Electroacupuncture at Fengchi(GB20) inhibits calcitonin gene-related peptide expression in the trigeminovascular system of a rat model of migraine

Most migraine patients suffer from cutaneous allodynia; however, the underlying mechanisms are unclear. Calcitonin gene-related peptide(CGRP) plays an important role in the pathophysiology of migraine, and it is therefore, a potential therapeutic target for treating the pain. In the present study, a rat model of conscious migraine, induced by repeated electrical stimulation of the superior sagittal sinus, was established and treated with electroacupuncture at Fengchi(GB20)(depth of 2–3 mm, frequency of 2/15 Hz, intensity of 0.5–1.0 m A, 15 minutes/day, for 7 consecutive days). Electroacupuncture at GB20 significantly alleviated the decrease in hind paw and facial withdrawal thresholds and significantly lessened the increase in the levels of CGRP in the trigeminal ganglion, trigeminal nucleus caudalis and ventroposterior medial thalamic nucleus in rats with migraine. No CGRP-positive cells were detected in the trigeminal nucleus caudalis or ventroposterior medial thalamic nucleus by immunofluorescence. Our findings suggest that electroacupuncture treatment ameliorates migraine pain and associated cutaneous allodynia by modulating the trigeminovascular system ascending pathway, at least in part by inhibiting CGRP expression in the trigeminal ganglion.

The anti-inflammatory regulation of calcitonin gene-related peptide in mouse Aspergillus fumigatus keratitis

AIM:To analyze the impact of calcitonin gene-related peptide(CGRP)in mouse keratitis after Aspergillus fumigatus(A.fumigatus)infection.METHODS:C57 BL/6 mice were treated subconjunctivally with different concentrations of exogenous CGRP,and BALB/c mice were treated with CGRP8-37(a CGRP antagonist)before corneas were infected with A.fumigatus.The cornea was assessed under the slit-lamp and the clinical score was recorded.The mRNA levels of IL-1β,TNF-α,IL-6,and MIP-2 were detected by quantitative real-time polymerase chain reaction(PCR),while the protein level of IL-1βwas determined by Western blotting.In vitro,RAW264.7 cells were used to investigate NLRP3 and IL-1βexpression induced by A.fumigatus after the pretreatment of exogenous CGRP or CGRP8-37.Cytokines expression in RAW264.7 cells was evaluated by real-time PCR and Western blotting.RESULTS:Using exogenous CGRP resulted in downregulated synthesis of IL-1βand MIP-2 stimulated by A.fumigatus in C57 BL/6 mice keratitis,and the synthesis of IL-1β,MIP-2 and IL-6 was up-regulated in BALB/c mice corneas after the pretreatment with CGRP8-37.Pretreatment with exogenous CGRP and CGRP8-37 did not influence TNF-αmRNA levels either in BALB/c or C57 BL/6 mice keratitis.The levels of NLRP3 and IL-1βwere both reduced in A.fumigatus stimulated-macrophages after treatment with exogenous CGRP.And CGRP8-37 pretreatment would increase NLRP3 and IL-1βlevels.CONCLUSION:CGRP may alleviate the inflammatory reaction in mice keratitis after infection with A.fumigatus.The anti-inflammatory effect may be related to the inhibition of NLRP3 expression by CGRP.

EXPRESSION OF CALCITONIN GENE-RELATED PEPTIDE IN FACIAL NERVE OF HEMIFACIAL SPASM

Objective To study the immunoreactivity of Calcitonin gene-related peptide (CGRP) in the facial nerve when Hemifacial Spasm is occurring. Methods The electrophysiological technique was used to explore abnormal muscle response (AMR) which was characteristic of Hemifacial Spasm.The animal models of Hemifacial Spasm in New Zealand white rabbits were established by compressing the main trunk of artificial demyelinated facial nerve with the temporal superficial artery. At 6 weeks after surgery, the facial nerves were taken from the experimental group and control one, the immunohistochemistry for CGRP using polyclonal antibody with ABC kit was performed in the facial nerves; at the same time, the observation for the facial nerves of light and transmission electron microscope was performed. Results The facial nerve demyelinated and the axons retrogressively changed, CGRP immunoreactive positive fibers were significantly detected in experimental groups; whereas this phenomenon was not found in control group. Conclusion CGRP can nutrien the injured facial nerve and plays an important role in the pathogenesis of Hemifacial Spasm.

Effect of calcitonin gene-related peptide and nerve growth factor on spatial learning and memory abilities of rats following focal cerebral ischemia/reperfusion

BACKGROUND: Calcitonin gene-related peptide (CGRP) and nerve growth actor (NGF) cam improve spatial learning and memory abilities of rats with cerebral ischemia/reperfusion; however, the effect of combination of them on relieving learning and memory injury following cerebral ischemia/reperfusion should be further studied. OBJECTIVE: To study the effects of exogenous CGRP and NGF on learning and memory abilities of rats with focal cerebral ischemia/reperfusion. DESIGN: Randomized controlled animal study. SETTING: Department of Neurosurgery, the Second Hospital of Xiamen; Department of Neurosurgery, the Second Affiliated Hospital of China Medical University; Department of Neurobiology, Basic Medical College of China Medical University. MATERIALS: A total of 30 healthy male SD rats, aged 8 weeks, of clean grade, weighing 250-300 g, were provided by Experimental Animal Department of China Medical University. All rats were randomly divided into sham-operation group, ischemia/reperfusion group and treatment group with 10 in each group. The main reagents were detailed as the follows: 100 g/L chloral hydrate, 0.5 mL CGRP (2 mg/L, Sigma Company, USA), and NGF (1× 106 U/L, 0.5 mL, Siweite Company, Dalian). METHODS: The experiment was carried out in the Department of Neurobiology, Basic Medical College of China Medical University from February to July 2005. Rat models of middle cerebral artery occlusion were established by method of occlusion, 2 hours after that rats were anesthetized and the thread was slightly drawn out for 10 mm under direct staring to perform reperfusion. Rats in the ischemia/reperfusion group received intraperitoneal injection of 1 mL saline via the abdomen at two hours later, while rats in the treatment group at 2 hours later received intraperitoneal injection of 2 mg/L CGRP (0.5 mL) and 1×106 U/L NGF (0.5 mL) once a day for 10 successive days. First administration was accomplished within 15 minutes after ischemia/reperfusion. Rats in the sham-operation group were separated of the vessels without occlusion or administration. The neural function was evaluated with Zea Longa 5-grade scale. Animals with the score of one, two and three points received Morris water-maze test to measure searching time on platform (omitting platform-escaping latency). Meanwhile, leaning and memory abilities of animals were reflected through testing times of passing through platform per minute. MAIN OUTCOME MEASURES: Experimental results of omitting platform-escaping latency and spatial probe. RESULTS: Three and two rats in the ischemia/reperfusion group and treatment group respectively were not in accordance with the criteria in the process, and the rest were involved in the final analysis. ① Comparisons of platform-escaping latency during Morris water-maze test in all the three groups: Ten days after modeling, the platform-escaping latency in the ischemia/reperfusion group was obviously longer than that in sham-operation group (P < 0.01), and was significantly shorter than that in the treatment group (P < 0.01). ② Comparisons of times of passing through platform in all the three groups: Times of passing through platform were remarkably less in the ischemia/reperfusion group than those in the sham-operation group [(1.79±0.39), (4.30±0.73) times/minute, P < 0.01], and those were markedly more in the treatment group than the ischemia/reperfusion group [(3.16±1.03), (1.79±0.39) times/minute, P < 0.01]. CONCLUSION: CGRP and NGF are capable of ameliorating the abilities of spatial learning and memory in MCAO rats, which indicates that CGRP and NGF can protect ischemic neurons.

Xiongzhi Dilong decoction interferes with calcitonin gene-related peptide(CGRP)-induced migraine in rats through the CGRP/iNOS pathway

Objective: To evaluate the effects of Xiongzhi Dilong decoction(XZDLD) and its wind medicine on calcitonin gene-related peptide(CGRP)-induced migraine and explore the mechanism through the CGRP/inducible nitric oxide synthase(iNOS) pathway.Methods: Rats were divided into control, model, XZDLD, XZDLD(external wind), XZDLD(internal wind),and olcegepant groups. CGRP was injected into the dura mater to induce a migraine. The frequency of head scratching, cage climbing, and facial grooming was observed. The pain threshold, the levels of CGRP,pituitary adenylate cyclase activating polypeptide(PACAP), substance P(SP), and the plasma protein extravasation(PPE) ratio were measured. The phosphorylation levels of p38, extracellular signalregulated kinase 1/2(ERK1/2), and expression of iNOS were detected by western blot.Results: Compared with the model group, the three modified XZDLD groups showed reduced frequency of head scratching and cage climbing in the first 30 min(all P <.05). Facial grooming frequency was reduced in XZDLD and XZDLD(external wind) groups(P =.0003 and P =.0131, respectively). External wind medicine played a more important role in increasing mechanical pain threshold than internal wind medicine. Moreover, compared with the model group, the three modified XZDLD groups demonstrated reduced plasma levels of CGRP and PACAP(all P <.05). No difference in the SP level was observed among the six groups. XZDLD reduced PPE ratio. XZDLD and XZDLD(external wind) groups suppressed the CGRP/iNOS pathway by inhibiting the p-p38/p38 ratio and the expression of iNOS. No difference in pERK1/2/ERK1/2 ratio was detected among the six groups.Conclusion: XZDLD increases pain threshold, downregulates the expression of CGRP and PACAP, and reduces PPE ratio by inhibiting the CGRP/iNOS pathway. External wind medicine is more effective than internal one on improving facial grooming and head scratching, increasing the mechanical pain threshold, and inhibiting the expression of iNOS.

Changes of calcitonin gene-related peptide and other serological indicators in vestibular migraine patients

Objective:It aims to evaluate the diagnostic ability of CGRP and other blood indicators in vestibular migraine(VM)patients,and to explain the potential pathological effects of these biomarkers.The hypothesis of VM being a variant of migraine was examined.Methods:A total of 32 VM patients,35 migraine patients,and 30 healthy control subjects(HC)were selected for this cross-sectional study.Detailed statistics on demographic data,clinical manifestations,calcitonin gene-related peptide(CGRP)and common clinical laboratory indicators were measured within 24 hours from the onset of the conditions.Receptor operating characteristic(ROC)curve and area under the curve(AUC)were analyzed for biomarkers.The risk factors of VM and migraine were determined through univariate and multivariate analyses.Results:Compared with HC,serum CGRP levels(p(VM)=0.012,p(Migraine)=0.028)increased and Mg^(2+)levels(p(VM)<0.001,p(Migraine)<0.001)deceased in VM patients and migraine patients.In multiple logistic regression,VM was correlated with CGRP[odds ratio(OR)=1.07;95%confidence interval(CI),1.02-1.12;P=0.01]and Mg^(2+)[odds ratio(OR)=0.03;95%CI,0.07-0.15;P<0.001].Migraine was correlated with CGRP[odds ratio(OR)=1.07;95%CI,1.02-1.12;P=0.01]and Mg^(2+)[odd ratio(OR=0.01;95%CI,0-0.02;P<0.001)].Mg^(2+)discriminated good differentiation between VM and migraine groups,with AUC of 0.649(95%CI,0.518 to 0.780).The optimal threshold for Mg^(2+)to diagnose VM was 0.805.Conclusions:This study demonstrated that CGRP and Mg^(2+)may be promising laboratory indicators to discriminate HC from VM/migraine,while Mg^(2+)may be uded as a discriminator between VM and migraine.

Calcitonin gene-related peptide and traumatic brain injury

Dear editor,It is with great interest that we read the article“Relationship of calcitonin gene-related peptide with disease progression and prognosis of patients with severe traumatic brain injury”(Chen et al.,2018).In this study,the authors evaluated 121 patients who were divided into mild/moderate traumatic brain injury(TBI)(n=61),severe TBI(n=35)and control(n=25)groups,and measured serum levels of calcitonin gene-related peptide(CGRP)and serum endothelin-1(ET-1).They found that low levels of CGRP and high levels of ET-1 were associated with high mortality at 6 months.Identification of morphological abnormalities on CT scans is very important for evaluating patients with TBI because different diagnoses are made based on different imaging findings(Maas et al.,2005).

Expression and role of calcitonin gene-related peptide in mouse Aspergillus fumigatus keratitis

AIM: To investigate the expression and role of calcitonin gene-related peptide(CGRP) in the mouse models induced by Aspergillus fumigatus(A. fumigatus). METHODS: C57 BL/6 mice were randomized into a control group and A. fumigatus keratitis group. The cornea photography was assessed under the slit lamp and the clinical score was recorded after infection. Western blot, real-time polymerase chain reaction(PCR) and immunohistofluorescence analysis were applied to detect CGRP expression in cornea of both groups. In vitro, tests were conducted with C57 BL/6 mice macrophages to investigate CGRP expression after interaction with A. fumigatus. Cytokines expression induced by exogenous CGRP and the antagonist CGRP8-37 in A. fumigatus-exposed macrophages was evaluated by real-time PCR and ELISA.RESULTS: The cornea expression of CGRP was significantly elevated in C57 BL/6 mice corneas and macrophages after A. fumigatus infection. After treatment with exogenous CGRP, the levels of interleukin-1β(IL-1β), tumor necrosis factor-α(TNF-α) and IL-6 were reduced, and IL-10 level was increased in the A. fumigatus stimulatedmacrophages. However, IL-1β, TNF-α and IL-6 levels were upregulated after pretreatment of CGRP8-37. But the m RNA levels of MIP-2, TGF-β and IL-10 were not changed. CONCLUSION: This study provides evidence that A. fumigatus increased CGRP expression. CGRP may play a protective role against inflammation in A. fumigatus keratitis.

Preliminary study on androgen dependence of calcitonin gene-related peptide in rat penis

Aim: To study the androgen dependence of the neurotransmitter, calcitonin gene-related peptide (CGRP) in rat penis. Methods: Forty-four Sprague-Dawley rats were randomly divided into Group A (intact controls), Group B (castrated) and Group C (gavaged with finasteride 4.5 mg·kg^-1·day^-1). Four and ten weeks later respectively, half of rats in each group were anaesthetized. Blood samples were taken for the measurement of serum testosterone and dihydrotestosterone (DHT) by means of radioimmunoassay. Penile samples were harvested for the investigation of calcitonin gene related peptide (CGRP)-immunoreactive nerve fibers with immunohistochemistry. The computer-assisted imaging analysis system was applied to calculate the area proportion of the CGRP-positive nerve fibers (CGRP-PNF) in each group. Results: 1) Both 4 and 10 weeks later, testosterone and DHT levels in Group B decreased significantly compared with those in Group A, (P < 0.05, P < 0.01, respectively); DHT level in Group C was also significantly decreased in comparison with that in Group A for both 4- and 10- week animals (P < 0.05); 2) There was no significant differences in area proportion of CGRP-PNF among Groups A, B and C 4 weeks after treatments (P > 0.05); However, 10 weeks later, the proportion of CGRP-PNF in Groups B and C was significantly less than that in Group A (P < 0.01 ); 3) The proportion of CGRP-PNF of 4-week animals in Groups B and C was significantly higher than that of 10-week animals (P < 0.05). Conclusion: The expression of neurotransmitter, CGRP may depend on androgens, including testosterone and DHT in rat penis.

Effect of warm acupuncture on nitric oxide synthase and calcitonin gene-related peptide in a rat model of lumbar nerve root compression

BACKGROUND:Varying degrees of inflammatory responses occur during lumbar nerve root compression.Studies have shown that nitric oxide synthase(NOS) and calcitonin gene-related peptide(CGRP) are involved in secondary disc inflammation. OBJECTIVE:To observe the effects of warm acupuncture on the ultrastructure of inflammatory mediators in a rat model of lumbar nerve root compression,including NOS and CGRP contents. DESIGN,TIME AND SETTING:Randomized,controlled study,with molecular biological analysis, was performed at the Experimental Center,Sixth People's Hospital Affiliated to Shanghai Jiao Tong University,between September 2006 and April 2007. MATERIALS:Acupuncture needles and refined Moxa grains were purchased from Shanghai Taicheng Technology Development Co.,Ltd.,China;Mobic tablets were purchased from Shanghai Boehringer Ingelheim Pharmaceuticals Co.,Ltd.,China;enzyme linked immunosorbent assay (ELISA) kits for NOS and CGRP were purchased from ADL Biotechnology,Inc.,USA. METHODS:A total of 50,healthy,adult Sprague-Dawley rats,were randomly divided into five groups normal,model,warm acupuncture,acupuncture,and drug,with 10 rats in each group.Rats in the four groups,excluding the normal group,were used to establish models of lumbar nerve root compression.After 3 days,Jiaji points were set using reinforcing-reducing manipulation in the warm acupuncture group.Moxa grains were burned on each needle,with 2 grains each daily.The acupuncture group was the same as the warm acupuncture group,with the exception of non-moxibustion.Mobic suspension(3.75 mg/kg) was used in the oral drug group,once a day. Treatment of each group lasted for 14 consecutive days.Modeling and medication were not performed in the normal group. MAIN OUTCOME MEASURES:The ultrastructure of damaged nerve roots was observed with transmission electron microscopy;NOS and CGRP contents were measured using ELISA. RESULTS:The changes of the radicular ultramicrostructure were characterized by Wallerian degeneration;nerve fibers were clearly demyelinated;axons collapsed or degenerated;outer Schwann cell cytoplasm was swollen and its nucleus was compacted.Compared with the normal group,NOS and CGRP contents in the nerve root compression zone in the model group were significantly increased(P<0.01).Nerve root edema was improved in the drug,acupuncture and the warm acupuncture groups over the model group.NOS and CGRP expressions were also decreased with the warm acupuncture group having the lowest concentration(P<0.01). CONCLUSION:In comparison to the known effects of Mobic drug and acupuncture treatments,the warm acupuncture significantly decreased NOS and CGRP expression which helped improve the ultrastructure of the comoressed nerve root.

Relationship among plasma endothelin, calcitonin gene-related peptide and blood flow rate of bilateral vertebral arteries in patients with cervical vertigo

Objective: To investigate the relationship among plasma endothelin(ET), calcitonin gene-related peptide(CGRP) and blood flow rate of bilateral vertebral arteries in patients with cervical vertigo(CV) and to assess the effect of ET and CGRP on the onset of CV. Methods:The concentration of ET and CGRP in 64 patients with CV and 30 controls was determined by radioimmunity method. The average blood flow velocity (Vm) of bilateral vertebral arteries was detected by Transcranial Doppler(TCD). Results:Plasma concen- tration of ET(91.48± 9.08 pg/ml) and ET/CGRP ratio value(2.88± 0.52) in vertebrobasilar arteriospasm group were both higher than those in vertebrobasilar non-arteriospasm group and in controls, while CGRP concentration(30.66± 6.05 pg/ml) in vertebrobasilar arteriospasm group was lower than that in vertebrobasilar non-arteriospasm group and controls respectively. The Vm of bilateral verte- bral arteries in vertebrobasilar arteriospasm group(67.97± 11.64 cm/s ) was higher than that in vertebrobasilar non-arteriospasm group and controls respectively, having a positive correlation with ET concentration and ET/CGRP ratio value(r1=0.52, P < 0.05; r2=0.59, P < 0.05), but a negative correlation with CGRP concentration(r3=-0.54, P < 0.05). There was no significant difference in ET and CGRP concentration, ET/CGRP ratio value and the Vm of bilateral vertebral arteries between vertebrobasilar non-arteriospasm group and the control group. Conclusion: All the results indicate that ET and CGRP are possibly the most important substance factors at the onset of CV with vertebrobasilar arteriospasm, and their imbalance of regulating vertebrobasilar arterial contraction and relaxation may play an important role in the onset of CV with vertebrobasilar arteriospasm.

Calcitonin gene-related peptide in anterior and posterior horns of spinal cord after brachial plexus injury

BACKGROUND:The changes of calcitonin gene-related peptide(CGRP)expression are closely associated with peripheral nerve injury,whereas it should be further investigated whether the damage of central nerve can lead to the changes of CGRP expression,and whether it is associated with the neural regeneration and repair.OBJECTIVE:To observe the changing law of CGRP expression in the anterior and posterior horns of spinal cord following brachial plexus injury.DESIGN:A randomized controlled trial.SETTINGS:Department of Anatomy,Yunyang Medical College;Department of Anatomy,Basic Medical College,Sun Yat-sen University.MATERIALS:Sixty-five adult male SD rats of clean degree,weighing 180-220 g,provided by the experimental animal center of the Basic Medical College,Sun Yat-sen University,were randomly divided into control group(n =5)and experimental group(n =60),and the latter was subdivided into three damage groups:avulsion of anterior root group(n =20),disjunction of posterior root group(n =20)and transection of spinal cord group(n =20).Diaminobenzidine(DAB)chromogen,rabbit anti-CGRP polyclonal antibody were the products of Sigma Company;Leica image analytical apparatus was produced by QUIN Company(Germany);Histotome by Sigma Company.METHODS:The experiments were carried out in the Department of Anatomy,Basic Medical College,Sun Yat-sen University from September 2004 to March 2005.Three kinds of models of brachial plexus injury were established:In the avulsion of anterior root group,right C7 anterior root was avulsed,and the distal nerve residual root was transected.In the disjunction of posterior root group,right C7 anterior root was avulsed and right C5-T1 posterior horns were cut to block the sensory afferent pathway.In the transection of spinal cord group,right C7 anterior root was avulsed and C5-6 segments of right spinal cord were semi-transected to block the cortical descending pathway.In the control group,C5-T1 vertebral plates were prayed open,and then the skin was sutured.The C7 segments of spinal cord were removed on the 1st,3rd,7th and 14th days postoperatively respectively,and the CGRP expressions in the anterior and posterior horns of spinal cord were determined and analyzed using immunohistochemical method and image analysis.MAIN OUTCOME MEASURES:① Number of CGRP immuno-positive motor neurons in the anterior horn of spinal cord;② Total area of CGRP immuno-positive fibers in the posterior horn of spinal cord.RESULTS:All the 65 rats were involved in the analysis of results.① Number of CGRP immuno-positive motor neurons in the anterior horn of spinal cord:CGRP immuno-positive motor neurons could be observed in the anterior horns of C7 spinal cord in the control group and damage groups,the neurons had big cell body with stained cytoplasm,appeared as brown granules,and mainly distributed in the ventral lateral anterior horn of spinal cord.On the 1st day postoperatively,the number of CGRP positive neurons was obviously higher in the in the avulsion of anterior root group than in the control group(P < 0.01),whereas obviously lower in the disjunction of posterior root group than in the control group(P < 0.01),and there was no obvious difference between the transection of spinal cord group and the control group(P > 0.05).On the 7th day,the numbers of CGRP positive neurons in the damage groups were obviously higher than that in the control group(P < 0.01),also obviously different from those on the 1st day in the same group respectively(P < 0.01).On the 14th day,the number of CGRP positive neurons in the disjunction of posterior root group was decreased,but there was no obvious difference as compared with that in the control group,whereas those in the avulsion of anterior root group and transection of spinal cord group were still obviously higher than that in the control group(P < 0.01).The number of CGRP positive neurons was the most in the avulsion of anterior root group,followed by the transection of spinal cord group,and the least in the disjunction of posterior root group,and there were significant differences among them(P < 0.01).② Total area of CGRPimmuno-positive fibers in the posterior horn of spinal cord:Dense CGRP immuno-positive nerve fibers distributed in the layers Ⅰ and Ⅱ of the C7 posterior horn of spinal cord in the control group.On the 1st day postoperatively,the total areas of CGRP positive fibers in the avulsion of anterior root group and transection of spinal cord group were obviously larger than that in the control group(P < 0.01),whereas there was no obvious difference between the disjunction of posterior root group and control group.On the 7th day,the CGRP expression in the posterior horn of spinal cord decreased to the lowest level in the disjunction of posterior root group,whereas there were no obvious differences in the avulsion of anterior root group and transection of spinal cord group as compared with that in the control group(P > 0.05).On the 14th day,the area continued to decrease in the avulsion of anterior root group and transection of spinal cord group,and it was obviously lower in the transection of spinal cord group than in the control group(P < 0.01),and it was slightly increased in the disjunction of posterior root group as compared with that on 7th day,but still obviously lower than that in the control group(P < 0.01).CONCLUSION:The expression and role of CGRP are in discrepancy in the anterior and posterior horns of spinal cord after brachial plexus injury.The CGRP in anterior horn of spinal cord are derived from the cell body of motor neurons,and may be involved in the repairing mechanism of nerve injury regeneration;Whereas those in the posterior horn are mainly derived from posterior root ganglion,and may be associated with the conduction of noxious stimulations.

Relationship of calcitonin gene-related peptide with disease progression and prognosis of patients with severe traumatic brain injury

Calcitonin gene-related peptide(CGRP) has been implicated in multiple functions across many bioprocesses; however, whether CGRP is associated with severe traumatic brain injury(TBI) remains poorly understood. In this study, 96 adult patients with TBI(enrolled from September 2015 to December 2016) were divided into a mild/moderate TBI group(36 males and 25 females, aged 38 ± 13 years) and severe TBI group(22 males and 13 females, aged 38 ± 11 years) according to Glasgow Coma Scale scores. In addition, 25 healthy individuals were selected as controls(15 males and 10 females, aged 39 ± 13 years). Radioimmunoassay was used to detect serum levels of CGRP and endothelin-1 at admission and at 12, 24, 48, 72 hours, and 7 days after admission. CGRP levels were remarkably lower, but endothelin-1 levels were obviously higher in the severe TBI group compared with mild/moderate TBI and control groups. Levels of CGRP were remarkably lower, but endothelin-1 levels were obviously higher in deceased patients compared with patients who survived. Survival analysis and logistic regression showed that both CGRP and endothelin-1 levels were associated with patient mortality, with each serving as an independent risk factor for 6-month mortality of severe TBI patients. Moreover, TBI patients with lower serum CGRP levels had a higher risk of death. Thus, our retrospective analysis demonstrates the potential utility of CGRP as a new biomarker, monitoring method, and therapeutic target for TBI.

Substance P and calcitonin gene-related peptide expression in dorsal root ganglia in sciatic nerve injury rats

The neuropeptides,substance P and calcitonin gene-related peptide,have been shown to be involved in pain transmission and repair of sciatic nerve injury.A model of sciatic nerve defect was prepared by dissecting the sciatic nerve at the middle,left femur in female Sprague Dawley rats.The two ends of the nerve were encased in a silica gel tube.L 5 dorsal root ganglia were harvested 7,14 and 28 days post sciatic nerve injury for immunohistochemical staining.Results showed that substance P and calcitonin gene-related peptide expression increased significantly in dorsal root ganglion of rats with sciatic nerve injury.This increase peaked at 7 days,declined at 14 days,and reduced to normal levels by 28 days post injury.The findings indicate that the neuropeptides,substance P and calcitonin gene- related peptide,mainly increased in the early stages after sciatic nerve injury.

Correlation of calcitonin gene-related peptide and endothelin receptor A with subarachnoid hemorrhage

Numerous studies have demonstrated that endothelin-1 combines with endothelin receptor A,resulting in intense vasoconstriction.Although calcitonin gene-related peptide(CGRP) suppresses endothelin-1,CGRP and endothelin receptor A exhibit direct biological effects on brain tissue.The present study analyzed CGRP and endothelin receptor A expression following subarachnoid hemorrhage in rabbits using immunohistochemistry.CGRP expression was significant at 5 days after model establishment,and endothelin receptor A expression was significant at 3 days after model induction.The perimeter of the basilar artery was measured to determine the amount of cerebral vasospasm.Analytical results revealed a significantly shortened basilar artery perimeter following subarachnoid hemorrhage.Changes in the basilar artery perimeter were negatively associated with endothelin receptor A expression,but positively correlated with CGRP expression in vessels.These results suggest that following subarachnoid hemorrhage,CGRP and endothelin receptor A expressions dynamically changed in brain vessels and tissues,although these changes were not synchronous.Changes in endothelin receptor A expression exhibited a significant effect on the occurrence and development of delayed cerebral vasospasm and delayed neuronal death,while CGRP relaxed vessels and protected nerves.

Co-existence of calcitonin gene-related peptide (CGRP) and 5-hydroxytryptamin (5-HT) in rabbit lung

It was investigated that the localization and distribution of calcitonin gene-relatedpeptide (CGRP) in the rabbit lung by ABC-GDN immunohistochemistry.The results demon-strated that CGRP immunoreactivity was located in neuroendocrine cells (NEC_s) and neu-roepthelial bodies (NEB_s),including all airways from bronchi,bronchioles,and alveolar ducts.The nerve fibers in walls of the intrapulmonary bronchi and blood vessels also had CGRP-immunoreactivity.Adjacent sections immunostained with antibodies to CGRP and 5-HT provedthe coexistence of CGRP and 5-HT in NECs and NEBs.This finding suggested the possibilityof functional interaction between the peptide and amine.

Changes in plasma calcitonin gene-related peptide and serum neuron specific enolase in rats with acute cerebral ischemia after low-frequency electrical stimulation with different waveforms and intensities

Following acute cerebral ischemia in rats,plasma calcitonin gene-related peptide decreased and the level of serum neuron specific enolase and the volume of the infarction increased.Square-wave and triangular-wave electrical stimulation with low or high intensities could increase the plasma calcitonin gene-related peptide,decrease the serum neuron specific enolase and reduce the infarction volume in the brain in rats with cerebral ischemia.There was no significant difference between different wave forms and intensities.The experimental findings indicate that low-frequency electrical stimulation with varying waveforms and intensities can treat acute cerebral ischemia in rats.

Transient receptor potential channel A1 involved in calcitonin gene-related peptide release in neurons

Transient receptor potential channel A1 is one of the important transducers of noxious stimuli in the primary afferents,which may contribute to generation of neurogenic inflammation and hyperalgesia.The present study was designed to investigate if activation of transient receptor potential channel A1 may induce calcitonin gene-related peptide release from the primary afferent neurons.We found that application of allyl isothiocyanate,a transient receptor potential channel A1 activator,caused calcitonin gene-related peptide release from the cultured rat dorsal root ganglion neurons.Knockdown of transient receptor potential channel A1 with an antisense oligodeoxynucleotide prevented calcitonin gene-related peptide release by allyl isothiocyanate application in cultured dorsal root ganglion neurons.Thus,we concluded that transient receptor potential channel A1 activation caused calcitonin gene-related peptide release in sensory neurons.

The inhibitory effect of calcitonin gene-related peptide on adriamycin induced acute cardiotoxicity in cultured myocardial cells

Objective: To observe the inhibitory effect of calcitonin gene--related peptide (CGRP) on adriamycininduced acute cardiotoxicity. Methods: Primarily cultured rat myocardial cells were treated with 10-6 mol/Ladriamycin and 10-6mol/L adriamycin + 10 8mol/I. CGRP. Lactate dehydrogenase (LDH ) activity in the mediumand the contents of malondialdehyde (MDA ). calcium. and magnesium in the myocardial cells were assayed.Results: In the adriamycin group, LDH activity in medium and calcium, MDA contents in myocardial cells weresignificantly increased compared with those in control group, and magnesium content in the myocardial cells wassignificantly reduced. In the adriamycin group. there was a positive correlation between LDH activity in themedium and MDA content in the myocardial cells. Meanwhile, in the adriamycin + CGRP group,- CGRP mightsignificantly reduce the leakage of LDH from myocardial cells, lessen the increase in calcium and MDA contentsand prevent the loss of magnesium. Conclusion: CGRP may inhibit adriamycin induced acute cardiotoxicity byinhibiting lipid peroxidation, attenuating calcium overload, magnesium loss, and protecting enzyme activity.

CALCITONIN GENE-RELATED PEPTIDE INDUCES FIBRO-BLASTS FROM HIP PSEUDOCAPSULE TO PRODUCE CYTOKINES

Objective To investigate calcitonin gene-related peptide (CGRP) involvement in the process of aseptic loosening. Methods We isolated fibroblasts from periprosthetic pseudocapsular tissue at the time of revision hip arthroplasty performed due to aseptic loosening. Fibroblasts were incubated for 24 h in the presence of CGRP, and the levels of interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α in the media were determined using enzyme-linked immunosorbent assay kit. Results We found that the levels of IL-1β, IL-6, and TNF-α increased in a time-and concentration-dependent manner. ConclusionThese inflammatory cytokines play an important role in the development of periprosthetic osteolysis and implant loosening. Our results suggest that CGRP may be involved in the pathogenesis of aseptic loosening.