scholarly journals Electrophysiological properties of maxillary trigeminal Aβ-afferent neurons of rats

2021 ◽  
Vol 17 ◽  
pp. 174480692110212
Author(s):  
Yuya Okutsu ◽  
Akihiro Yamada ◽  
Sotatsu Tonomura ◽  
Ryan J Vaden ◽  
Jianguo G Gu
Keyword(s):  
Type I ◽  
Type Ii ◽  
Afferent Neurons ◽  
Success Rates ◽  
Fast Kinetics ◽  
Electrophysiological Properties ◽  
Type Iiia ◽  
Type Iiib ◽  
Slow Kinetics ◽  
Conduction Velocities

Aβ-afferents in maxillary or V2 trigeminal ganglion (TG) neurons are somatosensory neurons that may be involved in both non-nociceptive and nociceptive functions in orofacial regions. However, electrophysiological properties of these V2 trigeminal Aβ-afferent neurons have not been well characterized so far. Here, we used rat ex vivo trigeminal nerve preparations and applied patch-clamp recordings to large-sized V2 TG neurons to characterize their electrophysiological properties. All the cells recorded had afferent conduction velocities in the range of Aβ-afferent conduction speeds. However, these V2 trigeminal Aβ-afferent neurons displayed different action potential (AP) properties. APs showed fast kinetics in some cells but slow kinetics with shoulders in repolarization phases in other cells. Based on the derivatives of voltages in AP repolarization with time (dV/dt), we classified V2 trigeminal Aβ-afferent neurons into four types: type I, type II, type IIIa and type IIIb. Type I V2 trigeminal Aβ-afferent neurons had the largest dV/dt of repolarization, the fastest AP conduction velocities, the shortest AP and afterhyperpolarization (AHP) durations, and the highest AP success rates. In contrast, type IIIb V2 trigeminal Aβ-afferent neurons had the smallest dV/dt of AP repolarization, the slowest AP conduction velocities, the longest AP and AHP durations, and the lowest AP success rates. The type IIIb cells also had significantly lower voltage-activated K+ currents. For type II and type IIIa V2 trigeminal Aβ-afferent neurons, AP parameters were in the range between those of type I and type IIIb V2 trigeminal Aβ-afferent neurons. Our electrophysiological classification of V2 trigeminal Aβ-afferent neurons may be useful in future to study their non-nociceptive and nociceptive functions in orofacial regions.

Glenoid Rim Lesions Associated with Recurrent Anterior Dislocation of the Shoulder

1998 ◽  
Vol 26 (1) ◽  
pp. 41-45 ◽  
Author(s):  
Louis U. Bigliani ◽  
Peter M. Newton ◽  
Scott P. Steinmann ◽  
Patrick M. Connor ◽  
Stephen J. McIlveen
Keyword(s):  
Anterior Dislocation ◽  
Type I ◽  
Type Ii ◽  
Recurrent Instability ◽  
Fracture Fragment ◽  
Type Iiia ◽  
Type Iiib ◽  
Anterior Glenoid ◽  
Bony Fragment ◽  
The One

Twenty-five shoulders with recurrent instability and associated anterior glenoid rim lesions were reviewed to 1) develop a classification system of the lesions, 2) evaluate radiographic techniques in detecting the lesions, and 3) analyze the outcome of surgery. Lesions were classified into three types: Type I, a displaced avulsion fracture with attached capsule; Type II, a medially displaced fragment malunited to the glenoid rim; and Type III, erosion of the glenoid rim with less than 25% (Type IIIA) or greater than 25% (Type IIIB) deficiency. Lesions were detected by plain radiographs (19 shoulders) or supplemental CT-arthrograms (12 shoulders) or both. In 16 Type I fractures, both the bony fragment and capsule were reattached to the glenoid rim. In five Type II and three Type IIIA lesions, only the capsule was repaired to the remaining glenoid rim. In the one Type IIIB lesion, a coracoid transfer was performed. At an average followup of 30 months, 22 shoulders (88%) had satisfactory results without recurrent instability, whereas three shoulders (12%) had postoperative redislocations. The majority of recurrent anterior dislocations with associated glenoid rim lesions can be treated by suturing the fracture fragment or capsule or both to the glenoid rim and addressing associated capsular laxity.

scholarly journals Type I-like behavior of the type II α7 nicotinic acetylcholine receptor positive allosteric modulator A-867744

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7542 ◽  
Author(s):  
Krisztina Pesti ◽  
Peter Lukacs ◽  
Arpad Mike
Keyword(s):  
Nicotinic Acetylcholine Receptors ◽  
Single Channel ◽  
High Temporal Resolution ◽  
Type I ◽  
Type Ii ◽  
Nicotinic Acetylcholine ◽  
Fast Kinetics ◽  
Temporal Precision ◽  
Α7 Nachr ◽  
Α7 Nachrs

Cognitive impairment often involves the decreased expression or hypofunction of alpha 7-type nicotinic acetylcholine receptors (α7 nAChRs). Agonists or positive allosteric modulators (PAMs) of α7 nAChRs are known to be potential treatments for dementias, different neurodegenerative disorders, pain syndromes and conditions involving inflammation. In some of these conditions, it is desirable to maintain the temporal precision of fast cholinergic events, while in others, this temporal precision is unnecessary. For this reason, the optimal therapeutic effect for distinct indications may require PAMs with different mechanisms of action. The two major mechanisms are called “type I”, which are compounds that augment α7 nAChR-mediated currents but maintain their characteristic fast kinetics; and “type II”, which are compounds that produce augmented and prolonged currents. In this study, we performed a kinetic analysis of two type II PAMs of the α7 nAChR: PNU-120596 and A-867744, using a fast perfusion method that allowed high temporal resolution. We characterized the type of modulation produced by the two compounds, the state-dependence of the modulatory action, and the interaction between the two compounds. We found fundamental differences between the modulation mechanisms by PNU-120596 and A-867744. Most importantly, during brief agonist pulses, A-867744 caused a strikingly type I-like modulation, while PNU-120596 caused a type II-like prolonged activation. Our results demonstrate that specific compounds, even though all labeled as type II PAMs, can behave in completely different ways, including their onset and offset kinetics, state preference, and single channel open time. Our results emphasize that subtle details of the mechanism of action may be significant in assessing the therapeutic applicability of α7 nAChR PAM compounds.

scholarly journals Evaluation of compound tibial fractures managed with an Ilizarov ring fixator

2020 ◽  
Vol 6 (4) ◽  
pp. 710
Author(s):  
Praveen Ravi ◽  
Muthumanickam Ramanujam ◽  
Jambu Nageswaran ◽  
Sundar Suriyakumar
Keyword(s):  
Open Fractures ◽  
Tibial Fractures ◽  
Long Bone ◽  
Type Ii ◽  
Ring Fixator ◽  
Type Iiia ◽  
Type Iiib ◽  
Ilizarov Ring Fixator ◽  
Ilizarov Fixator ◽  
The Ideal

<p class="abstract"><strong>Background:</strong> The tibia is the most commonly fractured long bone and because of its location and the tenuous soft tissue coverage, its more prone for open fractures tibia than any other long bone. The ideal management of such fractures still remains controversial. We have evaluated the healing of fractures and functional outcomes in patients with open tibial fractures treated with an Ilizarov ring fixator.</p><p class="abstract"><strong>Methods:</strong> 32 patients who had open fractures of the tibia (II, IIIA or IIIB) who were treated with an Ilizarov fixator were included in the study. The patients were followed up for a minimum period of 1 year after removal of the fixator. Functional and radiological results were analysed using association for the study of applications of methods of Ilizarov scoring.<strong></strong></p><p class="abstract"><strong>Results:</strong> There were 20 cases of type IIIB, 7 cases of type IIIA, 5 cases of type II fractures. Union was achieved in all patients. Mean time for union was 25.2 weeks, with faster union times in type II, type IIIA fractures. Six cases of type IIIB needed flap cover. Limb discrepancy was seen in 3 cases. 17 cases of pin tract infections were seen, most of which were grade 3 and were managed with antibiotics. Two cases had delayed union, of which one was treated with bone marrow aspirate injection and the other one with bone grafting. At one year, 21 (65.6%) had excellent results, six (18.7%) had good results, four (12.5%) had fair outcomes and one (3.2%) had a poor result.</p><p class="abstract"><strong>Conclusions:</strong> Despite the associated complications, Ilizarov fixator is the ideal treatment for compound tibial fractures.</p>

Physiology of Neuronal Subtypes in the Respiratory–Vocal Integration Nucleus Retroamigualis of the Male Zebra Finch

2005 ◽  
Vol 94 (4) ◽  
pp. 2379-2390 ◽  
Author(s):  
M. F. Kubke ◽  
Y. Yazaki-Sugiyama ◽  
R. Mooney ◽  
J. M. Wild
Keyword(s):  
Motor Neurons ◽  
Zebra Finch ◽  
Synaptic Input ◽  
Cell Types ◽  
Inhibitory Input ◽  
Type I ◽  
Type Ii ◽  
Intracellular Recordings ◽  
Electrophysiological Properties ◽  
Premotor Neurons

Learned vocalizations, such as bird song, require intricate coordination of vocal and respiratory muscles. Although the neural basis for this coordination remains poorly understood, it likely includes direct synaptic interactions between respiratory premotor neurons and vocal motor neurons. In birds, as in mammals, the medullary nucleus retroambigualis (RAm) receives synaptic input from higher level respiratory and vocal control centers and projects to a variety of targets. In birds, these include vocal motor neurons in the tracheosyringeal part of the hypoglossal motor nucleus (XIIts), other respiratory premotor neurons, and expiratory motor neurons in the spinal cord. Although various cell types in RAm are distinct in their anatomical projections, their electrophysiological properties remain unknown. Furthermore, although prior studies have shown that RAm provides both excitatory and inhibitory input onto XIIts motor neurons, the identity of the cells in RAm providing either of these inputs remains to be established. To characterize the different RAm neuron types electrophysiologically, we used intracellular recordings in a zebra finch brain stem slice preparation. Based on numerous differences in intrinsic electrophysiological properties and a principal components analysis, we identified two distinct RAm neuron types (types I and II). Antidromic stimulation methods and intracellular staining revealed that type II neurons, but not type I neurons, provide bilateral synaptic input to XIIts. Paired intracellular recordings in RAm and XIIts further indicated that type II neurons with a hyperpolarization-dependent bursting phenotype are a potential source of inhibitory input to XIIts motor neurons. These results indicate that electrically distinct cell types exist in RAm, affording physiological heterogeneity that may play an important role in respiratory–vocal signaling.

scholarly journals Incidence of Carotico-clinoid Foramen and Interclinoid Osseous Bridge in Dry Human Skulls in Sudan_ Neurosurgical Interest

2020 ◽  
Author(s):  
yasser seddeg ◽  
Kamalelden Elbadawi
Keyword(s):  
Cavernous Sinus ◽  
Internal Carotid ◽  
Cross Sectional Study ◽  
Type I ◽  
Type Ii ◽  
Success Rates ◽  
Anterior Clinoid Process ◽  
Cross Sectional ◽  
Type Iv ◽  
Human Skulls

Background: Anterior clinoid process is usually drilled in order to approach cavernous sinus and related structures in neurosurgical operations. The presence of carotico-clinoid foramen and interclinoid osseous bridge create difficulties while approaching anterior clinoid process and increases the risks of injury to the internal carotid artery and nearby structures. Aim: To observe incidence, anatomy of carotico-clinoid foramen and interclinoid osseous bridge in the Sudanese dry skulls. Methods: This was a cross sectional study, conducted in the departments of anatomy in different medical schools in Sudan between the period from June 2019 to January 2020. Total 30 dry adult human skulls were examined to observe incidence of carotico-clinoid foramen and of interclinoid osseous bridge. Result: The incidence of carotico-clinoid foramen was 13.3% (4 skulls out of 30). The foramen was bilaterally present in one skull (n=1/30, 3.3%) and unilateral in 3 skulls (n=3/30, 10%). Type I bridge is the carotico-clinoid foramen itself, the Type II interclinoid osseous bridge was found in one skull (n=1/30, 3.3%) , no Type III and Type IV bridges were observed in the present study. Conclusion: the presence of this foramen and interclinoid osseous bridge can complicate neurosurgical operations in cavernous sinus, sellar and para-sellar regions. Therefore, the detailed anatomical knowledge is very important to decrease complications and to increase success rates of neurosurgical operations in this area.

scholarly journals Characterization of transgenic mouse lines for labeling type I and type II afferent neurons in the cochlea

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Pankhuri Vyas ◽  
Jingjing Sherry Wu ◽  
Adrian Jimenez ◽  
Elisabeth Glowatzki ◽  
Paul Albert Fuchs
Keyword(s):  
Transgenic Mouse ◽  
Type I ◽  
Type Ii ◽  
Afferent Neurons ◽  
Mouse Lines

scholarly journals Atresia of the Colon: Etiological Aberrations, Clinical Observations, and Challenges in Management

2018 ◽  
Vol 7 (2) ◽  
pp. 22 ◽  
Author(s):  
Nitin Pant ◽  
Sudhir Singh ◽  
Jiledar Rawat ◽  
Shiv Narayan Kureel ◽  
Ashish Wakhlu
Keyword(s):  
Sigmoid Colon ◽  
Primary Anastomosis ◽  
Care Center ◽  
Hepatic Flexure ◽  
Type I ◽  
Type Ii ◽  
Ascending Colon ◽  
Health Care Center ◽  
Colonic Atresia ◽  
Type Iiia

Objective: The objective of this study is to review the clinicoradiological profile, scheme of management and the outcome in cases of colonic atresia (CA), and ascertain an optimal approach for the treatment of CA to minimize morbidity and mortality. Design and Setting: This was a retrospective observational study carried out at a tertiary health‑care center. Duration: Total of 6 years duration (January 2011–December 2016).Materials and Methods: A retrospective analysis of 10 patients of CA managed over a 6- year period. Data related to demographics, clinical presentation, associated anomalies, radiologic, intraoperative findings, postoperative stay, complications, and outcome were analyzed.Results: There were three cases of Type II atresia involving terminal ileum, cecum, and adjacent colon. Three cases had proximal ascending colon atresia (Type IIIa [n = 2]; Type I [n = 1]) Type I [n=1], and two cases of type IIIa atresia of the hepatic flexure. Two babies had atresia involving the sigmoid colon; one had Type II atresia, while we were unable to assign a type to the other within the prevailing classification. Seven babies were initially treated with a stoma either in the ileum (n = 3), hepatic flexure (n = 2), and sigmoid colon (n = 2), whereas three were treated with a primary anastomoses. Cases treated with a primary anastomoses had lesser morbidity and a better outcome than those with an ileal or ascending colon stoma.Conclusion: Contrary to the theory of an acute antenatal vascular accident, CA may rarely result from a gradual, sequential obliteration of mesenteric vasculature. Primary anastomosis should be contemplated in proximal CA wherever possible as stomal complications, especially high stoma output can result in considerable morbidity.

scholarly journals Comparative study on intramedullary nailing versus AO external fixation in the management of gustilo type II, IIIA, and IIIB tibial shaft fractures.

2020 ◽  
Vol 27 (06) ◽  
pp. 1199-1205
Author(s):  
Khawand Bukhsh Umrani ◽  
Zamir Hussain Tunio ◽  
Mohammad Aslam Mengal ◽  
Abdul Hafeez Qureshi ◽  
Parvez Ahmed ◽  
...  
Keyword(s):  
Comparative Study ◽  
External Fixation ◽  
External Fixator ◽  
Type Ii ◽  
Tibial Shaft ◽  
Interlocking Nail ◽  
Type Iiia ◽  
Type Iiib ◽  
Diaphyseal Fractures ◽  
Tibial Shaft Fractures

Objectives: To compare the external fixator and unreamed interlocking nail in treating Gustilo type II, type IIIA, and type IIIB tibial diaphyseal fractures regarding complications. Study Design: Cross-Sectional and Comparative Study. Setting: Department of Orthopaedic Surgery and Traumatology (DOST) Liaquat University of Medical and Health Sciences Jamshoro/Hyderabad. Period: Two years February 2016 to January 2018. Material & Methods: 40 cases of open tibia fractures in Patients of Gustilo type II, type IIIA, and type IIIB tibial diaphyseal fractures were included. The data were analyzed using the statistical program SPSS version 16.0. Results: A total of 23 cases were treated by external fixator and 22 cases were treated by unreamed solid interlocking nail. A total of 14 cases, that is, 31% showed delayed union. Type II injury 3/15 = 20%; Type IIIA injury 6/22 = 27.3%; Type IIIB injury it is -5/8 = 12.5%. For cases treated with unreamed nail, it was 22.7%; external fixator was 39.1% among 45 cases, 05 cases showed nonunion. For cases treated with unreamed nail, it was 13.6%; external fixation was 8.7%. The overall rate of eep infection is 11.1%. The rate in interlocking nail was 13.6%, and external fixation was 8.7%. Reoperation in the form of dynamization and bone graft application after 20 weeks in unreamed nail was 36.4%, whereas in external fixation the rate was high, almost 48%. The average time of union with unreamed interlocking was about 25.4 weeks, wherein external fixation it was 28.6 weeks. Conclusion: External fixators are a good and reliable method of stabilization of Gustilo type II, type IIIA, and type IIIB tibial diaphyseal fractures, unreamed interlocking intramedullary nail yields better results in treating Gustilo type II and type IIIA tibial shaft fractures.

scholarly journals Regional Analysis of Whole Cell Currents From Hair Cells of the Turtle Posterior Crista

2002 ◽  
Vol 88 (6) ◽  
pp. 3259-3278 ◽  
Author(s):  
Alan M. Brichta ◽  
Anne Aubert ◽  
Ruth Anne Eatock ◽  
Jay M. Goldberg
Keyword(s):  
Hair Cells ◽  
Central Zone ◽  
Peripheral Zone ◽  
Type I ◽  
Type Ii Cells ◽  
Type Ii ◽  
Fast Kinetics ◽  
Outward Currents ◽  
Inward Currents ◽  
Inwardly Rectifying

The turtle posterior crista is made up of two hemicristae, each consisting of a central zone containing type I and type II hair cells and a surrounding peripheral zone containing only type II hair cells and extending from the planum semilunatum to the nonsensory torus. Afferents from various regions of a hemicrista differ in their discharge properties. To see if afferent diversity is related to the basolateral currents of the hair cells innervated, we selectively harvested type I and II hair cells from the central zone and type II hair cells from two parts of the peripheral zone, one near the planum and the other near the torus. Voltage-dependent currents were studied with the whole cell, ruptured-patch method and characterized in voltage-clamp mode. We found regional differences in both outwardly and inwardly rectifying voltage-sensitive currents. As in birds and mammals, type I hair cells have a distinctive outwardly rectifying current ( IK,L), which begins activating at more hyperpolarized voltages than do the outward currents of type II hair cells. Activation of IK,Lis slow and sigmoidal. Maximal outward conductances are large. Outward currents in type II cells vary in their activation kinetics. Cells with fast kinetics are associated with small conductances and with partial inactivation during 200-ms depolarizing voltage steps. Almost all type II cells in the peripheral zone and many in the central zone have fast kinetics. Some type II cells in the central zone have large outward currents with slow kinetics and little inactivation. Although these currents resemble IK,L, they can be distinguished from the latter both electrophysiologically and pharmacologically. There are two varieties of inwardly rectifying currents in type II hair cells: activation of IK1is rapid and monoexponential, whereas that of Ihis slow and sigmoidal. Many type II cells either have both inward currents or only have IK1; very few cells only have Ih. Inward currents are less conspicuous in type I cells. Type II cells near the torus have smaller outwardly rectifying currents and larger inwardly rectifying currents than those near the planum, but the differences are too small to account for variations in discharge properties of bouton afferents innervating the two regions of the peripheral zone. The large outward conductances seen in central cells, by lowering impedances, may contribute to the low rotational gains of some central-zone afferents.

Sign in / Sign up

Export Citation Format

Share Document