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Objective@#To study the role of corticotropin-releasing hormone (CRH) system in locus ceruleus (LC) in irritable bowel syndrome (IBS) and to explore its molecular mechanism.@*Methods@#The IBS rat was established by maternal separation following with postnatal stress. The tissues sample of LC was obtained by micropunched nuclei. The expression of c-Fos, CRH and its receptors including corticotropin-releasing hormone receptor (CRHR) 1 and CRHR2 of rats’ LC tissues of control group and IBS group was detected by quantitative polymerase chain reaction(PCR). The expression of DNA methyltransferase (DNTM) 1, DNMT3a and DNMT3b at the mRNA level were also measured. In addition, the expression of histone methyltransferase ASH2-like protein (ASH2L) and SET and MYND domain containing 2 (SMYD2) was determined by Western blotting. T test was used for statistical analysis.@*Results@#The rectal pneumatic pressure of IBS group was lower than that of control group ((69.82±5.47) mmHg vs. (86.86±5.98) mmHg; 1 mmHg=0.133 kPa), however compared with that of control group, the expression of c-Fos at the mRNA level increased (2.11±0.44 vs.1.00±0.19), and the differences were statistically significant (t=6.215 and 2.321, P<0.01 and 0.05). In addition, compared with that of control group, the expression of CRH at the mRNA level increased (1.99±0.35 vs.1.00±0.13), and the difference was statistically significant (t= 2.797, P<0.05). Compared with that of control group, the expression of SMYD2 at the protein level up-regulated (1.04±0.21 vs. 0.61±0.12), and the difference was statistically significant (t=4.451, P<0.01). However, there were no statistically significant differences in the expression of CRHR-1, CRHR2, DNMT1, DNMT3a, DNMT3b at the mRNA level, and the expression of ASH2L between IBS group and control group (0.96±0.13 vs. 1.00±0.26, 1.35±0.63 vs. 1.00±0.43, 1.40±0.61 vs.1.00±0.19, 1.39±0.58 vs. 1.00±0.21, 1.45±0.71vs.1.00±0.39 and 0.80±0.19 vs. 1.05±0.26, respectively; all P>0.05).@*Conclusions@#Maternal separation combined with postnatal stress affect the transcription of Crh gene in LC and cause the activation of the stress regulation network CRH and norepinephrine system, resulting in the increase of the visceral sensitivity of rats. The abnormal transcription of Crh gene may be related with SMYD2-mediated histone H3K36 methylation, but not related with the modification of DNA methylation.
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Objective To investigate expression changes of nuclear receptors-glucocorticoid receptors (GR) in the locus ceruleus neurons of posttraumatic stress disorder(PTSD)like rats. Methods Sixty adult healthy male Wistar rats were enrolled in the experiment. PTSD-like rat model was established by single prolonged stress (SPS). There was no SPS stimulation in the control group and the rats of the other five groups were undisturbedly raised for 24 hours, 4 days,7 days,14 days and 28 days respectively after SPS stimulation.The expressions of glucocorticoid receptors in the locus ceruleus nucleus of all groups were detected with Nissl staining, immunohistochemistry,Western blotting and PCR, and image analysis and statistical analysis were performed. Results GR was distributed in the nucleus of coeruleus neurons, GR expression was showed after 24 hours, 4 days, 7 days treatment and gradually increased, restorative downregulation was seen after 14 days and 28 days, but still high(P<0.05). Conclusion After SPS, the GR locus ceruleus temporarily increased and then lowered, suggesting that PTSD rat locus coeruleus neurons in nuclear receptor-GR expression changes may directly involve in the continuing spirit of PTSD symptoms occurred in the development process.
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Objective To observe the effect of Fuzhenghunao capsule on NE of the locus ceruleus and myocardial tissues in rats with intracerebral hemorrhage. Methods 72 rats were randomly divided into 4 groups:sham,model,Fuzhenghunao and Angongniuhuang. The content of NE were tested by the high performance liquid phase-electrochemical method at 6 h,24 h and 72 h of post-operation. Result NE was obviously increased in sham group,and decreased in two treatment groups. Conclusion Fuzhenghunao capsule could be used to inhibit the activation of locus ceruleus noradrenalin system and protect myocardial tissues by regulating NE content.
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BACKGROUND AND OBJECTIVES: Subjective tinnitus, a distracting internal noise, is experienced by humans. Tinnitus is evoked by salicylic acid treatment in rats as confirmed by Jastreboff in 1994 in an animal behavior model of tinnitus with salicylic acid. The objective of this study is to evaluate c-fos expression in the brain stem of rats after salicylic acid treatment. MATERIALS AND METHOD: After salicylic acid (450 mg/kg) and saline treatment (450 mg/kg), c-fos immunohistochemical staining expression in the auditory and nonauditory brain stem nuclei were observed. RESULTS: Many immunoreactive cells were observed in the Locus Ceruleus of the salicylic acid treated animals, but not in the saline treated animals. No immunoreactive cells were found in the auditory brain stem nuclei. CONCLUSION: The Locus Ceruleus is the nucleus of the brain stem and produce norepinephrine which results in arousal of the neuronal activity for stress. These results suggest that salicylic acid may evoke tinnitus through a combined effect on the auditory and nonauditory brain nuclei. It seems possible that the interaction of these effects at particular locations of the brain causes tinnitus.
Subject(s)
Animals , Humans , Rats , Arousal , Behavior, Animal , Brain Stem , Brain , Locus Coeruleus , Neurons , Noise , Norepinephrine , Salicylic Acid , TinnitusABSTRACT
The neurotoxic effects of inorganic lead, a common environmental toxic substance, include peripheral neuropathy in adults and encephalopathy in children. Behavioral changes including hyperactivity, short attention span, easy distractibility and impulsiveness have also been noted in patients with chronic lead exposure in childhood. The level of norepinephrine in brain may relate to hyperactivity and chronic lead exposure. The purpose of this study was to determine the effect of inorganic lead (PbCl(2)) administration in neonatal rats using immunocytochemical and electron microscopical analysis of norepinephrinergic neurons of the locus ceruleus. Lead chloride were dissolved in distilled water at the concentration of 0.05%, 0.1% and 0.2% and the solution was administered orally via drinking water. After 4, 8 or 12 weeks of continuous administration, all rats were sacrificed and the brain was processed and immunostained with antibody against tyrosine hydroxylase, a rate limiting enzyme of norepinephrine synthesis antibody. The number of tyrosine hydroxylase immunostained cell bodies in locus ceruleus was estimated. Densitometric analysis of tyrosine hydroxylase immunoreactive profiles in electron microscopic photographs were done by using image analyzer. The number of tyrosine hydroxylase immunoreactive neurons in the locus ceruleus had increased statistically after lead administration. Density of tyrosine hydroxylase immunoreactive profiles in the electron microscopy had also increased. Degenerative changes, such as intra-axonal vacuolar space formation, were found within tyrosine hydroxylase immunoreactive axons. Somewhat widened intercellular spaces and retracted processes were also found in the region of the locus ceruleus. Increased tyrosine hydroxylase immunoreactivity may correlate with hyperreactivity of lead intoxicated children. Degenerative changes may be responsible for the short attention span, easy distractibility and impulsiveness observed in case of mild lead poisoning.
Subject(s)
Adult , Animals , Child , Humans , Rats , Axons , Brain , Drinking Water , Extracellular Space , Immunohistochemistry , Lead Poisoning , Locus Coeruleus , Microscopy, Electron , Neurons , Norepinephrine , Peripheral Nervous System Diseases , Tyrosine 3-Monooxygenase , WaterABSTRACT
[Objective] To investigate the influence of injection of substance P (SP) and its antagonist into locus ceruleus on electroacupuncture of Neiguan for acute myocardial ischemia (AMI). [Methods] Rabbit model of AMI was set up by ligating left ventricular branch of coronary artery. Forty-nine rabbits were allocated to five groups: Group A (the control group), Group B (electroacupuncture of Neiguan), Group C (injection of SP), Group D (electroacupuncture of Neiguan and injection of SP) and Group E (electroacupuncture of Neiguan and injection of SP antagonist) . Locus ceruleus was located by cerebral stereotaxic apparatus. Dynamic changes of ST segment of electrocardiogram and morphological feature of myocardium were observed. [ Results ] Injection of SP promoted the recovery of AMI and enhance the effect of electroacupuncture of Neiguan for AMI. However, the above effects were counteracted by the injection of SP antagonist. [Conclusion] SP plays an important role in reducing the damage of AMI on electroacupuncture of Neiguan and may serve as an important mediator for the connection of Neiguan and the heart.
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Although the distribution of locus ceruleus terminals has been demonstrated in the fundus striati[nucleus accumbens septi] by light microscopy[Jones & Moore, 1977 ; Mason & Fibiger, 1979 ; Streit or et al., 1979 ; Groenewegen et al., 1980], the synaptic organization of its terminals was not clarified. The purpose of the present investigation was to demonstrate the direct monosynaptic connection of the locus ceruleus terminals to the neuronal elements of the fundus stirati, and to clarify the synaptic structures of its terminals by electron microscopy two days after unilateral electric coagulation of the locus ceruleus. In the ipsilateral fundus striati, many axon terminals undergone dark degeneration were observed. These degenerating terminals containing small clear vesicles have asymmetric synaptic contacts with dendritic spines. Already two days after locus ceruleus lesion, distinct features of terminal degenerations appeared in the fundus striati ; enlarged axon terminals with altered synaptic vesicles, decrease of synaptic vesicles detached from the synaptic site, multiplication of dense bodies and infiltration of floccular material. At the same time, a regressive change occurred in which astrocytic processes encircled totally degenerated synapses spiraled around the synaptic remnants. These observations indicate that monosynaptic noradrenertic afferent connections to the fungus striati are confirmed, and the locus ceruleus terminals characterized by small round vesicles might be formed asymmetrical axo-spinous synapses with spiny neurons in the fundus striati.
Subject(s)
Animals , Cats , Dendritic Spines , Fungi , Locus Coeruleus , Microscopy, Electron , Neurons , Presynaptic Terminals , Synapses , Synaptic VesiclesABSTRACT
The microinjection of brain nuclei and potassium iontophresis induced tail flick were used to investigate the effect of injecting oxytocin (OT) or anti-oxytocin serum (AOTS) into locus ceruleus (LC) on the pain threshold (PT) and morphine analgesia. The result showed that OT injection into LC could enhance PT, while ATOS injection could reduce PT. The OT injection could strengthen morphine analgesia, but AOTS injection could antagonize this action. These results suggest that the OT analgesia and OT-enhanced morphine analgesia were related with the locus ceruleus.
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21 albino rats were used. The origin of the noradrenergic (NA) fibers in the septum was studied with a simultaneously combined retrograde fluorescent tracing and histofluorescence method. The results revealed that the NA neurons projecting to the septum were in A_1, A_2 and A_6 groups. The projections of A_1 were bilateral, But A_2 and A_6 projected dominantly to the ipsilateral septum, with a few to the contralateral. Retrograde labeled NA cells were localized in the rostrodorsal part of A_6 group, and scattered over the whole rostrocaudal length of A_(1,2) groups. No labeling was seen in A_4 and A_7 groups. In five of the animals, retrograde labeled NA cells were occasionally observed in A_5 group. In addition, some scattered labeled non-NA neurons were seen in the raphe and the ventrolateral reticular formation of the rostral medulla.