Dynamic changes of locus coeruleus damage in Parkinson's disease-like mice induced by paraquat / 中华劳动卫生职业病杂志

Objective: To observe the dynamic changes of brainstem locus coeruleus (LC) damage in Parkinson' s disease (PD) -like mice by paraquat (PQ) . Methods: In October 2019, 36 male C57BL/6 mice were randomly divided into the exposure group and the control group, with 18 mice in each group. The mice in the exposure group were given intraperitoneal injection of 15 mg/kg PQ, and the mice in the control group were given intraperitoneal injection of 0.9% saline, twice a week for 8 weeks. Neurobehavioral changes (pole climbing test, swimming test, open field test, tail hanging test, high plus maze test and water maze test) were observed at 4 weeks, 6 weeks and 8 weeks, respectively, and the changes of motor ability, emotion and cognitive function were evaluated. The brain tissue of mice were taken and stained with Hematoxylin-Eosin (HE) to observe the pathological changes of LC. Nissl staining was used to detect the changes of neuronal Nissl bodies in LC. Immunohistochemistry (IHC) staining was used to detect the expression of neuron nuclear antigen (NeuN) , dopamine (DA) neurons and norepinephrine (NE) neuron markers tyrosine hydroxylase (TH) , α-synuclein (α-syn) in substantia nigra (SN) and LC. The expression levels of NeuN, TH and α-syn in the midbrain and brainstem were detected by Western blotting. TUNEL staining was used to detect neuronal apoptosis in LC. Results: Compared with the 4th week of PQ exposure group, the time of pole climbing and swimming immobility were gradually increased, the ratio of open arm residence time of high plus maze test and the number of times of the platform and the residence time of platform quadrant in water maze test were gradually decreased (P<0.05) in the exposure group with the progress of exposure time. The results of HE and Nissl staining showed that the neurons in LC gradually arranged loosely, the nucleus were deeply stained, the cytoplasm was pyknosis, and the number of Nissl bodies gradually decreased (P<0.05) in the exposure group with the progress of exposure time. IHC results showed that the number of NeuN and TH positive cells in SN and LC of mice were gradually decreased, and the positive expression of α-syn was gradually increased (P<0.05) in the exposure group with the progress of exposure time. Western blotting results showed that the expression levels of NeuN and TH in the midbrain and brainstem were gradually decreased, and the expression level of α-syn was gradually increased (P<0.05) in the exposure group with the progress of exposure time. TUNEL staining showed that the apoptosis rates of neurons in LC were gradually increased (P<0.05) in the exposure group with the progress of exposure time. Conclusion: PQ induces progressive damage in the LC area of PD-like mice, which may be caused by the abnormal accumulation of pathological α-syn in the LC area.

Bone-edge electroacupuncture relieves pain by regulating expression of GRK5, β-arrestin 2 and PKCα proteins in locus coeruleus in bone cancer pain rats with morphine tolerance / 针刺研究

OBJECTIVE: To observe the effect of bone-edge electroacupuncture (EA) intervention on mechanical pain threshold (PT) and expression of G protein-coupled receptor kinase (GRK5), β-arrestin 2, total and phosphorylated PKC alpha (p-PKCα) proteins in the locus coeruleus (LC) of rats with bone cancer pain induced morphine tolerance, so as to reveal its partial central mechanisms underlying pain relief. METHODS: Forty SD rats were randomly divided into 5 groups, namely sham bone cancer, bone cancer pain, morphine tolerance, bone-edge EA, and sham EA (n＝ 8 rats in each group). The bone cancer with morphine tolerance model was established by intramedullary injection of MRMT-1 cells into the tibial cavity, and then intraperitoneal injection of morphine hydrochloride injection. After successful establishment of morphine tolerance model, the bone-edge EA (2 Hz/100 Hz，0.5－1.5 mA) was applied to bilateral "Zusanli" (ST36) and "Kunlun" (BL60) for 30 min, once a day for 7 days, after inserting the needle-tip to the tibial bone surface. The ipsilateral mechanical paw withdrawal thresholds (PWTs) were detected dynamically. The expression levels of GRK5, β-arrestin 2, PKCα and p-PKCα in the LC area were measured by Western blot. RESULTS: The PWTs of bone cancer pain rats were decreased on day 10 after inoculation of cancer cells (P0.05). The PWTs were significantly increased in the bone-edge EA intervention group (P0.05). In comparison with the sham bone cancer group, the expression of GRK5 protein in morphine tolerance group was significantly decreased (P<0.01); compared with morphine tolerance group, the expression of GRK5 protein in bone-edge EA group was increased(P<0.01). In comparison with the sham bone cancer group, the expression of β-arrestin 2 and p-PKCα in bone cancer group significantly increased (P<0.01). After the intervention, the increased β-arrestin 2 and p-PKCα expressions were reversed in the bone-edge EA group (P<0.01); compared with morphine tolerance group and sham EA group, the expression of PKCα protein was decreased(P<0.01). CONCLUSION: Bone-edge EA can effectively relieve morphine tolerance in bone cancer pain rats, which may be related to its functions in up-regulating GRK5 protein and down-regulating β-arrestin 2, PKCα and p-PKCα proteins in LC.　.

Effects of chronic stress caused by occlusal disorder on the body / 口腔疾病防治

@#Occlusal disorder is an abnormal condition in which the static and dynamic relations between the upper and lower teeth are not well aligned . The most common occlusal disorder in clinical practice is the inability to reach the intercuspal position due to early contact of individual points or occlusal interference due to occlusal high points, which can lead to periodontal tissue damage, decreased masticatory function, temporomandibular joint and muscle discomfort; these results can occur through the overactivation of the locus coeruleus-sympathetic-adrenal medullary system and hypothalamic-pituitary-adrenal axis induce elevated serum corticosteroid levels, which leads to chronic stress in the body. This article reviews the effects of chronic stress caused by occlusal disorder on bone tissue, stomatognathic system, emotional health and cognitive function. It has been found that occlusal disorders not only result in the loss of bone in the oral cavity, the reduction of bone mass in the whole body and damage to the local function of the stomatognathic system but also negatively affect the body’s anxiety, sleep, cognitive function and spatial memory ability as a result of the neuroendocrine changes . In recent years, concern about occlusal disorders has been on the rise. Early detection and timely adjustment of uncoordinated occlusion has become an issue that cannot be ignored in the clinic.

Electroacupuncture intervention relieves pain possibly by promoting MOR endocytosis in locus coeruleus in bone cancer pain rats with morphine tolerance / 针刺研究

OBJECTIVE: To observe the effect of electroacupuncture (EA) on pain behavior and expression of µ-opioid receptor (MOR) and Rab5 (an important protein molecule for internalization of MOR) in the locus coeruleus (LC) region in bone cancer pain (BCP) rats with morphine tolerance (MT), so as to explore its mechanisms underlying improvement of BCP and MT. METHODS: The present study included two parts. In the first part, 23 female SD rats were randomized into sham BCP (n＝6), BCP (n＝9) and BCP＋MT (n＝8) groups, and in the second part, 61 female SD rats were randomized into 5 groups: sham BCP (n＝11), BCP (n＝11), BCP＋MT (n＝13), BCP＋MT＋EA (n＝13) and BCP＋MT＋sham EA (n＝13). The BCP morphine tolerance (BCP＋MT) model was established by injection of 10 µL of human Walker 256 breast cancer cells (MRMT-1 breast cancer cells, 1 x104 cells/µL) into the bone marrow cavity at the upper part of the left tibia and intraperitoneal injection of morphine hydrochloride (10 mg/kg, once per 12 h, for 11 successive days). On day 21 after inoculation, EA (2 Hz/100 Hz, 0.5－1.5 mA, increasing 0.5 mA every 10 min) was began to applied to bilateral "Zusanli" (ST30) and "Kunlun" (BL60) immediately after the first intraperitoneal injection of morphine. The treatment was performed for 30 min every time, once daily for 7 successive days. The paw withdrawal threshold (PWT) was detected before and 10, 11, 21, 22, 24, 26 and 28 days after inoculation. The immunoactivity of MOR and Rab5 proteins in the LC region was detected by immunofluorescence histochemistry. RESULTS: In the first part of the study, at the 10th day after inoculation of cancer cells, the PWT of the BCP and BCP＋MT groups was significantly lower than that of the sham BCP group (P0.05) but significantly lower than that of the sham BCP group (P0.05). CONCLUSION: EA intervention can relieve pain and MT in bone cancer pain rats with MT, which may be related to its effects in increasing MOR expression and promoting endocytosis of MOR in LC region.

Quantification of Tyrosine Hydroxylase and ErbB4 in the Locus Coeruleus of Mood Disorder Patients Using a Multispectral Method to Prevent Interference with Immunocytochemical Signals by Neuromelanin / 神经科学通报·英文版

The locus coeruleus (LC) has been studied in major depressive disorder (MDD) and bipolar disorder (BD). A major problem of immunocytochemical studies in the human LC is interference with the staining of the immunocytochemical end-product by the omnipresent natural brown pigment neuromelanin. Here, we used a multispectral method to untangle the two colors: blue immunocytochemical staining and brown neuromelanin. We found significantly increased tyrosine hydroxylase (TH) in the LC of MDD patients-thus validating the method-but not in BD patients, and we did not find significant changes in the receptor tyrosine-protein kinase ErbB4 in the LC in MDD or BD patients. We observed clear co-localization of ErbB4, TH, and neuromelanin in the LC neurons. The different stress-related molecular changes in the LC may contribute to the different clinical symptoms in MDD and BD.

Effect of dexmedetomidine on visceral pain in rats: the role of a2 adrenergic receptors in locus coeruleus / 中华麻醉学杂志

Objective To evaluate the effect of dexmedetomidine on visceral pain in rats and the role of α2 adrenergic receptors in locus coeruleus (LC).Methods Thirty-two healthy adult male SpragueDawley rats,weighing 250-300 g,were divided into 4 groups (n=8 each) using a random number table method:control group (group C),visceral pain group (group VP),dexmedetomidine group (group DEX) and α2-adrenergic receptor antagonist atipamezole group (group AP).α2-adrenergic receptor antagonist atipamezole 522 μg/kg was intramuscularly injected in group AP,and the equal volume of normal saline was given instead in C,VP and DEX groups.At 10 min after intramuscular injection,dexmedetomidine 10 μg/kg was injected via the tail vein in DEX and AP groups,and the equal volume of normal saline was given instead in C and VP groups.VP,DEX and AP groups received intraperitoneal injection of 0.9％ acetic acid 10 ml/kg to make the visceral pain model at 15 min after injection via the tail vein.The cumulative visceral pain score was recorded within 60 min after acetic acid injection.The number of c-fos positive cells in LC was detected by immunohistochemistry,and the content of norepinephrine (NA) in the spinal cord were detected by enzyme-linked immunosorbent assay at 2 h after acetic acid injection.Results Compared with group C,the cumulative visceral pain scores,the number of c-fos positive cells in LC and content of NA in the spinal cord were significantly increased in VP,DEX and AP groups (P＜0.05).Compared with group VP,the cumulative visceral pain scores,the number of c-fos positive cells in LC and content of NA in the spinal cord were significantly decreased in DEX and AP groups (P＜0.05).Compared with group DEX,the cumulative visceral pain scores,the number of c-fos positive cells in LC and content of NA in the spinal cord were significantly increased in group AP (P＜0.05).Conclusion Dexmedetomidine can alleviate visceral pain in rats,and the mechanism is partially related to activating α2 adrenergic receptors in LC.

Activation of locus coeruleus heme oxygenase-carbon monoxide pathway promoted an anxiolytic-like effect in rats

The heme oxygenase-carbon monoxide pathway has been shown to play an important role in many physiological processes and is capable of altering nociception modulation in the nervous system by stimulating soluble guanylate cyclase (sGC). In the central nervous system, the locus coeruleus (LC) is known to be a region that expresses the heme oxygenase enzyme (HO), which catalyzes the metabolism of heme to carbon monoxide (CO). Additionally, several lines of evidence have suggested that the LC can be involved in the modulation of emotional states such as fear and anxiety. The purpose of this investigation was to evaluate the activation of the heme oxygenase-carbon monoxide pathway in the LC in the modulation of anxiety by using the elevated plus maze test (EPM) and light-dark box test (LDB) in rats. Experiments were performed on adult male Wistar rats weighing 250-300 g (n=182). The results showed that the intra-LC microinjection of heme-lysinate (600 nmol), a substrate for the enzyme HO, increased the number of entries into the open arms and the percentage of time spent in open arms in the elevated plus maze test, indicating a decrease in anxiety. Additionally, in the LDB test, intra-LC administration of heme-lysinate promoted an increase on time spent in the light compartment of the box. The intracerebroventricular microinjection of guanylate cyclase, an sGC inhibitor followed by the intra-LC microinjection of the heme-lysinate blocked the anxiolytic-like reaction on the EPM test and LDB test. It can therefore be concluded that CO in the LC produced by the HO pathway and acting via cGMP plays an anxiolytic-like role in the LC of rats.

Effect and function mechanism of Galanin on neonatal rat locus coeruleus neurons / 中国生化药物杂志

Objective To explore the effect of galanin ( GAL) on locus coeruleus ( LC) neurons from neonatal rat and mechanism with its receptor GalR and potassium channel.Methods Brain slices from neonatal rats were prepared and the resting membrane potential and spontaneous action potential of LC neurons were recorded with whole cell patch-clamp configuration.GAL, AR-M1896 and potassium channel blockers were bath applied with different concentration.Results Bath application GAL induced hyperpolarization and inhibited firing rate of LC neurons.However, AR-M1896 ( a selective GalR2 agonist) did not induce significant effect on LC neurons, only at very high concentration(1μM) it induced slight hyperpolarization and reduced firing rate.The inhibitory effect of GAL was partially blocked by TEA ( an antagonist of voltage-dependent potassium channel) and significantly blocked by BaCl2(an antagonist of inward-rectifying potassium channels), while other potassium channels blockers such as Glybenclamide(ATP-sensitive potassium channel blocker),Charybdotoxin(large-conductance Ca2 +-activated K + channels blocker),Apamin(small-conductance Ca2 +-activated K +channels blocker) failed to block it.Conclusion GAL inhibits LC neurons from neonatal rats, mainly through GalR1.TEA-sensitive potassium channels and inward-rectifying potassium channels, but not ATP-sensitive potassium channel and calcium-activated potassium channel, are involved in this inhibition.

Effects of yohimbine on norepinephrine release by locus coeruleus in stressed rats / 中华行为医学与脑科学杂志

Objective To study the cellular and molecular modulation mechanisms of norepinephrine (NE) release in hypothalamus induced by electrical stimulation in locus coeruleus (LC) in the rat model of depression-like behavior.Methods The depression-like behavior model was established by combining separation and chronic unpredictable stress stimulations.After the model establishment,behavior tests were used to verify the success of modeling.NE release in the hypothalamus induced by electrical stimulation in LC was studied in real time and NE signal was recorded with carbon fiber electrode.The peak value,the time to peak and half-life period of NE signal in both group rats were measured and analysed.Results The bodyweight,score of open-field test,percentage of sucrose preference of model group rats ((263.9± 16.4) g,(19.4±7.9),(44.3± 10.8) ％) were significantly lower than those((314.3±24.3) g,(53.3± 19.0),(60.6± 13.3) ％) of control group(P＜0.01).The peak value of NE signal in the hypothalamus induced by electrical stimulation in locus coeruleus in depression-like behavior model rats((176.9±50.4) pA)was less than that((361.6±88.6) pA)in control group(P＜0.01),and the time to peak of NE signal was also shortened in depression-like behavior model group rats (P＜0.05).Intraperitoneal injection of yohimbine (3 mg/kg) potentiated electrical stimulation induced NE release in depression-like behavior model rats but not in control group.Conclusion The chronic unpredictable stresses attenuate the secretion of NE in the hypothalamus induced by electrical stimulation in LC in rats.Yohimbine,a presynaptic α2 receptor antagonist,increased NE release in hypothalamus in depression-like behavior model rats.These findings suggest that the LC projects functionally to the hypothalamus and the projection may contribute to the pathogenesis of depression.

The neurobiology of infant maternal odor learning

Infant rats must learn to identify their mother’s diet-dependent odor. Once learned, maternal odor controls pups’ approach to the mother, their social behavior and nipple attachment. Here we present a review of the research from four different laboratories, which suggests that neural and behavioral responses to the natural maternal odor and neonatal learned odors are similar. Together, these data indicate that pups have a unique learning circuit relying on the olfactory bulb for neural plasticity and on the hyperfunctioning noradrenergic locus coeruleus flooding the olfactory bulb with norepinephrine to support the neural changes. Another important factor making this system unique is the inability of the amygdala to become incorporated into the infant learning circuit. Thus, infant rats appear to be primed in early life to learn odors that will evoke approach responses supporting attachment to the caregiver.

Analysis of Electrophysiological Change in the Rat LC Nucleus after Salicylic Acid Treatment / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: The precise mechanism of salicylic acid induced tinnitus has not been clearly identified as yet in spite of wide range of studies undertaken. We looked for the electrophysiologic evidence that salicylic acid has effect on the Locus Coeruleus (LC) neurons in vitro. MATERIALS AND METHOD: In LC, we measured the neuronal firing rate and cell membrane property according to the concentration of salicylic acid with extracellular single unit recording and whole cell current clamp recording. RESULTS: The basal firing activity was increased in 15 of the 20 LC nuclei, which were treated with 0.3 mM salicylic acid. Both 1mM and 2 mM salicylic acid increased the basal firing rate of all except for one LC neuron (n=20). These neurons also showed recovery after washing. However, 5 mM salicylic acid induced cell death after the bursting response in all of the LC neurons (n=10)(Fig. 2). There were no specific changes in the whole cell current-clamp recording of the LC neurons during the period of drug treatment (Fig. 3). CONCLUSION: The dose dependent response pattern observed in the extracellular single unit recording and the fact that there were no specific changes in the whole-cell current-clamp recording following the salicylic acid treatment suggest that the salicylic acid induced intracellular change in the LC neuron is caused not by the direct ligand-receptor reaction but by the indirect 2nd messenger system.

Immunohistochemical expression of CREB_1 proteins in brain in acute or chronic morphine addiction and withdrawal in rats / 解放军医学杂志

Objective To investigate the changes in CREB_1 proteins in five brain regions of rats with morphine addiction and withdrawal with the technique of immunohistochemistry. Methods Thirty six adult male Sprague-Dawley rats were randomly divided into six groups (n=6 for each), i.e. acute morphine dependent group, acute abstinence group, acute control group, chronic morphine dependent group, chronic abstinence group and chronic control group. Animals in dependent groups and abstinence groups were administered with morphine by intraperitoneal injection till morphine dependent models were established. The rats in abstinence groups withdrawal syndromes were induced with naloxone 5mg/kg for 30min. The rats in control groups were injected with saline. All rats were sacrificed by decapitation. The coronal sections of discrete brain regions (hypothalamus, nucleus accumbens, prefrontal cortex, locus coeruleus, hippocampus) were obtained. The relative concentrations of CREB_1 protein were determined with immunohistochemistry. Results In acute morphine dependent and abstinence groups, CREB_1 protein decreased significantly compared with the acute control group in locus coeruleus (P0.05). Conclusion The morphine-induced CREB_1 protein changes may reflect differential G protein-cAMP-CREB signal transduction pathways in morphine dependent and abstinence rats.

Expression of Gi_2 proteins in brain regions of acute or chronic morphine dependent rats / 解放军医学杂志

Objective To investigate the changes in inhibitory guanine nucleotide binding protein Gi_2 in five brain regions of morphine addicted rats: ventral tegmental area, nucleus accumbens, prefrontal cortex, hippocampus and locus caeruleus. Methods 36 adult male SD rats were randomly divided into six groups (n=6): acute morphine dependent group, acute abstinence group, acute control group, chronic morphine dependent group, chronic abstinent group and chronic control group. Morphine dependent models were reproduced. Withdrawal syndrome was induced with naloxone 5mg/kg for 30min in rats of abstinence group. All rats were sacrificed by decapitation. Frozen sections of coronal plane of respective brain regions (ventral tegmental area, nucleus accumbens, prefrontal cortex, locus coeruleus, hippocampus) were prepared. The relative concentrations of Gi_2 protein were determined with immunohistochemical methods. Results Gi_2 proteins in acute morphine dependent group and acute abstinence group were significantly decreased compared with that of acute control group in nucleus accumbens (P

The Inhibition of Stress-Induced c-fos Expression by Superior Cervical Ganglion Block in Rat Brain / 대한마취과학회지

BACKGROUND: Using c-fos expression one of the immediate early gene, as a marker of altered neuronal response, we investigated the effect of superior cervical ganglion block (SCGB) exhibiting the same effect of SGB of human on the activity of several brain regions which are considered as located on autonomic neural pathway and neuroendocrine axis in rat. METHOD: The 48 Sprague-Dawley strain rats were divided into 4 groups, as saline/stress (control) group, SCGB/stress (tested) group, saline group, SCGB group. Superior cervical ganglion block was conducted in the SCGB/stress group and SCGB group while saline/stress and saline group were sham operated. After then restraint stress was imposed on the animals of SCGB/stress group and saline/stress group. And 2 hour after injection (saline, SCGB group) or restraint stress (saline/stress, SCGB/stress group), c-fos protein (Fos) was localized by immunocytochemistry. RESULTS: Much stronger Fos immunoreactivity was induced in the several brain region of control group rats compared to other three groups and the numbers of Fos positive cell count of tested group were significantly decreased in paraventricular hypothalamic nucleus (p<0.01), A5 (p<0.01), raphe pallidus (p<0.05), nucleus tractus solitaius (p<0.01) compared to control group. CONCLUSION: This study demonstrate that superior cervical ganglion block attenuates stress induced neuronal activities of paraventricular hypothalamic nucleus, A5, raphe pallidus, nucleus tractus solitarius.

Effects of ketamine on noradrenaline release from the locus coeruleus in rabbits / 中华麻醉学杂志

Objective To investigate the effect of ketamine on the release of norepinephrine(NE)fromlocus coeruleus in the brain of rabbits,trying to elucidate the central mechanism of cardio-vascular responseinduced by ketamine.Methods Nine healthy male New Zealand rabbits weighing 2.0-2.5 kg were used in thisstudy.A trocar(0.8 mm in diameter)was inserted into locus coeruleus using the stereotactic technique and fixed.Four days later push-pull perfusion of the brain was performed.37℃ artificial cerebrospinal fluid(aCSF)wasinfused through the trocar at 0.1 ml?min~(-1).A loading dose of ketamine 2 mg?kg~(-1) was given i.v.followed byketamine infusion at 50 ?g?kg~(-1)?min~(-1) for 20 min.The perfusate from locus coeruleus was collected before duringand after ketamine infusion every 20 min.The NE concentration of the perfusate was measured by high performanceliquid chromatography(HPLC).Results The NE concentration of perfusate from locus coeruleus increasedsignificantly after ketamine infusion from(16?3) pg～?l~(-1) to(32?4)pg??l~(-1) and returned to baseline level 20min after termination of ketamine infusion.Conclusion Ketamine increases the concentration of NE in locuscoeruleus.The increased NE release from locus coeruleus may explain the central mechanism of circulatoryexcitement induced by ketamine.

Effects of propofol on noradrenaline release from the locus coeruleus in rabbits / 中华麻醉学杂志

Objective To investigate the effects of propofol on the release of noradrenaline ( NE) from the locus coeruleus in the brain of rabbits trying to elucidate the central mechanism of the cardiovascular inhibition induced by propofol.Methods Nine healthy male New Zealand rabbits weighing 2.0-2.5 kg were used in this study. A trocar (0.8 mm in diameter) was inserted into locus coeruleus using the stereotactic technique and fixed. Four days later push-pull perfusion of the brain was performed. 37℃ artificial cerebrospinal fluid (aCSF) was infused through the trocar at 0.1 ml?min-1 . A loading dose of propofol 2 mg?kg-1 was given i.v. followed by continuous infusion at 150 ?g?kg-1?min-1 for 30 min. The experiment was concluded at 20 min after propofol infusion. The perfusate having passed through the locus coeruleus was collected before and every 10 min during and after infusion. The NE concentration of the perfusate was measured by high performance liquid chromatography. Results The NE concentration of the perfusate from locus coeruleus significantly decreased after the loading dose and during the infusion of propofol and reached its bottom level at 10 min after loading dose. The maximal decrease was 75.5% [from (15.9 ? 3.2) pg??l-1 to (3.9?0.5) pg ? ?l-1]. Conclusion Intravenous propofol decreases the NE concentration in locus coeruleus. The cardiovascular inhibition induced by propofol may partly be explained by this central mechanism.

Effect of clonidine on intraocular pressure and its central adrenergic mechanism / 中国药理学通报

AIM To investigate the effect of clonidine on intraocular pressure(IOP) and the possible role in which ? adrenergic mechanism plays. METHODS The change on IOP was observed following clonidine administered via three different routes: (1)clonidine topically administered to eyes; (2)clonidine intracerebroventricularly injected (icv)or topically administered after yohimbine or prazosin icv; (3)microinjection of clonidine into locus coeruleus(LC). RESULTS Clonidine decreased IOP significantly, ? 2 adrenoceptor antagonist, but not ? 1 adrenoceptor antagonist, can reverse the decreasing effect on IOP caused by clonidine icv and administered topically. CONCLUSION Clonidine administered both topically or intracranially can decrease IOP;? 2 adrenoceptor in central nervous system is involved in this effect.

AGING CHANGES IN TYROSINE HYDROXYLASE IMMUNOREATIVE NEURONS IN THE LOCUS COERULEUS OF THE RAT / 西安交通大学学报(医学版)

Aging changes of tyrosine hydroxylase (TH) -immuno reactive neurons in the locus coeruleus were examined in young (3 month-old). adult(12 month-old) and aged(20 month-old) Wistar male rats, using the IGSS method and image quantitative analysis. The results obtained are as follows: ① The number of TH-immunoreactive neurons docreased markedly (P

DIVERGENT AXON COLLATERALS FROM NEURONS IN LOCUS COERULEUS TO PREFRONTAL CORTEX, HIPPOCAMPUS, THALAMUS, CEREBELLUM AND SPINAL CORD OF RAT. A FLUORESCENT DOUBLE LABELINE STUDY / 解剖学报

The divergent axon collaterals from neurons in locus coeruleus have been in vestigated by means of fluorescent double labeling technique in 36 rats.Different fluorescent tracers, Fast Blue, Nuclear Yellow, Propidium iodide, Bisbenzimide, Evans Blue, DAPI and Primuline were injected into the prefrontal cortex, the thalamus, the hippocampus, the cerebellum and cervical cord to observe the double retrograde labeling neurons of the locus coeruleus.Following unilateral or bilateral combined injections of two fluorescent tracers into the thalamus and cerebellum, the hippocampus and cerebellum, the hippocampus and thalamus, the larefrontal cortex and cerebellum, the prefrontal cortex and thalamus, the prefrontal cortex and cervical cord, the hippocampus and cervical cord, the cerebellum and cervical cord, double labeled cells were found in locus coeruleus, and some topographical organizations were also found.