s bedside would allow parents to be present during resuscitation, and would potentially allow initial care to be given with the cord intact. The aim of this study was to evaluate the usability of a new mobile trolley for providing newborn resuscitation by describing the range of resuscitation procedures performed on a group of babies, to assess the acceptability to clinicians compared with standard equipment, based on a questionnaire survey, to assess safety from post resuscitation temperature measurements and serious adverse event reports and to assess whether the trolley allowed resuscitation with the umbilical cord intact by assessing the proportion of babies that could be placed on the trolley to allow resuscitation with the cord intact.MethodsThe trolley was used when the attendance of a clinician trained in newborn life support was required at a birth. Clinicians were asked to complete a questionnaire about their experience of using the trolley. Serious adverse events were reported.Results78 babies were managed on the trolley. Median (range) gestation was 34 weeks (24 to 41 weeks). Median (range) birth weight was2470 grams (520 to 4080 grams). The full range of resuscitation procedures has been successfully provided, although only one baby required emergency umbilical venous catheterisation. 77/78 babies had a post resuscitation temperature above 36°C. There were no adverse events. Most clinicians rated the trolley as ‘the same’, ‘better’ or ’much better’ than conventional resuscitation equipment. In most situations, the baby could be resuscitated with umbilical cord intact, although on 18 occasions the cord was too short to reach the trolley.ConclusionsImmediate stabilisation at birth and resuscitation can be performed successfully and safely at the bedside using this trolley. In most cases this could be achieved with an intact umbilical cord.

G106 Providing Neonatal resuscitation at the maternal bedside with an intact umbilical cord

AimsDeferring cord clamping at very preterm births may be beneficial for babies. However, deferring cord clamping should not mean that newborn resuscitation is deferred. Providing initial care at birth at...

Quantity and Distribution of Proliferating Cells in the Juvenile and Adult Primate Spinal Cord

Iultipotent progenitors exist in the adult mam- malian central nervous system, capable of producing both neurons and glia. Their proliferation in the spi- nal cord is limited. Generation of putative stem/pro- genitor cells has been reported in intact and injured spinal cord of rodents and in a limited number in monkeys with a spinal injury, but not in intact spi- nal cord in vivo. We recently reported de novo gener- ated cells in the intact spinal cord of macaque mon- keys. Here we extend these findings by showing data of intact juvenile and neonatal monkey spinal cord. We used bromodeoxyuridine (BrdU) to label the de novo generated cells in the experimental animals and stud- ied their quantity and distribution at different time- points after the BrdU infusion. As expected, we found a significant elevation of the BrdU-labeled cells at neo- natal stage. However, there was no difference between juvenile and adult stages. These results suggest that the survival of newly born cells in the intact primate spinal cord does not change after juvenile stage and this could be used to further study repair mechanisms in adult primate spinal cord.

Patch Clamp Recordings from Embryonic Zebrafish Mauthner Cells

Mauthner cells (M-cells) are large reticulospinal neurons located in the hindbrain of teleost fish. They are key neurons involved in a characteristic behavior known as the C-start or escape response that occurs when the organism perceives a threat. The M-cell has been extensively studied in adult goldfish where it has been shown to receive a wide range of excitatory, inhibitory and neuromodulatory signals1. We have been examining M-cell activity in embryonic zebrafish in order to study aspects of synaptic development in a vertebrate preparation. In the late 1990s Ali and colleagues developed a preparation for patch clamp recording from M-cells in zebrafish embryos, in which the CNS was largely intact2,3,4. The objective at that time was to record synaptic activity from hindbrain neurons, spinal cord neurons and trunk skeletal muscle while maintaining functional synaptic connections within an intact brain-spinal cord preparation. This preparation is still used in our laboratory today. To examine the mechanisms underlying developmental synaptic plasticity, we record excitatory (AMPA and NMDA-mediated)5,6 and inhibitory (GABA and glycine) synaptic currents from developing M-cells. Importantly, this unique preparation allows us to return to the same cell (M-cell) from preparation to preparation to carefully examine synaptic plasticity and neuro-development in an embryonic organism. The benefits provided by this preparation include 1) intact, functional synaptic connections onto the M-cell, 2) relatively inexpensive preparations, 3) a large supply of readily available embryos 4) the ability to return to the same cell type (i.e. M-cell) in every preparation, so that synaptic development at the level of an individual cell can be examined from fish to fish, and 5) imaging of whole preparations due to the transparent nature of the embryos.

Patch Clamp Recordings from Embryonic Zebrafish Mauthner Cells

Mauthner cells (M-cells) are large reticulospinal neurons located in the hindbrain of teleost fish. They are key neurons involved in a characteristic behavior known as the C-start or escape response that occurs when the organism perceives a threat. The M-cell has been extensively studied in adult goldfish where it has been shown to receive a wide range of excitatory, inhibitory and neuromodulatory signals1. We have been examining M-cell activity in embryonic zebrafish in order to study aspects of synaptic development in a vertebrate preparation. In the late 1990s Ali and colleagues developed a preparation for patch clamp recording from M-cells in zebrafish embryos, in which the CNS was largely intact2,3,4. The objective at that time was to record synaptic activity from hindbrain neurons, spinal cord neurons and trunk skeletal muscle while maintaining functional synaptic connections within an intact brain-spinal cord preparation. This preparation is still used in our laboratory today. To examine the mechanisms underlying developmental synaptic plasticity, we record excitatory (AMPA and NMDA-mediated)5,6 and inhibitory (GABA and glycine) synaptic currents from developing M-cells. Importantly, this unique preparation allows us to return to the same cell (M-cell) from preparation to preparation to carefully examine synaptic plasticity and neuro-development in an embryonic organism. The benefits provided by this preparation include 1) intact, functional synaptic connections onto the M-cell, 2) relatively inexpensive preparations, 3) a large supply of readily available embryos 4) the ability to return to the same cell type (i.e. M-cell) in every preparation, so that synaptic development at the level of an individual cell can be examined from fish to fish, and 5) imaging of whole preparations due to the transparent nature of the embryos.