Regional Distribution of Neuropeptide Y and Its Receptor in the Porcine Central Nervous System

The regional distribution of neuropeptide Y (NPY) immunoreactivity and receptor binding was studied in the porcine CNS. The highest amounts of immunoreactive NPY were found in the hypothalamus, septum pellucidum, gyrus cinguli, cortex frontalis, parietalis, and piriformis, corpus amygdaloideum, and bulbus olfactorius (200-1,000 pmol/g wet weight). In the cortex temporalis and occipitalis, striatum, hippocampus, tractus olfactorius, corpus mamillare, thalamus, and globus pallidus, the NPY content was 50-200 pmol/g wet weight, whereas the striatum, colliculi, substantia nigra, cerebellum, pons, medulla oblongata, and medulla spinalis contained less than 50 pmol/g wet weight. The receptor binding of NPY was highest in the hippocampus, corpus fornicis, corpus amygdaloideum, nucleus accumbens, and neurohypophysis, with a range of 1.0-5.87 pmol/mg of protein. Intermediate binding (0.5-1.0 pmol/mg of protein) was found in the septum pellucidum, columna fornicis, corpus mamillare, cortex piriformis, gyrus cinguli, striatum, substantia grisea centralis, substantia nigra, and cerebellum. In the corpus callosum, basal ganglia, corpus pineale, colliculi, corpus geniculatum mediale, nucleus ruber, pons, medulla oblongata, and medulla spinalis, receptor binding of NPY was detectable but less than 0.5 pmol/mg of protein. No binding was observed in the bulbus and tractus olfactorius and adenohypophysis. In conclusion, immunoreactive NPY and its receptors are widespread in the porcine CNS, with predominant location in the limbic system, olfactory system, hypothalamoneurohypophysial tract, corpus striatum, and cerebral cortex.     

The Effect of Mesencephalic Lesions on Tyramine and Dopamine in the Caudate Nucleus of the Rat

Abstract: The dopamine (DA)-containing nerve terminals in the caudate nucleus arise from cell bodies located in the substantia nigra (pars compacta), and it is possible that p-tyramine- and m-tyramine-containing neurons may also exist in this nucleus. We have studied the effects of unilateral electrolytic lesions of the pars compacta in rat on levels of DA, p-tyramine, m-tyramine, and homovanillic acid in the caudate nucleus after various survival times. At 12 and 24 h following lesioning the ipsilateral level of p-tyramine was significantly reduced compared with the contralateral side, whereas the concentrations of m-tyramine, DA, and homovanillic acid were significantly increased. Thus, in the short term, the lesion results in an increase in DA turnover, which is accompanied by an increase in m-tyramine levels and a decrease in p-tyramine levels. Similar changes occur following pharmacological treatments (chlorpromazine, d-amphetamine, l-DOPA) that increase DA turnover. At survival times of 2, 11, and 25 days, the ipsilateral concentrations of m-tyramine, DA, and homovanillic acid were reduced along with p-tyramine. These longer-term alterations in amine levels are most likely a consequence of degeneration of nigro-striatal axons. Placement of a lesion 1 mm dorsal to the usual position centering on the pars compacta produced different biochemical changes from those seen after the pars compacta lesion. One day following this lesion the concentration of p-tyramine was slightly reduced; DA was unaffected, but the concentration of m-tyramine was profoundly increased, even more so than after the pars compacta lesion. This could indicate the existence of specific m-tyramine-containing cell bodies located dorsal to the substantia nigra. The results suggest that p- and m-tyramine in the caudate nucleus originate from neurons in or close to the substantia nigra. The results in the short term following the lesion support the observation that there is an inverse relationship between p-tyramine concentration and DA turnover in the caudate nucleus.     

3-Methoxytyramine Formation Following Monoamine Oxidase Inhibition Is a Poor Index of Dendritic Dopamine Release in the Substantia Nigra

Abstract: This study was undertaken, using microdialysis, to compare the extracellular concentration of 3-methoxytyramine and dopamine in dialysate from the striatum and substantia nigra, after pargyline (75 mg/kg), after pargyline plus amphetamine (3 mg/kg), and after pargyline plus reserpine (5 mg/kg) administration. Treatment with pargyline alone increased the extracellular dopamine concentration by 70% in the striatum and by 140% in the substantia nigra and induced in both regions a time-dependent accumulation of 3-methoxytyramine. The addition of d-amphetamine to pargyline increased the extracellular dopamine concentration, compared with pargyline-treated controls, to the same extent in both the substantia nigra (maximally by 360%) and the striatum (maximally by 400%), but the concomitant increase of 3-methoxytyramine accumulation in the dialysate was relatively smaller in the substantia nigra compared with the striatum. Reserpine treatment decreased the extracellular dopamine concentration in both regions below the detection level (<10% of basal value). When pargyline was added to reserpine, the striatal extracellular dopamine concentration increased to 50% of pargyline-treated controls and the striatal 3-methoxytyramine accumulation was less than in pargyline-treated controls. However, in the substantia nigra, the addition of pargyline to reserpine resulted in dopamine concentrations as high as after pargyline only and the 3-methoxytyramine accumulation was not changed compared with pargyline-treated controls. In summary, our results indicate that dopamine in the substantia nigra is released from reserpine-sensitive storage sites and that pargyline-induced 3-methoxytyramine accumulation is a poor indicator of the local dopamine release. The latter observation may be explained by the fact that the dopamine-metabolizing enzyme, catechol-O-methyltransferase, is located inter alia in the dopamine-containing cell bodies/dendrites in the substantia nigra, in contrast to the situation in the terminals in the striatum where catechol-O-methyltransferase is located only in nondopaminergic cells.     

Manganese accumulates in iron-deficient rat brain regions in a heterogeneous fashion and is associated with neurochemical alterations

Previous studies have shown that iron deficiency (ID) increases brain manganese (Mn), but specific regional changes have not been addressed. Weanling rats were fed one of three semipurified diets: control (CN), iron deficient (ID), or iron deficient/manganese fortified (IDMn+). Seven brain regions were analyzed for Mn concentration and amino acid (glutamate, glutamine, taurine, γ-aminobutyric acid) concentrations. Both ID and IDMn+ diets caused significant (p<0.05) increases in Mn concentration across brain regions compared to CN. The hippocampus was the only brain region in which the IDMn+ group accumulated significantly more Mn than both the CN and ID groups. ID significantly decreased GABA concentration in hippocampus, caudate putamen, and globus pallidus compared to CN rats. Taurine was significantly increased in the substantia nigra of the IDMn+ group compared to both ID and CN. ID also altered glutamate and glutamine concentrations in cortex, caudate putamen, and thalamus compared to CN. In the substantia nigra, Mn concentration positively correlated with increased taurine concentration, whereas in caudate putamen, Mn concentration negatively correlated with decreased GABA. These data show that ID is a significant risk factor for central nervous system Mn accumulation and that some of the neurochemical alterations associated with ID are specifically attributable to Mn accumulation.     

Evaluation of Markers of Oxidative Stress,Antioxidant Function and Astrocytic Proliferation in the Striatum and Frontal Cortex of Parkinson’s Disease Brains

Dopaminergic neurons die in Parkinson’s disease (PD) due to oxidative stress and mitochondrial dysfunction in the substantia nigra (SN). We evaluated if oxidative stress occurs in other brain regions like the caudate nucleus (CD), putamen (Put) and frontal cortex (FC) in human postmortem PD brains (n = 6). While protein oxidation was elevated only in CD (P < 0.05), lipid peroxidation was increased only in FC (P < 0.05) and protein nitration was unchanged in PD compared to controls. Interestingly, mitochondrial complex I (CI) activity was unaffected in PD compared to controls. There was a 3–5 fold increase in the total glutathione (GSH) levels in the three regions (P < 0.01 in FC and CD; P < 0.05 in Put) but activities of antioxidant enzymes catalase, superoxide dismutase, glutathione reductase and glutathione-s-tranferase were not increased. Total GSH levels were elevated in these areas because of decreased activity of gamma glutamyl transpeptidase (γ-GT) (P < 0.05) activity suggesting a decreased breakdown of GSH. There was an increase in expression of glial fibrillary acidic protein (GFAP) (P < 0.001 in FC; P < 0.05 in CD) and glutathione peroxidase (P < 0.05 in CD and Put) activity due to proliferation of astrocytes. We suggest that increased GSH and astrocytic proliferation protects non-SN brain regions from oxidative and mitochondrial damage in PD.     

Morphofunctional interaction of CART peptide and dopaminergic brain neurons

In Wistar rats, after 6 h of sleep deprivation and subsequent 2 h postdeprivation sleep, we found significant changes in optical density of CART peptide in neurons of nucleus accumbens and hypothalamic nucleus arcuatus as well as in processes coming into substantia nigra from nucleus accumbens. The obtained data revealed unidirectional changes of optical density of CART and tyrosine hydroxylase in the studied structures: a decrease after sleep deprivation (p < 0.05) and, on the contrary, an increase after postdeprivation sleep (p < 0.05). Confocal laser microscopy showed morphological connections of CART and dopaminergic neurons and possible colocalization of these both substances in the same neuron at the postdeprivation sleep. In experiments in vitro, after 1 h of incubation of surviving brain sections from the substantia nigra area in the medium with CART peptide there was revealed a rise of optical density of tyrosine hydroxylase in the substantia nigra pars compacta by 55% (p < 0.05). The obtained data indicate an activating effect of CART peptide on brain dopaminergic neurons and its role as a modulator of their functional activity.     

Experimental Parkinson's disease in monkeys. Effect of ergot alkaloid derivative on lipid peroxidation in different brain areas

The effects of the Parkinsonism induced by the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) were evaluated in four different monkey brain areas (frontal and occipital cortex, caudate putamen, substantia nigra). The basal and stimulated lipid peroxidation and the reduced glutathione (GSH) concentration were evaluated in three groups of maleMacaca fascicularis monkeys (6 animals/group): (a) controls; (b) MPTP-treated animals; (c) animals treated with MPTP and -dihydroergocryptine (DEK; ergot alkaloid characterized by a dopaminergic agonist action). In MPTP-treated animals the GSH concentration was unchanged or decreased in a non-significant way in the frontal and occipital cortex, and in substantia nigra. The basal thiobabituric acid reactive substance (TBARS) concentrations were significantly higher in the caudate putamen and substantia nigra of MPTP-treated animals. In the MPTP-treated monkeys the DEK administration induced a restoration of basal TBARS values to nearly normal ones. By incubating tissue from different brain areas with FeSO₄ plus ascorbic acid, the stimulation of lipid peroxidation decreased the TBARS production in the substantia nigra of the MPTP-treated animals. These results, taken together, may indicate that an increased lipid peroxidation could possibly play a role in producing the Parkinson-line syndrome by MPTP and that a free radical excess could be responsible for the degeneration of the substantia nigra. The treatment with an ergot alkaloid (i.e., -dihydroergocryptine) partially antagonizes the MPTP-induced increase in basal TBARS concentration in caudate putamen.     

Tremor following intracerebral carbachol injection. 1.Carbachol sensitivity of various brain structures]

Tremor produced by intracerebral injection of carbachol. I. Susceptibility of different brain areas to carbachol Microinjections of carbachol into the lateral ventricle of rats caused tremor depending on dose. Intensity and duration of motor effects after injection of carbachol (30 mug/3 mul bilateral) into different brain areas were found to depend on localization: strongest tremor was elicited by injections into the nucleus caudatoputamen and cortex cerebri, moderate tremor by administration into the substantia nigra reticularis, globus pallidus and thalamic brain regions. Target areas of mean sensitivity were demonstrated in more rostral and caudal parts of the formatio reticularis. The injection of carbachol into the nucleus ruber, nucleus linearis and substantia nigra compacta brought about lowest tremor values. Ablation of the site of injection from the remaining brain abolished tremor induced by carbachol contrary to the tremor induced by oxotremorine.     

Subcellular distribution of dopamine in substantia nigra of the rat brain: effects of gamma-butyrolactone and destruction of noradrenergic afferents suggest formation of particles from dendrites.

Abstract— The subcellular distribution of dopamine (DA) in substantia nigra from individual male rats was studied with a fractionation procedure on microscale. After differential centrifugation the distribution of DA coincided with that of noradrenaline (NA) which can serve as a marker for synaptosomes in this area. The proportion of DA/NA concentrations was about 1–2 in most fractions. Sixty per cent of nigral DA was found in P₂ (17,000 g). When P, was layered on a continuous density gradient, DA and NA peaked at the density of 1.0–1.2 M-sucrose. Since DA-containing particles covered a relatively broad range on this gradient, particles between 0.7 and 1.3 M-sucrose were collected with a discontinuous density gradient. Sixty per cent of DA from P₂, was found in this subfraction. The particles containing DA could have been derived from dendrites or axon collaterals of nigrostriatal neurones or represent precursor DA in noradrenergic (NA) terminals. The role of collaterals was investigated by comparing the effect of γ-butyrolactone (GBL, 750 mg/kg, 1 h) on DA concentrations in subcellular fractions from substantia nigra and caudate-putamen. In caudate-putamen, GBL produced a marked increase of DA in total homogenates and subcellular fractions except P₃, whereas DA concentrations remained unchanged in all fractions from substantia nigra. This speaks against a contribution from DA terminals. The proportion of DA contained as precursor in NA terminals was analysed after destruction of the NA input to substantia nigra by two methods. A single injection of 6-hydroxydopamine into the IV ventricle decreased nigral NA by 5574, DA only by 17%. Unilateral electrolytic lesions in the pontine tegmentum affected NA concentrations in homogenates and fraction P₂ of the ipsilateral substantia nigra to a much greater extent than DA. From the results obtained with the two approaches, it is estimated that precursor DA in particulate fractions does not exceed 10%. Our observations indicate that dendrites of the DA neurones in substantia nigra can form particles which behave like synaptosomes on density gradients centrifugation; they may be termed ‘dendrosomes’. According to the proportion of DA found in the particulate fractions at least 4040% of nigral DA appear to be localised in dendrites.     

Glucose uptake in mouse brain regions under hypoxic hypoxia

Glucose uptake of individual structures within the brain was studied by dry-autoradiography with 2-deoxy-D-[¹⁴C(U)]glucose under mild hypoxic hypoxia (12% O₂88% N₂ or 9% O₂91% N₂ for 1 hr). Glucose consumption in the whole brain was estimated by combined gas chromatography-mass spectrometry (GC-MS). Mild hypoxia increased the optical density of the autoradiograph in all regions. The deuterated G-6-P (Glucose-6-phosphate) synthesized from deuterated glucose decreased significantly with 9% O₂ hypoxia (P<0.05). The ratio of the deuterated G-6-P to deuterated glucose, a more appropriate indicator of glucose utilization than the concentration of deuterated G-6-P, decreased significantly with 12% O₂ hypoxia (P<0.01). The hippocampus, white matter, colliculus superior, and corpus geniculatum laterale appeared to be particulary sensitive to hypoxia.     

Distribution of NT-IR perikarya in the brain of the guinea pig with special reference to cardiovascular centers in the medulla oblongata

Summary The occurrence and distribution of neurotensin-immunoreactive (NT-IR) perikarya was studied in the central nervous system of the guinea pig using a newly raised antibody (KN 1). Numerous NT-IR perikarya were found in the nuclei amygdaloidei, nuclei septi interventriculare, hypothalamus, nucleus parafascicularis thalami, substantia grisea centralis mesencephali, ventral medulla oblongata, nucleus solitarius and spinal cord. The distribution of NT-IR perikarya was similar to that previously described in the rat and monkey. In the gyrus cinguli, hippocampus and nucleus olfactorius, though, no NT-IR neurons were detected in this investigation. Additional immunoreactive perikarya, however, were observed in areas of the ventral medulla oblongata, namely in the nucleus paragigantocellularis, nucleus retrofacialis and nucleus raphe obscurus.The relevance of the NT-IR perikarya within the ventral medulla oblongata is discussed with respect to other neuropeptides, which are found in this area, and to cardiovascular regulation.Abbreviations abl nucleus amygdaloideus basalis lateralis - abm nucleus amygdaloideus basalis medialis - acc nucleus amygdaloideus centralis - aco nucleus amygdaloideus corticalis - ahp area posterior hypothalami - ala nucleus amygdaloideus lateralis anterior - alp nucleus amygdaloideus lateralis posterior - ame nucleus amygdaloideus medialis - atv area tegmentalis ventralis - bst nucleus proprius striae terminalis - CA commissura anterior - CC corpus callosum - cgld corpus geniculatum laterale dorsale - cglv corpus geniculatum laterale ventrale - cgm corpus geniculatum mediale - CHO chiasma opticum - CI capsula interna - co nucleus commissuralis - cod nucleus cochlearis dorsalis - cp nucleus caudatus/Putamen - cs colliculus superior - cu nucleus cuneatus - dmh nucleus dorsomedialis hypothalami - DP decussatio pyramidum - em eminentia mediana - ent cortex entorhinalis - epi epiphysis - FLM fasciculus longitudinalis medialis - fm nucleus paraventricularis hypothalami pars filiformis - FX fornix - gd gyrus dentatus - gp globus pallidus - gr nucleus gracilis - hl nucleus habenulae lateralis - hm nucleus habenulae medialis - hpe hippocampus - ift nucleus infratrigeminalis - io oliva inferior - ip nucleus interpeduncularis - LM lemniscus medialis - MT tractus mamillo-thalamicus - na nucleus arcuatus - nls nucleus lateralis septi - nms nucleus medialis septi - npca nucleus proprius commissurae anterioris - ns nucleus solitarius - n III nucleus nervi oculomotorii - nt V nucleus tractus spinalis nervi trigemini - ntm nucleus mesencephalicus nervi trigemini - osc organum subcommissurale - P tractus cortico-spinalis - PC pedunculus cerebri - PCI pedunculus cerebellaris inferior - pir cortex piriformis - pol area praeoptica lateralis - pom area praeoptica medialis - prt area praetectalis - pt nucleus parataenialis - pvh nucleus paraventricularis hypothalami - pvt nucleus paraventricularis thalami - r nucleus ruber - re nucleus reuniens - rgi nucleus reticularis gigantocellularis - rl nucleus reticularis lateralis - rm nucleus raphe magnus - ro nucleus raphe obscurus - rp nucleus raphe pallidus - rpc nucleus reticularis parvocellularis - rpgc nucleus reticularis paragigantocellularis - sch nucleus suprachiasmaticus - SM stria medullaris thalami - snc substantia nigra compacta - snl substantia nigra lateralis - snr substantia nigra reticularis - ST stria terminalis - tad nucleus anterior dorsalis thalami - tam nucleus anterior medialis thalami - tav nucleus anterior ventralis thalami - tbl nucleus tuberolateralis - tc nucleus centralis thalami - tl nucleus lateralis thalami - tmd nucleus medialis dorsalis thalami - TO tractus opticus - TOL tractus olfactorium lateralis - tpo nucleus posterior thalami - tr nucleus reticularis thalami - trs nucleus triangularis septi - TS tractus solitarius - TS V tractus spinalis nervi trigemini - tvl nucleus ventrolateralis thalami - vmh nucleus ventromedialis hypothalami - vh ventral horn, Columna anterior - zi zona incerta Supported by the Deutsche Forschungsgesellschaft (DFG) SFB 90, Carvas     

Effects of castration on aggression and levels of serum sex hormones and their central receptors in mandarin voles (Microtus mandarinus)

Aggression in socially monogamous mandarin vole (Microtus mandarinus) was observed after castration. Levels of serum sex hormones and their central receptors were also measured using enzyme-linked immunosorbent assay and immunohistochemistry methods. The data indicate that adult males showed higher levels of aggression after castration. However, castration significantly reduced levels of serum testosterone, and the number of androgen receptor immunoreactive neurons in the anterior hypothalamus, bed nucleus of the stria terminalis, medial amygdaloid nucleus (P < 0.01) and lateral septal nucleus (P < 0.05). In addition, levels of estrogen receptor β in the anterior hypothalamus and medial amygdaloid nucleus (P < 0.05), bed nucleus of the stria terminalis and lateral septal nucleus (P < 0.01) declined to varying degrees at weekly intervals. In contrast, serum 17β-estradiol concentrations were up-regulated by castration and castration did not change levels of estrogen receptor α in the medial amygdaloid nucleus and lateral septal nucleus, but increased it in the anterior hypothalamus 3 weeks after castration (P < 0.05). We suggest that higher levels of aggression induced by castration may be independent of serum testosterone and androgen receptors, and may be associated with high serum 17β-estradiol concentrations, stable estrogen receptor α immunoreactive neurons in some brain regions and the relative ratio of the two estrogen receptors.     

Interplay between aggression,brain monoamines and fur color mutation in the American mink

Domestication of wild animals alters the aggression towards humans, brain monoamines and coat pigmentation. Our aim is the interplay between aggression, brain monoamines and depigmentation. The Hedlund white mutation in the American mink is an extreme case of depigmentation observed in domesticated animals. The aggressive (?2.06 ± 0.03) and tame (+3.5 ± 0.1) populations of wild‐type dark brown color (standard) minks were bred during 17 successive generations for aggressive or tame reaction towards humans, respectively. The Hedlund mutation was transferred to the aggressive and tame backgrounds to generate aggressive (?1.2 ± 0.1) and tame (+3.0 ± 0.2) Hedlund minks. Four groups of 10 males with equal expression of aggressive (?2) or tame (+5) behavior, standard or with the Hedlund mutation, were selected to study biogenic amines in the brain. Decreased levels of noradrenaline in the hypothalamus, but increased concentrations of the serotonin metabolite, 5‐hydroxyindoleacetic acid and dopamine metabolite, homovanillic acid, in the striatum were measured in the tame compared with the aggressive standard minks. The Hedlund mutation increased noradrenaline level in the hypothalamus and substantia nigra, serotonin level in the substantia nigra and striatum and decreased dopamine concentration in the hypothalamus and striatum. Significant interaction effects were found between the Hedlund mutation and aggressive behavior on serotonin metabolism in the substantia nigra (P < 0.001), dopamine level in the midbrain (P < 0.01) and its metabolism in the striatum (P < 0.05). These results provide the first experimental evidence of the interplay between aggression, brain monoamines and the Hedlund mutation in the American minks.     

Changes of Biogenic Amines and Their Metabolites in Postmortem Brains from Patients with Alzheimer-Type Dementia

Noradrenaline (NA), 3,4-dihydroxyphenylethylamine (dopamine, DA), 5-hydroxytryptamine (serotonin, 5-HT), homovanillic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA) were measured in 22 regions of postmortem brains from four histologically verified cases with Alzheimer-type dementia (ATD) and nine histologically normal controls. Compared with the controls, concentrations of 5-HT and 5-HIAA in the ATD brains were significantly reduced in nine regions (superior frontal gyrus, insula, cingulate gyrus, amygdala, putamen, medial and lateral segments of globus pallidus, substantia nigra, lateral nucleus of thalamus) and in eight regions (amygdala, substantia innominata, caudate, putamen, medial and lateral segments of globus pallidus, medial and lateral nuclei of thalamus), respectively. NA concentrations of the ATD brains were significantly reduced in six regions (cingulate gyrus, substantia innominata, putamen, hypothalamus, medial nucleus of thalamus, raphe area). In contrast, significant reductions of DA and HVA concentrations in the ATD brains were found only in putamen and amygdala, respectively. The 5-HIAA/5-HT ratio in the ATD brains decreased significantly in locus coeruleus, while the HVA/DA ratio increased significantly in putamen and medial segment of globus pallidus. These findings suggest that the serotonergic and noradrenergic systems are affected, while the dopaminergic system is relatively unaffected in ATD brains.     

Effect of glutaraldehyde fixation on the localization of various oxidative and hydrolytic enzymes in the brain of rhesus monkey, Macaca mulatta

Synopsis Histochemical investigations have been made on the localization of certain oxidative and hydrolytic enzymes in the different areas of rhesus monkey brain using unfixed, freshfrozen tissue and 3% glutaraldehyde-fixed material. After glutaraldehyde fixation, the oxidative enzymes lose most of their activity normally demonstrable in the fresh-frozen section. The hydrolytic enzymes are somewhat resistant to fixation but also lose about half of the enzyme activity observed after no fixing procedure. The glycogen is better preserved in the glutaraldehyde-fixed material compared to fresh-frozen or even formaldehyde-fixed tissue. The significance of these observations is discussed in relation to glutaraldehyde as a fixative of choice in electron histochemistry.List of abbreviations used in the Figures ALH area lateralis hypothalami - APH area posterior hypothalami - AS aquaeductus Sylvii - ATN anterior thalamic nuclei - BC brachium conjunctivum - CC corpus callosum - CD nucleus caudatus - CI capsula interna - CIS cortex insularis - CM centrum medianum thalami - COR corona radiata - CP commissura posterior - CSR colliculus superior - EM eminentia medialis - F fornix - GC substantia grisea centralis - GLM corpus geniculatum laterale, magnocellular part - GLP corpus geniculatum laterale, parvocellular part - GP globus pallidus - LD nucleus lateralis dorsalis thalami - LME lamina medullaris externa thalami - LMI lamina medullaris interna thalami - LP nucleus lateralis posterior thalami - MD nucleus medialis dorsalis thalami - ML nucleus lateralis corpus mammillaris - MM nucleus medialis corpus mammillaris - NC nucleus centralis thalami - NCI nucleus colliculi inferioris - NLL nucleus lemnisci lateralis - NR nucleus ruber - NSTH nucleus subthalamicus - N III nervus oculomotorius - PC nucleus paracentralis thalami - PCR pedunculus cerebri - PUT Putamen - PV nucleus paraventricularis hypothalami - R nucleus reticularis thalami - RU nucleus reuniens thalami - SM stria medullaris thalami - SMH nucleus supramammillaris hypothalami - SMT nucleus submedius thalami - SN substantia nigra - TO tractus opticus - VL nucleus ventralis lateralis thalami - VP nucleus ventralis posterior thalami - ZI zona incerta - II ventriculus lateralis - III ventriculus tertius     

Acupuncture protects from 6-OHDA-induced neuronal damage by balancing the ratio of DMT1/Fpn1

ObjectiveAcupuncture is a commonly used method to provide motor-symptomatic relief for patients with Parkinson s disease (PD). Our objective was to evaluate protective effects of acupuncture treatment and potential underlying mechanisms according to the “gut-brain axis” theory.MethodsWe employed a 6-OHDA-induced PD rat model. The effects of acupuncture on disease development were assessed by behavioural tests and immunohistochistry (IHC). ELISA, qPCR and western blot (WB) were employed to measure inflammatory parameters and Fe metabolism in the substantia nigra (SN), striatum, duodenum and blood, respectively.ResultsOur data show that acupuncture can significantly increase the expression of tyrosine hydroxylase (TH), compared with untreated and madopa treated rats (P < 0.01 and P < 0.05, respectively). Furthermore we could observe significantly decreased levels of pro-inflammatory markers in the duodenum and serum (P < 0.05), reduced deposition of Fe in the substantia nigra (P < 0.05) and but no change in transferrin expression after acupuncture treatment. The mRNA ratio of DMT1/Fpn1 in the SN of acupuncture treated rats (1.1) was comparable to that of the sham group (1.0) which differed both significantly from the untreated and madopa treated groups (P < 0.05). Furthermore, after acupuncture expression of α-synuclein was decreased in the duodenum.ConclusionsAcupuncture can reduce iron accumulation in the SN and protect the loss of dopamine neurons by promoting balanced expression of the iron importer DMT1 and the iron exporter Fpn1. Furthermore CNS iron homeostasis may be affected by reduced systemic and intestinal inflammation.     

Current concepts: II. Measurement of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid in discrete brain nuclei using reverse phase liquid chromatography with electrochemical detection

A rapid and sensitive method has been outlined for the measurement of 5-hydroxytryptamine (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) utilizing a weak cation-exchange resin and liquid chromatography with electrochemical detection. The sensitivity of the procedure allows measurement of the amine in punches of rat substantia nigra even after local injection of the neurotoxin 5,7-dihydroxytryptamine. Increases in 5-HT and decreases in 5-HIAA concentrations after pargyline, and selective increases in 5-HIAA concentrations after probenecid were detected in selected brain regions (nucleus accumbens, anterior striatum, substantia nigra). Thus, this procedure is sensitive enough to estimate 5-HT turnover in discrete nuclei of the rat brain.     

Release and Uptake Rates of 5-Hydroxytryptamine in the Dorsal Raphe and Substantia Nigra Reticulata of the Rat Brain

Abstract: Fast scan cyclic voltammetry with carbon fiber electrodes has been used to investigate the dynamics of the neurotransmitter 5-hydroxytryptamine (5-HT) in the extracellular fluid of two brain regions: the dorsal raphe and the substantia nigra reticulata. The method used previously was shown to be optimized to allow the time course of 5-HT concentration changes to be measured rapidly. Measurements were made in slices prepared from the brains of rats with the carbon fiber electrode inserted into the tissue and a bipolar stimulating electrode placed on the slice surface. Identification of 5-HT as the detected substance in both regions was based on voltammetric, anatomical, physiological, and pharmacological evidence. Autoradiography using [³H]paroxetine revealed highest 5-HT transporter binding densities in the regions in which voltammetric measurements were made. Evaluation of the pharmacological actions of tetrodotoxin and tetrabenazine, as well as the effects of calcium removal, suggested that 5-HT storage was vesicular and that the release process was exocytotic. The effects of fluoxetine (0.5 µM) were typical of a competitive uptake inhibitor, changing K_m with little effect on V_max. Release of 5-HT was found to be maximal with wide (2-ms) stimulus pulses in both regions, as expected for release from small unmyelinated processes, and to increase linearly with the number of pulses when high frequencies (100 Hz) were used. At lower frequencies, the concentration observed was a function of both release and uptake. Kinetic simulations of the data revealed that the major difference in 5-HT neurotransmission between the two regions was that release and uptake rates are twice as large in the dorsal raphe ([5-HT] per pulse = 100 ± 20 nM, V_max = 1,300 ± 20 nM/s for dorsal raphe; [5-HT] per pulse = 55 ± 7 nM, V_max = 570 ± 70 nM/s for substantia nigra reticulata). When normalized to tissue content, uptake rates in both regions were identical and similar to rates previously reported for dopamine in dopamine terminal regions. Nonetheless, compared with dopaminergic transmission in terminal regions such as the striatum, the absolute clearance rates in the substantia nigra reticulata and dorsal raphe were lower, resulting in a longer lifetime of 5-HT in the extracellular fluid and allowing long-range interactions.     

Afferent projections from the brainstem to the area hypothalamica dorsalis: a horseradish peroxidase study in the cat

Experiments using the retrograde transport of horseradish peroxidase were performed in order to identify the cells of origin the ascending projections from different brainstem regions to the area hypothalamica dorsalis (aHd) in the cat. The afferent inputs to this area originate mainly from the midbrain and medulla oblongata regions. The main afferent source of the area hypothalamica dorsalis arises from the substantia grisea centralis, where a large number of labeled cells were observed bilaterally, although more abundant on the ipsilateral side. Substantial afferents reach the aHd from the nuclei vestibularis medialis and inferior and the formatio reticularis mesencephali. A modest number of peroxidase-labeled neurons were observed in the nuclei ruber, interpeduncularis, substantia nigra, reticularis gigantocellularis, vestibularis lateralis, cuneatus and gracilis. From the pons, the nucleus raphe magnus sends a weak projection to the aHd. These anatomical data suggest that such area could be involved in visceral, sexual, nociceptive somatosensorial, sleep-waking and motor mechanisms.     

MPTP诱导的帕金森病小鼠模型黑质脑组织DNA甲基化研究

为研究DNA甲基化在帕金森病发病机制中的作用,本研究用环境毒素1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)连续腹腔给药诱导小鼠帕金森病(Parkison's disease,PD)模型,应用ELISA检测小鼠黑质脑组织总体甲基化水平,应用实时荧光定量PCR方法检测DNA甲基转移酶表达水平,探讨MPTP诱导的小鼠PD模型黑质部位是否存在DNA甲基化异常.进一步应用甲基化DNA免疫共沉淀结合DNA甲基化芯片方法,构建MPTP诱导的小鼠PD模型黑质脑组织DNA甲基化谱,并寻找DNA甲基化修饰异常的PD相关基因对其进行验证.结果表明,模型组小鼠黑质脑组织DNA总体甲基化水平较对照组显著降低,Dnmt1的表达水平显著增高.利用DNA甲基化芯片在全基因组内筛选出甲基化差异修饰位点共48个,涉及44个基因,这些甲基化差异基因参与信号转导、分子转运、转录调控、发育、细胞分化、凋亡调控、氧化应激、蛋白质降解等生物学过程.在甲基化差异修饰基因中,对Uchl1基因及Arih2基因进行了甲基化水平以及表达水平的验证.结果表明,模型组小鼠黑质脑组织Uchl1启动子区域甲基化水平较对照组增高,m RNA及蛋白质表达水平降低,Arih2启动子区域甲基化水平较对照组降低,m RNA及蛋白质表达水平增高.实验结果进一步证实,DNA甲基化修饰异常在帕金森病发病机制中有重要作用,环境因素(如MPTP)可以通过改变DNA甲基化修饰参与帕金森病的发生发展.