OBJECTIVETo observe the changes of mitochondria stress in locus coeruleus and the tyrosine hydroxylasic projection after long-term sleep deprivation.

METHODSSleep deprivation mice model was set up by employing "novel environments" method. The expression of NAD -dependent deacetylase Sirtuin type 3 (SIRT3), which regulates mitochondrial energy production and oxidative stress, and heat shock protein 60 (HSP60), a major biomarker of mitochondrial stress, and the tyrosine hydroxylasic projection from locus coeruleus were analyzed after a 5-day sleep deprivation.

RESULTSCompared to the control group, the expression of SIRT3 in locus coeruleus was significantly decreased in respouse to long-term sleep deprivation, while the expression of HSP60 was significantly increased. In addition, relative to control group, pereentage area of the tyrosine hydroxylasic projection to anterior cingulate cortex was substantial decreased in long-term sleep deprivation group.

CONCLUSIONLong-term sleep deprivation induced the decreased level of SIRT3 expression and the elevation of mitochondrial stress in locus coenileus, which may further lead to the loss of tyrosine hydroxylasic projection in mice.

Animals ; Chaperonin 60 ; metabolism ; Locus Coeruleus ; metabolism ; physiology ; Mice ; Mitochondria ; metabolism ; Mitochondrial Proteins ; metabolism ; Oxidative Stress ; physiology ; Sirtuin 3 ; metabolism ; Sleep Deprivation ; Tyrosine ; metabolism

Norepinephrine (NE)-containing locus ceruleus (LC) has been known to participate in the regulation of the sleep-wake cycle according to the differential firing rate. The aim of this study was to know the change of extracellular NE level in the rat amygdala, which are reciprocally connected with LC, during sleep-wake-fulness. Extracellular NE levels in the rat amygdala were inrestigated during different stages of the sleep-waking cycle using in vivo microdialysis and polygraphic recording. Dialysates were collected every 5 min and correlated with the results of polygraphic recording. The content of NE was measured by high-performance liquid chromatography with electrochemical detection. NE level was the highest in active waking (AW) and, when compared to AW, NE level was progressively lower in quiet waking (QW; 86%), quiet sleep (QS; 72%), and active sleep (AS or REM sleep; 61%). This result suggests that the rat amygdala also participates in the regulation of the sleep-wake cycle according to the differential NE release.
Amygdala/*metabolism ; Animals ; Arousal/*physiology ; Electroencephalography ; Extracellular Space/metabolism ; Locus Coeruleus/metabolism ; Male ; Microdialysis ; Norepinephrine/*metabolism ; Rats ; Rats, Sprague-Dawley ; Sleep/*physiology

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.
Animals ; Dopaminergic Neurons ; Locus Coeruleus/pathology* ; Male ; Mice ; Mice, Inbred C57BL ; Paraquat/toxicity* ; Parkinson Disease/metabolism* ; Substantia Nigra ; Tyrosine 3-Monooxygenase/metabolism*

OBJECTIVETo investigate the changes in the firing activity of noradrenergic neurons in the locus coeruleus (LC) in a rat model of Parkinson disease (PD).

METHODS2 and 4 weeks after unilateral lesion of the nigrostriatal pathway in the rat by local injection of 6-hydroxydopamine (6-OHDA) into the right substantia nigra pars compacta (SNc), the firing activity of noradrenergic neurons in LC was recorded by extracellular single unit recording.

RESULTSThe firing rate of LC noradrenergic neurons increased significantly 2 and 4 weeks after 6-OHDA lesions compared to normal rats, respectively (P < 0.05). The percentage of irregularly firing neurons was obviously higher than that of normal rats during the fourth week after SNc lesion (P < 0.05).

CONCLUSIONLC noradrenergic neurons are overactive and more irregular in 6-OHDA-lesioned rats. These changes suggest an implication of the LC in the pathophysiological mechanism of PD.

Action Potentials ; physiology ; Animals ; Disease Models, Animal ; Locus Coeruleus ; pathology ; Male ; Neurons ; physiology ; Norepinephrine ; metabolism ; Oxidopamine ; Parkinsonian Disorders ; chemically induced ; pathology ; Rats ; Rats, Sprague-Dawley ; Time Factors

It has been known that locus coeruleus (LC) stimulation suppresses nociceptive discharges of the thalamic parafascicular (PF) neurons through the spinally descending adrenergic terminals which inhibit the transmission of nociceptive signals in the spinal dorsal horn. This experimental model was used in the present study to analyze the detailed processes that happened in the dorsal horn following norepinephrine release by preemptive intrathecal (i.t.) administration of related drugs in lightly urethane-anesthetized rats. The results showed that: (1) LC stimulation significantly inhibited the noxiously-evoked discharges of PF neurons; (2) the LC stimulation-produced antinociception in PF neurons could be blocked either by i.t. glibenclamide, an ATP-sensitive potassium (K(+)(ATP)) channel blocker, or by i.t. aminophylline, an adenosine receptor antagonist; (3) nociceptive discharges of PF neurons were also suppressed both by i.t. 5 -N-ethylcarboxamido-adenosine (NECA, an adenosine receptor agonist) and by i.t. nicorandil (a K(+)(ATP) channel opener); and (4) i.t. aminophylline blocked the suppression of PF nociceptive discharges induced by i.t. nicorandil, while i.t. glibenclamide showed no effect on the suppression of nociceptive discharges induced by i.t. NECA. These results suggest that: (1) K(+)(ATP) channels and endogenous adenosine may be involved in the mediation of spinal antinociception induced by descending adrenergic fibers originating from the LC; and (2) the opening of K(+)(ATP) channels precedes the release of adenosine in the cascade of mediation.
Adenosine ; metabolism ; physiology ; Adenosine Triphosphate ; physiology ; Animals ; Electric Stimulation ; Female ; Injections, Spinal ; Locus Coeruleus ; physiology ; Male ; Pain ; physiopathology ; Potassium Channels ; physiology ; Rats ; Rats, Wistar

AIM AND METHODSIn the present study, we investigated the TH immunoreactivity and the expression of angiotensin AT1 receptor in locus coeruleus after intracerebroventricular (i. c. v.) injection of carbachol in conscious SD rats with immunohistochemistry. Meanwhile the effects of blocking AT1 receptor were also observed.

RESULTSBoth mean optical density and number of TH and AT1 immunoreactive positive neurons were markedly increased in locus coeruleus after 40 minutes of i.c.v. injection of carbachol (0.5 microg). The enhancement was significantly reduced by i. c. v. injection of losartan.

CONCLUSIONThe results above suggest that i. c. v. injection of cholinergic agonist carbachol can enhance the activity of adrenergic neurons and the expression of AT1 receptor in locus coeruleus. The blockade of AT1 receptor may down regulate the above action induced by carbachol in locus coeruleus.

Animals ; Brain ; Carbachol ; pharmacology ; Cholinergic Agents ; pharmacology ; Injections, Intraventricular ; Locus Coeruleus ; drug effects ; metabolism ; Losartan ; pharmacology ; Male ; Neurons ; metabolism ; Rats ; Rats, Sprague-Dawley ; Receptor, Angiotensin, Type 1 ; metabolism ; Tyrosine 3-Monooxygenase

AIMTo Investigate the effect of glutamate (Glu) and gamma-aminobutyric acid(GABA) in orbitofrontal cortex (OFC) on regulation of gastric motility.

METHODSUsing microinjection in OFC,together with lesion of related nucleus,and recording the intragastric pressure(IGP).

RESULTS(1) Microinjection of Glu in OFC caused a significant reduce of the amplitude of gastric motility, this effect could be reverse by lesion of amygdala, while lesion of LC had no influence on the effect of Glu. (2) microinjection of GABA in OFC could increase the amplitude of gastric motility significantly,and lesion of LC could abolish this effect,while lesion of amygdala could enhance the effect of GABA more.

CONCLUSIONMicroinjection of Glu in OFC may enhance the normal inhibitory effect of amygdale on gastric motility, and the effect of microinjection of GABA in OFC on gastric motility is closely related with LC.

Amygdala ; physiology ; Animals ; Female ; Frontal Lobe ; metabolism ; physiology ; Gastrointestinal Motility ; drug effects ; Glutamic Acid ; pharmacology ; Locus Coeruleus ; physiology ; Male ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; gamma-Aminobutyric Acid ; pharmacology

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.
Aged ; Aged, 80 and over ; Bipolar Disorder ; metabolism ; pathology ; Depressive Disorder, Major ; metabolism ; pathology ; Female ; Humans ; Image Processing, Computer-Assisted ; Immunohistochemistry ; methods ; Locus Coeruleus ; metabolism ; pathology ; Male ; Melanins ; metabolism ; Microscopy ; methods ; Middle Aged ; Neurons ; metabolism ; pathology ; Receptor, ErbB-4 ; metabolism ; Sensitivity and Specificity ; Spectrum Analysis ; methods ; Tyrosine 3-Monooxygenase ; metabolism

OBJECTIVE: This study investigates the effects of chronic alcohol exposure on rat brain THmRNA expression, TH (tyrosine hydroxylase) acitivity, and TPH (tryptophan hydroxylase) activity which are important in synthesis of dopamine and serotonin and other components of both the dopaminergic and serotonergic systems of the rat brain. METHODS: Rats were fed a liquid diet containing alcohol for 4 weeks. We investigated effects of chronic alcohol exposure on dopaminergic systems as follows. We evaluated expression of THmRNA in LC, VTA and substantia nigra by using in-situ hybridization and measured activity of TH by using immunoassay. We used HPLC for simultaneous measurement of dopamine, DOPAC and HVA in the cerebral cortex, striatum, hypothalamus, hippocampus, mid brain, hind brain, and cerebellum. Also we investigated serotonergic systems as follows. We evaluated expression of TH mRNA in the dorsal raphe nucleus by using radioprobe and measured the activity of TPH by using enzyme immunoassay. We used HPLC for simultaneous measurement of 5-HT and 5-HIAA in the cerebral cortex, striatum, hypothalamus, hippocampus, mid brain, hind brain, and cerebellum. RESULTS: Alcohol exposure for 4 weeks increased the expression of TH mRNA in the ventral tegmental area and the locus ceruleus but not in the substantia nigra. The 4 weeks of alcohol exposure did not cause significant changes in levels of dopamine and metabolites in the different areas of the brain, nor was it associated with changes in the maximal binding and affinity (Kd) of anterior striatal dopamine D2 receptor. Alcohol exposure for 4 weeks had no effect on the expression of TPH mRNA or on the activity of TPH in the dorsal raphe nucleus and the hypothalamus. CONCLUSION: We reported at first that chronic alcohol exposure could increase TH mRNA in the locus ceruleus. In a previous study of acute alcohol treatment, there is increase of dopamine metabolism but in this study, we did not observe any changes in dopamine metabolism in the different areas of the brain. Also we did not see any significant changes in the synthesis and metabolism of serotonin after 4 weeks of chronic alcohol exposure compared with control. Therefore, synthesis and metabolism of serotonin was affected in the acute phase. And, as previous reports have suggested, any changes caused by alcohol returned to previous levels via adaptation and regulatory mechanisms.
3,4-Dihydroxyphenylacetic Acid ; Animals ; Brain ; Cerebellum ; Cerebral Cortex ; Chromatography, High Pressure Liquid ; Diet ; Dopamine ; Hippocampus ; Hydroxyindoleacetic Acid ; Hypothalamus ; Immunoassay ; Immunoenzyme Techniques ; Locus Coeruleus ; Metabolism ; Raphe Nuclei ; Rats* ; Receptors, Dopamine D2 ; Rhombencephalon ; RNA, Messenger ; Serotonin ; Substantia Nigra ; Synaptic Transmission* ; Ventral Tegmental Area