Hyperpolarization-activated cyclic nucleotide-gated cation channel subtypes differentially modulate the excitability of murine small intestinal afferents

AIM： To assess the role of hyperpolarization-activated cyclic nucleotide-gated cation （HCN） channels in regu- lating the excitability of vagal and spinal gut afferents. METHODS： The mechanosensory response of mesen- teric afferent activity was measured in an ex vivo murine jejunum preparation. HCN channel activity was recorded through voltage and current clamp in acutely dissoci- ated dorsal root ganglia （DRG） and nodose ganglia （NG） neurons retrogradely labeled from the small intestine through injection of a fluorescent marker （DiI）. The isoforms of HCN channels expressed in DRG and NG neurons were examined by immunohistochemistry. RESULTS： Ramp distension of the small intestine evok- ed biphasic increases in the afferent nerve activity, re- flecting the activation of low- and high-threshold fibers.HCN blocker CsCl （5 mmol/L） preferentially inhibited the responses of low-threshold fibers to distension and showed no significant effects on the high-threshold re- sponses. The effect of CsCI was mimicked by the more selective HCN blocker ZD7288 （10 ~mol/L）. In 71.4% of DiI labeled DRG neurons （/7 = 20） and 90.9% of DiI labeled NG neurons （n = 10）, an inward current （Ih current） was evoked by hyperpolarization pulses which was fully eliminated by extracellular CsCI. In neurons expressing Ih current, a typical ＂sag＂ was observed upon injection of hyperpolarizing current pulses in cur- rent-clamp recordings. CsCI abolished the sag entirely. In some DiI labeled DRG neurons, the Ih current was potentiated by 8-Br-cAMP, which had no effect on the Ih current of DiI labeled NG neurons. Immunohistochem- istry revealed differential expression of HCN isoforms in vagal and spinal afferents, and HCN2 and HCN3 seemed to be the dominant isoform in DRG and NG, respec- tively.CONCLUSION： HCNs differentially regulate the excit- ability of vagal and spinal afferent of murine small in- testine.

SH2-B beta upregulates the expression of interleukin-1 beta in lung and visceral primary afferent neurons in asthmatic mice

A previous study by our research group showed that nerve growth factor is involved in the onset of asthma through regulating SH2-Bβ expression in the lung and visceral primary afferent neurons of asthmatic mice. This study sought to assess the expression level of interleukin-1β in primary afferent neurons in C7-T5 spinal ganglia, spinal cord and lung in asthmatic mice after blockage of SH2-Bβ. The levels of interleukin-1β protein in primary afferent neurons in the C7-T5 spinal ganglia and lung were decreased, and interleukin-1β mRNA expression also down-regulated in the spinal cord, medulla oblongata and lung tissue after blockage of SH2-Bβ. Our findings indicate that SH2-Bβ can upregulate the expression of interleukin-1β in C7-T5 spinal ganglia, spinal cord and lung of asthmatic mice.

Capsaicin-sensitive afferentation represents an indifferent defensive pathway from eradication in patients with H.pylori gastritis

AIM:To study the role of capsaicin-sensitive afferent nerves in Helicobacter pylori (H.pylori) positive chronic gastritis before and after eradication.METHODS:Gastric biopsy samples were obtained from corpus and antrum mucosa of 20 healthy human subjects and 18 patients with H.pylori positive chronic gastritis (n=18) before and after eradication.Tradi-tional gastric mucosal histology (and Warthin-Starry silver impregnation) and special histochemical examina-tions were carried out.Immunohistochemistry for cap-saicin receptor (TRVP1),calcitonin gene-related peptide (CGRP) and substance P (SP) were carried out by the labeled polymer immunohistological method (Lab VisionCo.,USA) using polyclonal rabbit and rat monoclonal antibodies (Abcam Ltd.,UK).RESULTS:Eradication treatment was successful in 16 patients (89%).Seven patients (7/18,39%) re-mained with moderate complaints,meanwhile 11 pa-tients (11/28,61%) had no complaints.At histological evaluation,normal gastric mucosa was detected in 4 patients after eradication treatment (4/18,22%),and moderate chronic gastritis could be seen in 14 (14/18,78%) patients.Positive immuno-staining for capsaicin receptor was seen in 35% (7/20) of controls,89% (16/18,P < 0.001) in patients before and 72% (13/18,P < 0.03) after eradication.CGRP was positive in 40% (8/20) of controls,and in 100% (18/18,P < 0.001) of patients before and in 100% (18/18,P < 0.001) after eradication.The immune-staining of gastric mucosa for substance-P was positive in 25% (5/20) of healthy con-trols,and in 5.5% (3/18,P > 0.05) of patients before and in 0% of patients (0/18,P > 0.05) after H.pylori eradication.CONCLUSION:Distibution of TRVP1 and CGRP is altered during the development of H.pylori positive chronic gastritis.The immune-staining for TRVP1,CGRP and SP rwemained unchanged before and after H.py-lori eradication treatment.The capsaicin-sensitive affer-entation is an independent from the eradication treat-ment.The 6 wk time period might not be enough time for the restituion of chronic H.pylori positive chronic gastritis.The H.pylori infection might not represent the main pathological factor in the development of chronic

Management of afferent loop obstruction: Reoperation or endoscopic and percutaneous interventions?

Afferent loop obstruction is a purely mechanical complication that infrequently occurs following construction of a gastrojejunostomy. The operations most commonly associated with this complication are gastrectomy with Billroth Ⅱ or Roux-en-Y reconstruction, and pancreaticoduodenectomy with conventional loop or Roux-en-Y reconstruction. Etiology of afferent loop obstruction includes:(1) entrapment, compression and kinking by postoperative adhesions;(2) internal herniation, volvulus and intussusception;(3) stenosis due to ulceration at the gastrojejunostomy site and radiation enteritis of the afferent loop;(4) cancer recurrence; and(5) enteroliths, bezoars and foreign bodies. Acute afferent loop obstruction is associated with complete obstruction of the afferent loop and represents a surgical emergency, whereas chronic afferent loop obstruction is associated with partial obstruction. Abdominal multiple detector computed tomography is the diagnostic study of choice. CT appearance of the obstructed afferent loop consists of a C-shaped, fluidfilled tubular mass located in the midline between the abdominal aorta and the superior mesenteric artery with valvulae conniventes projecting into the lumen. The cornerstone of treatment is surgery. Surgery includes:(1) adhesiolysis and reconstruction for benign causes; and(2) by-pass or excision and reconstruction for malignant causes. However, endoscopic enteral stenting, transhepatic percutaneous enteral stenting and direct percutaneous tube enterostomy have the principal role in management of malignant and radiation-induced obstruction. Nevertheless, considerable limitations exist as a former Roux-en-Y reconstruction limits endoscopic access to the afferent loop and percutaneous approaches for enteral stenting and tube enterostomy have only been reported in the literature as isolated cases.

Affer Effects遮罩局部调色技巧

运用影视后期制作软件Affer Effects对风景视频进行局部调色,可采用动态遮罩精确选取调色范围,再利用遮罩和层的混合模式进行调色。

Gastro-protective action of lafutidine mediated by capsaicin-sensitive afferent neurons without interaction with TRPV1 and involvement of endogenous prostaglandins

AIM： Lafutidine, a histamine H2 receptor antagonist, exhibits gastro-protective action mediated by capsaicinsensitive afferent neurons （CSN）. We compared the effect between lafutidine and capsaicin, with respect to the interaction with endogenous prostaglandins （PG）, nitric oxide （NO） and the afferent neurons, including transient receptor potential vanilloid subtype 1 （TRPV1）. METHODS： Male SD rats and C57BL/6 mice, both wildtype and prostacyclin IP receptor knockout animals, were used after 18 h of fasting. Gastric lesions were induced by the po administration of HCl/ethanol （60% in 150 mmol/L HCl） in a volume of 1 mL for rats or 0.3 mL for mice. RESULTS： Both lafutidine and capsaicin （1-10 mg/kg, po） afforded dose-dependent protection against HCI/ ethanol in rats and mice. The effects were attenuated by both the ablation of CSN and pretreatment with NG-nitro- L-arginine methyl ester, yet only the effect of capsaicin was mitigated by prior administration of capsazepine, the TRPV1 antagonist, as well as indomethacin. Lafutidine protected the stomach against HCl/ethanol in IP receptor knockout mice, similar to wild-type animals, while capsaicin failed to afford protection in the animals lacking IP receptors. Neither of these agents affected the mucosal PGE2 or 6-keto PGF1α contents in rat stomachs. Capsaicin evoked an increase in [Ca^2＋]i in rat TRPV1-transfected HEK293 cells while lafutidine did not. CONCLUSION： These results suggest that although both lafutidine and capsaicin exhibit gastro-protective action mediated by CSN, the mode of their effects differs regarding the dependency on endogenous PGs/IP receptors and TRPV1. It is assumed that lafutidine interacts with CSN at yet unidentified sites other than TRPV1.

Management of afferent loop obstruction from recurrent metastatic pancreatic cancer using a venting gastrojejunostomy

Pancreatic cancer is an aggressive malignancy poten-tially curable with surgical intervention. Following pan-creaticoduodenectomy for suspected pancreatic head malignancy, patients have a high risk for both immedi-ate and delayed problems due to surgical complica-tions and recurrent disease. We report here a patient with pancreatic cancer treated with pancreaticoduode-nectomy who developed recurrent disease resulting in obstruction of the afferent limb. The patient developed biliary obstruction and cholangitis at presentation. Her biliary tree failed to dilate which precluded safe percu-taneous biliary decompression. During surgical explo-ration, she was found to have a dilated afferent limb at the level of the transverse mesocolon. The patient underwent decompression of the afferent limb as well as the biliary tree using a venting gastrojejunostomy to the blind loop. This represents a novel surgical ap-proach for management of this complicated and diffi-cult problem.

Altered physiology of gastrointestinal vagal afferents following neurotrauma

The adaptability of the central nervous system has been revealed in several model systems.Of particular interest to central nervous system-injured individuals is the ability for neural components to be modified for regain of function.In both types of neurotrauma,traumatic brain injury and spinal cord injury,the primary parasympathetic control to the gastrointestinal tract,the vagus nerve,remains anatomically intact.However,individuals with traumatic brain injury or spinal cord injury are highly susceptible to gastrointestinal dysfunctions.Such gastrointestinal dysfunctions attribute to higher morbidity and mortality following traumatic brain injury and spinal cord injury.While the vagal efferent output remains capable of eliciting motor responses following injury,evidence suggests impairment of the vagal afferents.Since sensory input drives motor output,this review will discuss the normal and altered anatomy and physiology of the gastrointestinal vagal afferents to better understand the contributions of vagal afferent plasticity following neurotrauma.

Exposure to blast shock waves via the ear canal induces deficits in vestibular afferent function in rats

The ears are air-filled structures that are directly impacted during blast exposure.In addition to hearing loss and tinnitus,blast victims often complain of vertigo,dizziness and unsteady posture,suggesting that blast exposure induces damage to the vestibular end organs in the inner ear.However,the underlying mechanisms remain to be elucidated.In this report,single vestibular afferent activity and the vestibuloocular reflex(VOR)were investigated before and after exposure to blast shock waves(~20 PSI)delivered into the left external ear canals of anesthetized rats.Single vestibular afferent activity was recorded from the superior branch of the left vestibular nerves of the blast-treated and control rats one day after blast exposure.Blast exposure reduced the spontaneous discharge rates of the otolith and canal afferents.Blast exposure also reduced the sensitivity of irregular canal afferents to sinusoidal head rotation at 0.5e2Hz.Blast exposure,however,resulted in few changes in the VOR responses to sinusoidal head rotation and translation.To the best of our knowledge,this is the first study that reports blast exposure-induced damage to vestibular afferents in an animal model.These results provide insights that may be helpful in developing biomarkers for early diagnosis of blast-induced vestibular deficits in military and civilian populations.

Axonotmesis-evoked plantar vasodilatation as a novel assessment of C-fiber afferent function after sciatic nerve injury in rats

Quantitative assessment of the recovery of nerve function, especially sensory and autonomic nerve function, remains a challenge in the field of nerve regeneration research. We previously found that neural control of vasomotor activity could be potentially harnessed to evaluate nerve function. In the present study, five different models of left sciatic nerve injury in rats were established: nerve crush injury, nerve transection/ suturing, nerve defect/autografting, nerve defect/conduit repair, and nerve defect/non-regeneration. Laser Doppler perfusion imaging was used to analyze blood perfusion of the hind feet. The toe pinch test and walking track analysis were used to assess sensory and motor functions of the rat hind limb, respectively. Transmission electron microscopy was used to observe the density of unmyelinated axons in the injured sciatic nerve. Our results showed that axonotmesis-evoked vasodilatation in the foot 6 months after nerve injury/repair recovered to normal levels in the nerve crush injury group and partially in the other three repair groups;whereas the nerve defect/non-regeneration group exhibited no recovery in vasodilatation. Furthermore, the recovery index of axonotmesis-evoked vasodilatation was positively correlated with toe pinch reflex scores and the density of unmyelinated nerve fibers in the regenerated nerve. As C-fiber afferents are predominantly responsible for dilatation of the superficial vasculature in the glabrous skin in rats, the present findings indicate that axonotmesis-evoked vasodilatation can be used as a novel way to assess C-afferent function recovery after peripheral nerve injury. This study was approved by the Ethics Committee for Laboratory Animals of Nantong University of China (approval No. 20130410-006) on April 10, 2013.

Reactive oxygen species in paraventricular nucleus involved in cardiac sympathetic afferent reflex in rats

Objective： The present study was designed to determine if reactive oxygen species （ROS） in the paraventricular nucleus （PVN） were involved in modulating cardiac sympathetic afferent reflex （CSAR） in anesthetized rats. Methods： Malondialdehyde （MDA）, the end product of lipid peroxidation, in the PVN, was determined by thiobarbituric acid （TBA） spectrometric method. Renal sympathetic nerve activity （RSNA） and arterial pressure were recorded in sinoaortic-denervated and cervical-vagotomized rats. The CSAR was evaluated by the response of the RSNA evoked by epicardial application of bradykinin （BK, 0.4 9g）. Results： The MDA in the PVN was significantly increased after epicardial application of BK compared with control （2.0 ±0.3 vs 0.8 ±0.1 nmol/mg protein, P 〈 0.01）. Microinjection of a superoxide anion scavenger, tiron （20 nmol） into the PVN significantly inhibited the CSAR evoked by BK （12.3±1.9 vs4.2± 1.2%, P 〈0.01） and decreased MDA level （1.9±0.3 vs 0.6 ±0.1 nmol/mg protein, P 〈0.01） compared with control. Conclusion： The ROS in the PVN is involved in modulating the CSAR in rats.

Biliary stone causing afferent loop syndrome and pancreatitis

We report the case of an 84-year-old female who had a partial gastrectomy with Billroth-Ⅱ anastomosis 24 years ago for a benign peptic ulcer who now presented an acute pancreatitis secondary to an afferent loop syndrome. The syndrome was caused by a gallstone that migrated through a cholecystoenteric fistula. This is the first description in the literature of a biliary stone causing afferent loop syndrome.

Nerve growth factor in muscle afferent neurons of peripheral artery disease and autonomic function

In peripheral artery disease patients,the blood supply directed to the lower limbs is reduced.This results in severe limb ischemia and thereby enhances pain sensitivity in lower limbs.The painful perception is induced and exaggerate during walking,and is relieved by rest.This symptom is termed by intermittent claudication.The limb ischemia also amplifies autonomic responses during exercise.In the process of pain and autonomic responses originating exercising muscle,a number of receptors in afferent nerves sense ischemic changes and send signals to the central nervous system leading to autonomic responses.This review integrates recent study results in terms of perspectives including how nerve growth factor affects muscle sensory nerve receptors in peripheral artery disease and thereby alters responses of sympathetic nerve activity and blood pressure to active muscle.For the sensory nerve receptors,we emphasize the role played by transient receptor potential vanilloid type 1,purinergic P2X purinoceptor 3 and acid sensing ion channel subtype 3 in amplified sympathetic nerve activity responses in peripheral artery disease.

THE CORRELATION OF CENTRAL AFFERENT OF ACUPOINTS QUANLIAO(SI 18) AND SHIBAI(ST 2): TRANSGANGLIONIC DEGENERATIVE METHOD STUDY

Using transganglionic degenerative methed, we investigated the primary afferentinformation of acupoints of Quanliao (SI 18) and Shibai(ST 2). The results showed that the largeamounts of degenerative fibers could be found bilaterally in trigeminal spinal nucleus and its tract,trigeminal principal sensory nucleus, trigeminal mesencephalic nucleus and some degenerations couldbe observed ipsilaterally in solitary tract and its nucleus, medullary lateral reticular nucleus, giganto-cellular reticular nucleus and nucleus raphe magnus following transection of infraorbital nerve. A verymoderate degenerative fibers could be identifed in ipsilateral accessory spinal nucleus and spinal reticu-lar nucleus. A few degenerative fibers were seen on the contralateral magnocellular part of caudatepart of trigeminal spinal nucleus by passing through the posterior commissure of canalis centralis.These results suggest that the primary information of acupoints of Quanliao and Shibai could be trans-mittered into the above

Trigeminal primary afferent terminals containing substance P－like immunoreactivity in the paratrigeminal nucleus

With the methods of transganglionic transport of horseradish peroxidase(HRP) combined with postembedding colloidal gold stain immunoelectron microscopy, the shape and synaptic relationship of the trigeminal primary afferent terminals containing substance

THE ROLE OF NUCLEUS RAPHE MAGNUS IN THE ANTINOCICEPTIVE EFFECT OF MUSCLE SPINDLE AFFERENTS IN THE RAT

Objective To investigate the role of NRM in the antinociceptive effect of muscle spindle afferents,the influence of NRM lesion on the inhibitory effect of muscle spindle afferents on the nociceptive responses of wide dynamic range (WDR) neurons and the effects of the muscle spindle afferents on the NRM neuronal activities were observed. Methods The single units of WDR neurons in the spinal dorsal horn were recorded extracellularly, and the inhibitory effects of activating muscle spindle afferents by intravenous administration of succinylcholine (SCH) on the C fibers evoked responses (C responses) of WDR neurons were tested before and after lesion of NRM.The effects of the muscle spindle afferents activated by administrating SCH on the single NRM neurons were also examined.Results ①It was found that the C responses of WDR neurons were significantly inhibited by intravenously administration of SCH, and the inhibitory effect was reduced after lesion of NRM;②The activities of most of the NRM neurons could be changed significantly by administrating SCH. According to their responses, NRM neurons could be classified into three types:excitatory, inhibitory and non responsive neurons, and the responses were dose dependent. Conclusion These results suggest that the muscle spindle afferents evoked by SCH may activate the NRM neurons, which plays an important role in the antinociception of muscle spindle afferents.

Treatment of afferent loop syndrome using fluoroscopic-guided nasointestinal tube placement: Two case reports

BACKGROUND Afferent loop syndrome(ALS)is a rare mechanical complication that occurs after reconstruction of the stomach or esophagus to the jejunum,such as Billroth II gastrojejunostomy,Roux-en-Y gastrojejunostomy,or Roux-en-Y esophagojejunostomy.Traditionally,an operation is the first choice for benign causes.However,for patients in poor physical condition who experience ALS soon after R0 resection,the type of treatment remains controversial.Here,we present an efficient conservative method to treat ALS.CASE SUMMARY Case 1 was a 69-year-old male patient who underwent total gastrectomy with Roux-en-Y jejunojejunostomy.On postoperative day(POD)10 he developed symptoms of ALS that persisted and increased over 1 wk.Case 2 was a 59-yearold male patient who underwent distal gastrectomy with Billroth II gastrojejunostomy.On postoperative day POD 9 he developed symptoms of ALS that persisted for 2 wk.Both patients underwent fluoroscopic-guided nasointestinal tube placement with maintenance of continuous negative pressure suction.Approximately 20 d after the procedure,both patients had recovered well and were discharged from hospital after removal of the tube.At 3-mo follow-up,there were no signs of ALS in these two patients.CONCLUSION This is the first report of treating postoperative ALS by fluoroscopic-guided nasointestinal tube placement.Our cases demonstrate that this procedure is an effective and safe method to treat ALS that relieves patients’symptoms and avoids complications caused by other invasive procedures.

Fine-tuning of cortical progenitor proliferation by thalamic afferents

During cerebral cortical cortex neurogenesis two major types of progenitors generate a variety of morphologically and functionally diverse projection neurons destined for the different cortical layers in non-gyrified mice. Radial glia cells （RGCs） undergo mitosis in the cortical ventricular zone and exhibit an apical-basal cell polarity, whereas non-polar intermediate progenitor cells （IPCs） divide basally in the subventricular zone （Franco and Muller, 2013; Taverna et al., 2014）.

Clinical management for malignant afferent loop obstruction

Afferent loop obstruction(ALO)is defined as duodenal or jejunal mechanical obstruction at the proximal anastomosis site of a gastrojejunostomy.With advances in chemotherapy,the incidence of malignant ALO is increasing.Malignant ALO can be complicated by ischemia,gangrenous bowel,pancreatitis,and ascending cholangitis.Moreover,the general condition of patients with recurrent cancer is often poor.Therefore,accurate and rapid diagnosis and minimally invasive treatments are required.However,no review articles on the diagnosis and treatment of malignant ALO have been published.Through literature searching,we reviewed related articles published between 1959 and 2020 in the PubMed database.Herein,we present recent advances in the diagnosis and treatment of malignant ALO and describe future perspectives.Endoscopic transluminal self-expandable metal stent(SEMS)placement is considered the standard treatment for malignant ALO,as this procedure is well established and less invasive.However,with the development of interventional endoscopic ultrasound(EUS)in recent years,the usefulness of EUS-guided gastrojejunostomy has been reported.Moreover,through indirect comparison,this approach has been reported to be superior to transluminal SEMS placement.It is expected that a safer and less invasive treatment method will be established through the continued advancement and innovation of interventional endoscopy techniques.

SEGMENTAL DISTRIBUTION OF AFFERENT ELECTRO-ACUPUNCTURE SIGNALS FROM ACUPOINTS OF THE PERICARDIUM MERIDIAN IN THE RAT

Objective: To observe the segmental distribution of afferent Electroacupuncture (EA) signals from acupoints of the Pericardium (PC) Meridian and try to analyze the relative specificity of running route of PC Meridian.Methods: A total of 85 Wistar rats anesthetized with mixed solution of Chloralose (5 mg/100 g) and Urethane (42 mg/100g) were used in this study. Under microscopic observation, the micro-filaments of the distal end of the dorsal root were carefully separated after tearing the spinal pia mater to attach to a recording electrode. The reference electrode was placed beneath the skin of the incision. Two caudal and two rostral dorsal roots near the recorded one were cut off separately. Electrical activity of the isolated micro-filaments was observed before and after EA of "Daling" (PC 7) -"Jianshi" (PC 5), "Quze" (PC 3) of PC Meridian, "Yangchi"(TE 4)- "Zhigou" (TE 6), "Tianjing" (TE 10)-" Qin-glengyuan" (TE 11) of the Triple Energizer (TE) Meridian with electric current 1 mA and 2 mA and double pulses. Results: ① After EA (1 mA) of "Daling"(PC 7)-"Jianshi"(PC 5), the firing rates of 3 out of 10 (33.3%) micro-filaments in C5 segment, 5 out of 10 (50.0%) in C6, 7 out of 10 (70.0%) in 07, 3 out of 10 (30.0%) in C8 and 3 out of 13 (23. 1%) in T1 increased considerably；and after EA of "Quze" (PC 3), those of 3/10 of C5, 4/10 of C6, 6/10 of C7, 3/10 of C8, and 3/10 of T1 increased significantly. ② After EA (1 mA) of "Yangchi"(TE 4)- "Zhigou" (TE 6) and "Tianjing" (TE 10)- "Qinglengyuan" (TE 11). the firing rates of 2/10, 2/10 of micro-filaments In C5, 7/10, 3/10 of C6, 5/10 and 4/10 of C7, 1/10 and 1/10 of C8, and 2/13 and 1/10 of T1 increased significantly. It indicates that C7 dorsal root may play the first important role in conveying EA signals from PC Meridian acupoints to the spinal cord, while C6 and C7 may be mainly responsible for conveying EA signals from TE Meridian acupoints to the spinal cord. Conclusion: The peripheral afferent pathway for transmitting EA signals from PC Meridian acupoints probably has a relative specificity.