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IBRO Reports Jun 2018Complete spinal transection in adult rats results in poor recovery of hind limb function and severe urinary bladder dysfunction. Neonatal rats with spinal cord...
Complete spinal transection in adult rats results in poor recovery of hind limb function and severe urinary bladder dysfunction. Neonatal rats with spinal cord transection, however, exhibit spontaneous and significant recovery of micturition control. A previous study in which biotinylated-dextran amine (BDA) was used as an anterograde tracer demonstrated that primary afferent fibers from the fifth lumbar dorsal root ganglion (DRG) project more strongly and make more terminals in the ventral horn after neonatal spinal cord transection at the mid-thoracic level. In the present study, we injected BDA into the sixth lumbar (L6) DRG of neonatally spinalized rats to label primary afferent fibers that include visceral afferents. The labeled fibers projected to the intermediolateral nucleus (IML) in the intermediate zone on ipsilateral side of the L6 spinal segment, whereas no projections to the IML were observed in sham-operated or intact rats. The BDA-labeled fibers of neonatally spinalized rats formed varicose terminals on parasympathetic preganglionic neurons in the IML. These findings suggest that some primary afferent projections from the L6 DRG to the IML appear after neonatal spinal cord transection, and these de novo projections might contribute to the recovery of autonomic function such as micturition following spinal cord injury in the neonatal stage.
PubMed: 30135945
DOI: 10.1016/j.ibror.2017.11.002 -
JACC. Clinical Electrophysiology Sep 2017This study sought to examine the efficacy of low-level vagus nerve stimulation (LLVNS) in suppressing post-operative atrial fibrillation (POAF) and inflammatory... (Randomized Controlled Trial)
Randomized Controlled Trial
OBJECTIVES
This study sought to examine the efficacy of low-level vagus nerve stimulation (LLVNS) in suppressing post-operative atrial fibrillation (POAF) and inflammatory cytokines in patients undergoing cardiac surgery.
BACKGROUND
POAF often complicates cardiac surgery.
METHODS
Patients undergoing cardiac surgery were randomized to active or sham LLVNS. In all patients, a bipolar wire was sutured to the vagus nerve pre-ganglionic fibers alongside the lateral aspect of the superior vena cava. High-frequency (20 Hz) stimulation, 50% below the threshold for slowing the heart rate, was delivered for 72 h in the LLVNS group. The development of POAF was monitored continuously during the entire hospital stay by use of telemetry. Blood was collected on arrival in the intensive care unit and at 24 and 72 h for measurement of inflammatory cytokines. Patients were followed up within 1 month after cardiac surgery.
RESULTS
A total of 54 patients were randomized to either active LLVNS (n = 26) or sham control (n = 28). The baseline characteristics of the patients were balanced in the 2 groups. POAF occurred in 3 patients (12%) in the LLVNS group and 10 patients (36%) in the control group (hazard ratio: 0.28; 95% confidence interval: 0.10 to 0.85; p = 0.027). None of the patients developed any complications as a result of wire placement. At 72 h, serum tumor necrosis factor-α and interleukin-6 levels were significantly lower in the LLVNS group than in the control group.
CONCLUSIONS
These data suggest that LLVNS suppresses POAF and attenuates inflammation in patients undergoing cardiac surgery. Further studies are warranted.
Topics: Adult; Aged; Atrial Fibrillation; Cytokines; Female; Humans; Inflammation; Interleukin-6; Male; Middle Aged; Postoperative Complications; Prospective Studies; Thoracic Surgery; Tumor Necrosis Factor-alpha; Vagus Nerve; Vagus Nerve Stimulation
PubMed: 29759717
DOI: 10.1016/j.jacep.2017.02.019 -
Frontiers in Physiology 2018Nitric oxide (NO) is a diffusible gas and has multifarious effects on both pre- and postsynaptic events. As a consequence of complex excitatory and inhibitory...
Nitric oxide (NO) is a diffusible gas and has multifarious effects on both pre- and postsynaptic events. As a consequence of complex excitatory and inhibitory integrations, NO effects on neuronal activities are heterogeneous. Using preparations of neonatal rats that retain the splanchnic sympathetic nerves and the thoracic spinal cord as an experimental model, we report here that either enhancement or attenuation of NO production in the neonatal rat spinal cords could increase, decrease, or not change the spontaneous firing behaviors recorded from splanchnic sympathetic single fibers. To elucidate the mathematical features of NO-mediated heterogeneous responses, the ratios of changes in firing were plotted against their original firing rates. In log-log plots, a linear data distribution demonstrated that NO-mediated heterogeneity in sympathetic firing responses was well described by a power function. Selective antagonists were applied to test if glycinergic, GABAergic, glutamatergic, and cholinergic neurotransmission in the spinal cord are involved in NO-mediated power-law firing modulations (plFM). NO-mediated plFM diminished in the presence of mecamylamine (an open-channel blocker of nicotinic cholinergic receptors), indicating that endogenous nicotinic receptor activities were essential for plFM. Applications of strychnine (a glycine receptor blocker), gabazine (a GABA receptor blocker), or kynurenate (a broad-spectrum ionotropic glutamate receptor blocker) also caused plFM. However, strychnine- or kynurenate-induced plFM was diminished by L-NAME (an NO synthase inhibitor) pretreatments, indicating that the involvements of glycine or ionotropic glutamate receptor activities in plFM were secondary to NO signaling. To recapitulate the arithmetic natures of the plFM, the plFM were simulated by firing changes in two components: a step increment and a fractional reduction of their basal firing activities. Ionotropic glutamate receptor activities were found to participate in plFM by both components. In contrast, GABA receptor activities are involved in the component of fractional reduction only. These findings suggest that NO orchestrates a repertoire of excitatory and inhibitory neurotransmissions, incurs a shunting effect on postsynaptic membrane properties, and thus, alters sympathetic firing in a manner of plFM. We propose that the plFM mediated by NO forms a basic scheme of differential controls for heterogeneous sympathetic regulation of visceral functions.
PubMed: 29559921
DOI: 10.3389/fphys.2018.00163 -
Science Advances Feb 2018The present study has revealed that the lungfish has both structural and functional features of its system for physiological control of heart rate, previously considered...
The present study has revealed that the lungfish has both structural and functional features of its system for physiological control of heart rate, previously considered solely mammalian, that together generate variability (HRV). Ultrastructural and electrophysiological investigation revealed that the nerves connecting the brain to the heart are myelinated, conferring rapid conduction velocities, comparable to mammalian fibers that generate instantaneous changes in heart rate at the onset of each air breath. These respiration-related changes in beat-to-beat cardiac intervals were detected by complex analysis of HRV and shown to maximize oxygen uptake per breath, a causal relationship never conclusively demonstrated in mammals. Cardiac vagal preganglionic neurons, responsible for controlling heart rate via the parasympathetic vagus nerve, were shown to have multiple locations, chiefly within the dorsal vagal motor nucleus that may enable interactive control of the circulatory and respiratory systems, similar to that described for tetrapods. The present illustration of an apparently highly evolved control system for HRV in a fish with a proven ancient lineage, based on paleontological, morphological, and recent genetic evidence, questions much of the anthropocentric thinking implied by some mammalian physiologists and encouraged by many psychobiologists. It is possible that some characteristics of mammalian respiratory sinus arrhythmia, for which functional roles have been sought, are evolutionary relics that had their physiological role defined in ancient representatives of the vertebrates with undivided circulatory systems.
Topics: Animals; Autonomic Fibers, Preganglionic; Autonomic Nervous System; Brain Stem; Fishes; Gases; Heart; Heart Rate; Hypoxia; Mammals; Neural Conduction; Respiration; Vagus Nerve
PubMed: 29507882
DOI: 10.1126/sciadv.aaq0800 -
Autonomic Neuroscience : Basic &... Mar 2018Immunohistochemistry is used widely to identify cholinergic neurons, but this approach has some limitations. To address these problems, investigators developed...
Immunohistochemistry is used widely to identify cholinergic neurons, but this approach has some limitations. To address these problems, investigators developed transgenic mice that express enhanced green fluorescent protein (GFP) directed by the promoter for choline acetyltransferase (ChAT), the acetylcholine synthetic enzyme. Although, it was reported that these mice express GFP in all cholinergic neurons and non-neuronal cholinergic cells, we could not detect GFP in cardiac cholinergic nerves in preliminary experiments. Our goals for this study were to confirm our initial observation and perform a qualitative screen of other representative autonomic structures for the presences of GFP in cholinergic innervation of effector tissues. We evaluated GFP fluorescence of intact, unfixed tissues and the cellular localization of GFP and vesicular acetylcholine transporter (VAChT), a specific cholinergic marker, in tissue sections and intestinal whole mounts. Our experiments identified two major tissues where cholinergic neurons and/or nerve fibers lacked GFP: 1) most cholinergic neurons of the intrinsic cardiac ganglia and all cholinergic nerve fibers in the heart and 2) most cholinergic nerve fibers innervating airway smooth muscle. Most cholinergic neurons in airway ganglia stained for GFP. Cholinergic systems in the bladder and intestines were fully delineated by GFP staining. GFP labeling of input to ganglia with long preganglionic projections (vagal) was sparse or weak, while that to ganglia with short preganglionic projections (spinal) was strong. Total absence of GFP might be due to splicing out of the GFP gene. Lack of GFP in nerve projections from GFP-positive cell bodies might reflect a transport deficiency.
Topics: Animals; Choline O-Acetyltransferase; Cholinergic Fibers; Cholinergic Neurons; Female; Ganglia, Sympathetic; Green Fluorescent Proteins; Male; Mice; Mice, Transgenic; Vesicular Acetylcholine Transport Proteins
PubMed: 29288022
DOI: 10.1016/j.autneu.2017.12.005 -
Biomedical Research (Tokyo, Japan) 2017Noradrenergic modulation has been frequently discussed in the context of neural activities that are related to pelvic organs. The sacral preganglionic nucleus (SPN) is a...
Noradrenergic modulation has been frequently discussed in the context of neural activities that are related to pelvic organs. The sacral preganglionic nucleus (SPN) is a spinal nucleus containing parasympathetic preganglionic neurons that send fibers to pelvic nerves. In spite of the abundant presence of noradrenergic fibers around the SPN, the effects of noradrenaline (NA) remain obscure. To explore this issue, NA (50 μM) was applied to parasympathetic preganglionic neurons in the SPN during whole-cell patch clamp recording. The SPN was labeled with the retrograde tracer, DiI. These neurons demonstrated two classes of firing patterns (delayed and regular) in terms of initiation of firing. Independent of these firing patterns, NA induced inward (56%) or outward (32%) currents in labeled SPN neurons. Phenylephrine, an α1 receptor agonist, induced an inward current, and clonidine, an α2 receptor agonist, induced an outward current, indicating the existence of both α1 and α2 adrenoreceptors in DiI-labeled SPN neurons. NA also modulated synaptic currents according to the firing patterns. In delayed firing neurons, NA inhibited both spontaneous excitatory post-synaptic currents (sEPSCs) and spontaneous inhibitory post-synaptic currents (sIPSCs). Hence, NA facilitated sEPSCs and sIPSCs in about a half of regular firing neurons. Bath application of phenylephrine facilitated sEPSCs and sIPSCs, and clonidine inhibited them. These results support the hypothesis of multiple effects of NA in the SPN, and may suggest functional differences among SPN neurons.
Topics: Animals; Neurons; Norepinephrine; Patch-Clamp Techniques; Rats; Spinal Cord; Sympathomimetics
PubMed: 29225214
DOI: 10.2220/biomedres.38.359 -
Frontiers in Cellular Neuroscience 2017Functional properties of lamina X neurons in the spinal cord remain unknown despite the established role of this area for somatosensory integration, visceral...
Functional properties of lamina X neurons in the spinal cord remain unknown despite the established role of this area for somatosensory integration, visceral nociception, autonomic regulation and motoneuron output modulation. Investigations of neuronal functioning in the lamina X have been hampered by technical challenges. Here we introduce an spinal cord preparation with both dorsal and ventral roots still attached for functional studies of the lamina X neurons and their connectivity using an oblique LED illumination for resolved visualization of lamina X neurons in a thick tissue. With the elaborated approach, we demonstrate electrophysiological characteristics of lamina X neurons by their membrane properties, firing pattern discharge and fiber innervation (either afferent or efferent). The tissue preparation has been also probed using Ca imaging with fluorescent Ca dyes (membrane-impermeable or -permeable) to demonstrate the depolarization-induced changes in intracellular calcium concentration in lamina X neurons. Finally, we performed visualization of subpopulations of lamina X neurons stained by retrograde labeling with aminostilbamidine dye to identify sympathetic preganglionic and projection neurons in the lamina X. Thus, the elaborated approach provides a reliable tool for investigation of functional properties and connectivity in specific neuronal subpopulations, boosting research of lamina X of the spinal cord.
PubMed: 29163053
DOI: 10.3389/fncel.2017.00342 -
Neural Regeneration Research Sep 2017Autonomic dysreflexia (AD) is a serious cardiovascular disorder in patients with spinal cord injury (SCI). The primary underlying cause of AD is loss of supraspinal... (Review)
Review
Autonomic dysreflexia (AD) is a serious cardiovascular disorder in patients with spinal cord injury (SCI). The primary underlying cause of AD is loss of supraspinal control over sympathetic preganglionic neurons (SPNs) caudal to the injury, which renders the SPNs hyper-responsive to stimulation. Central maladaptive plasticity, including C-fiber sprouting and propriospinal fiber proliferation exaggerates noxious afferent transmission to the SPNs, causing them to release massive sympathetic discharges that result in severe hypertensive episodes. In parallel, upregulated peripheral vascular sensitivity following SCI exacerbates the hypertensive response by augmenting gastric and pelvic vasoconstriction. Currently, the majority of clinically employed treatments for AD involve anti-hypertensive medications and Botox injections to the bladder. Although these approaches mitigate the severity of AD, they only yield transient effects and target the effector organs, rather than addressing the primary issue of central sympathetic dysregulation. As such, strategies that aim to restore supraspinal reinnervation of SPNs to improve cardiovascular sympathetic regulation are likely more effective for AD. Recent pre-clinical investigations show that cell transplantation therapy is efficacious in reestablishing spinal sympathetic connections and improving hemodynamic performance, which holds promise as a potential therapeutic approach.
PubMed: 29089975
DOI: 10.4103/1673-5374.215241 -
PloS One 2017In Mexico, although the majority of births are attended in hospitals, reports have emerged of obstetric violence, use of unsafe practices, and failure to employ... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
In Mexico, although the majority of births are attended in hospitals, reports have emerged of obstetric violence, use of unsafe practices, and failure to employ evidence-based practices (EBP). Recent attention has refocused global efforts towards provision of quality care that is both patient-centered and evidence-based. Scaling up of local interventions should rely on strong evidence of effectiveness.
OBJECTIVE
To perform a secondary analysis to evaluate the impact of a simulation and team-training program (PRONTO) on the performance of EBP in normal births.
METHODS
A pair-matched cluster randomized controlled trial of the intervention was designed to measure the impact of the program (PRONTO intervention) on a sample of 24 hospitals (12 hospitals received the PRONTO training and 12 served as controls) in the states of Chiapas, Guerrero, and Mexico. We estimated the impact of receiving the intervention on the probability of birth practices performance in a sample of 641 observed births of which 318 occurred in the treated hospitals and 323 occurred in control hospitals. Data was collected at 4 time points (baseline, 4th, 8th and 12th months after the training). Women were blinded to treatment allocation but observers and providers were not. Estimates were obtained by fitting difference-in-differences logistic regression models considering confounding variables. The trial is registered at clinicaltrials.gov: # NCT01477554.
RESULTS
Significant changes were found following the intervention. At 4 months post-intervention an increase of 20 percentage points (p.p.) for complete Active Management of Third Stage of Labor (AMTSL) (p = 0.044), and 16 p.p. increase for Skin-to-Skin Contact (p = 0.067); at 12 months a 25 p.p. increase of the 1st step of AMTSL (p = 0.026) and a 42 p.p. increase of Delayed Cord Clamping (p = 0.004); at 4 months a 30 (p = 0.001) and at 8 months a 22 (p = 0.010) p.p. decrease for Uterine Sweeping.
CONCLUSIONS
The intervention has an impact on adopting EBP at birth, contributing to an increased quality of care. Long lasting impacts on these practices are possible if there were to be a widespread adoption of the training techniques including simulation, team-training and facilitated discussions regarding routine care.
Topics: Autonomic Fibers, Preganglionic; Delivery, Obstetric; Emergency Medical Services; Evidence-Based Practice; Health Personnel; Hospitals; Humans; Intensive Care, Neonatal; Mexico; Patient Care Team; Quality Improvement
PubMed: 28319122
DOI: 10.1371/journal.pone.0172623 -
Innovations in Clinical Neuroscience 2016Surgical treatment is not suitable for laryngopharyngeal reflux that is refractory to proton pump inhibitors. We present a case of proton pump inhibitor-refractory...
Surgical treatment is not suitable for laryngopharyngeal reflux that is refractory to proton pump inhibitors. We present a case of proton pump inhibitor-refractory laryngopharyngeal reflux that was successfully treated with sympathetic nerve entrapment point injection. The patient had previously been diagnosed with laryngopharyngeal reflux and treated with proton pump inhibitors for six months without substantial improvement. After sympathetic nerve entrapment point injection treatment, her reflux symptom index improved from 15 points to 1 point, and this response was maintained for six months. Hyperexcitability of T5 and T6 sympathetic preganglionic fibers appears to be the main cause of laryngopharyngeal reflux. Sympathetic nerve entrapment point injection may represent an alternative to anti-reflux procedures.
PubMed: 28210524
DOI: No ID Found