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  • 1
    Electronic Resource
    Electronic Resource
    On the Origin of Striatal Cholecystokinin Release: Studies with In Vivo Microdialysis (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 62 (1994), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: In the present study, extracellular levels of the neuropeptide cholecystokinin (CCK), of the monoamine dopamine and its metabolites 3, 4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA), and of the excitatory amino acids glutamate and aspartate were simultaneously monitored by microdialysis in the neostriatum of halothane-anesthetized rats under basal and K+-depolarizing conditions. Extracellular CCK and dopamine levels, but not glutamate and aspartate levels, were decreased by perfusion with a Ca2+-free medium, under both basal and K+-depolarizing conditions. HPLC revealed that the majority of the CCK-like immunoreactivity in the perfusates coeluted with CCK octapeptide. Striatal extracellular CCK levels were decreased by decortication plus callosotomy, with a parallel decrease in glutamate levels. Striatal extracellular levels of dopamine, DOPAC., and HVA were significantly decreased in animals treated previously with a unilateral 6-hydroxydopamine injection into the medial forebrain bundle. In these animals, however, the effect of decortication plus callosotomy on CCK and glutamate levels was not further augmented. Thus, this study supports the hypothesis of a neuronal origin of extracellular CCK and dopamine monitored with microdialysis in the striatum of the rat, and also supports the idea of a partly contralateral origin of corticostriatal CCK and glutamate inputs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.1994.62010076.x
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  • 2
    Electronic Resource
    Electronic Resource
    CCK in Cerebral Cortex and at the Spinal Level (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 713 (1994), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1994.tb44062.x
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  • 3
    Electronic Resource
    Electronic Resource
    Tachykinins and Related Peptides in the Substantia Nigra and Neostriatum (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 632 (1991), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1991.tb33107.x
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  • 4
    Electronic Resource
    Electronic Resource
    Cholecystokinin in Cortico-striatal Neurons in the Rat: Immunohistochemical Studies at the Light and Electron Microscopical Level (1994)
    Oxford, UK : Blackwell Publishing Ltd
    European journal of neuroscience 6 (1994), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Using immunohistochemical techniques we have analysed the occurrence of cholecystokinin-like immunoreactivity (CCK-LI) in the cortex and striatum of the rat. In the cortex few CCK-immunoreactive cell bodies, mainly interneurons, could be visualized in normal brains, and a moderately dense network of CCK fibres was also observed. Injections of colchicine into the striatum led to an accumulation, in the surrounding cortex, of CCK-LI in the initial segment of the axon of numerous cells. In addition, with an antibody to pro-CCK several cell bodies, many of which with pyramidal shape, could be visualized. Furthermore, retrograde staining of cortical cells after unilateral injection of wheat germ agglutinin into the striatum revealed bilaterally in the cortex a number of labelled cells that also contained pro-CCK-LI. In the striatum CCK-LI was diffusely distributed in fine fibres as well as in patches of fibres located in the medial aspects. After decortication followed by callosotomy these patches disappeared on the side ipsilateral to the lesion, while the pattern of immunoreactivity of several other peptides in the striatum was unaffected. No change was observed on the contralateral side. Decortication or callosotomy alone did not affect the pattern of CCK-LI. At the ultrastructural level several CCK-immunoreactive terminals could be observed, mostly with clear, densely packed vesicles and straight asymmetric synaptic contacts with small spines, characteristic for terminals of cortical origin. The results are consistent with the presence of a major, partly crossed, CCK-containing cortico-striatal pathway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1460-9568.1994.tb00980.x
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  • 5
    Electronic Resource
    Electronic Resource
    Neuropeptide gene expression in brain is differentially regulated by midbrain dopamine neurons (1990)
    Springer
    Experimental brain research 80 (1990), S. 489-500 
    Details
    ISSN: 1432-1106
    Keywords: Dopamine ; Neuropeptide Y ; Somatostatin ; Tachykinin ; Cholecystokinin ; In situ hybridization ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In situ hybridization was used to study the expression of prepro-neuropeptide Y (NPY), preprosomatostatin (SOM), preprotachykinin (PPT) and preprocholecystokinin (CCK) mRNA in caudate-putamen and frontoparietal cortex of rat brain with unilateral lesion of midbrain dopamine neurons. Neurons expressing NPY and SOM mRNA showed a similar distribution and the expression of both NPY and SOM appears to be regulated by dopamine in a similar fashion. Following a dopamine deafferentation, the numerical density of both NPY and SOM mRNA producing neurons almost doubled in the lesioned caudate-putamen with no change in the average grain density over positive neurons. Hence, in the intact caudate-putamen dopamine appears to suppress expression of these two neuropeptide genes leading to an activation of both NPY and SOM mRNA expression in many non- or low-expressing neurons when the level of dopamine is decreased. In the fronto-parietal cortex, on the other hand, dopamine appears to stimulate NPY and SOM gene expression. Thus, in the absence of dopamine about half of the NPY positive neurons disappeared. However, for SOM the number of positive neurons did not change, but rather most positive neurons appeared to have down-regulated their SOM mRNA expression. No evidence was found for a change in CCK mRNA expression by the dopamine deafferentation, while PPT mRNA expression decreased in the deafferented caudate-putamen. Consequently, dopamine exerts dissimilar effects on the expression of different neuropeptide genes, that in turn do not respond in the same way in different brain regions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227990
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  • 6
    Electronic Resource
    Electronic Resource
    Striatonigral GABA, dynorphin, substance P and neurokinin A modulation of nigrostriatal dopamine release: evidence for direct regulatory mechanisms (1990)
    Springer
    Experimental brain research 82 (1990), S. 293-303 
    Details
    ISSN: 1432-1106
    Keywords: Dynorphin ; Substance P ; Neurokinin A ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The striatonigral pathway contains several neurotransmitters which may regulate the activity of the nigrostriatal dopamine projection in the rat. This was investigated by measuring extracellular dopamine levels in the striatum, using microdialysis, after injections of GABA (300 nmol/0.2 μl), dynorphin A (0.5 nmol/0.2 μl), substance P (0.07 mnol/0.2 μl) or neurokinin A (0.09 nmol/0.2 μl) into the ipsilateral substantia nigra, pars reticulata (SNR). Intranigral injections of GABA or dynorphin A inhibited, while intranigral injections of substance P or neurokinin A stimulated dopamine levels in the ipsilateral striatum. In rats with ibotenic acid lesions (2.5 μg/0.5 μl) in the SNR, intranigral injections of GABA or dynorphin A inhibited, while intranigral injections of substance P or neurokinin A stimulated dopamine levels in the ipsilateral striatum. These responses were not significantly different than those in unlesioned rats. Analysis of the intranigral lesion with in situ hybridization revealed a heavy loss of glutamic acid decarboxylase mRNA expression in the SNR and a significant loss of tyrosine hydroxylase (TH) mRNA expression in the SNC. Immunohistochemical analysis revealed a disappearance of TH-Like immunoreactivity (LI) im dendrites in the SNR, a considerable loss of TH-LI cell bodies in the SNC and a restricted loss of neuropeptide K-LI in the SNR around the tip of the injection cannula. Furthermore, lesioned rats rotated ipsilateral to the lesion after apomorphine (1 mg/kg, s.c.), indicating that the basal ganglia output mediated via the SNR GABA neurons was impaired on the lesioned side. Analysis of the striatum revealed that a dense TH-LI fiber network could still be seen on the lesioned side. Furthermore, basal and amphetamine stimulated extracellular dopamine levels in the striatum on the lesioned side were not significantly depleted. This indicates that the ascending nigrostriatal dopamine projection was functionally intact on the lesioned side. These findings indicate that intranigral GABA, dynorphin A, substance P and neurokinin A modulation of ipsilateral striatal dopamine release is mediated via direct action on the nigrostriatal projection. Thus, it is suggested that the striatonigral pathway, which contains GABA, dynorphin, substance P and neurokinin A, exerts a direct regulatory effect on the activity of the nigrostriatal dopamine projection.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00231249
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  • 7
    Electronic Resource
    Electronic Resource
    Expression of dopamine D2 receptor and choline acetyltransferase mRNA in the dopamine deafferented rat caudate-putamen (1990)
    Springer
    Experimental brain research 83 (1990), S. 96-104 
    Details
    ISSN: 1432-1106
    Keywords: Caudate-putamen ; 6-hydroxydopamine ; Dopamine receptor ; choline acetyltransferase ; in situ hybridization ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In situ hybridization was used to study dopamine D2 receptor (D2R) and choline acetyltransferase (ChAT) mRNA expression in neurons of the rat forebrain, both on control animals and after a unilateral 6-hydroxydopamine (6-OHDA) lesion of midbrain dopamine neurons. D2R mRNA expressing neurons were seen in regions which are known to be heavily innervated by midbrain dopamine fibers such as caudate-putamen, nucleus accumbens and olfactory tubercle. ChAT mRNA expressing neurons were seen in caudate-putamen, nucleus accumbens and septal regions including vertical limb of the diagonal band. In caudate-putamen, approximately 55% of the medium sized neurons, which is the predominating neuronal cell-size in this region, were specifically labeled with the D2R probe. In addition, approximately 95% of the large size neurons in caudate-putamen were specifically labeled with both the D2R and ChAT probes, suggesting that most cholinergic neurons in the caudate-putamen express D2R mRNA. After a unilateral lesion of midbrain dopamine neurons, no change in the level of either D2R or ChAT mRNA were seen in the large size intrinsic cholinergic neurons in caudate-putamen. Similarily, no evidence was obtained for altered levels of D2R mRNA in medium size neurons in medial caudate-putamen, or nucleus accumbens. However, an increase in the number of medium size neurons expressing D2R mRNA was observed in the lateral part of the dopamine deafferented caudateputamen. Thus, it appears that midbrain dopamine deafferentation causes an increase in D2R mRNA expression in a subpopulation of medium size neurons in the lateral caudate-putamen.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00232197
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  • 8
    Electronic Resource
    Electronic Resource
    Simultaneous determination of cholecystokinin, dopamine, glutamate and aspartate in cortex and striatum of the rat using in vivo microdialysis (1991)
    Springer
    Amino acids 1 (1991), S. 365-373 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Glutamate ; Aspartate ; Dopamine ; Cholecystokinin ; Microdialysis ; Basal Ganglia
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Extracellular levels of cholecystokinin (CCK), dopamine (DA), glutamate (Glu) and aspartate (Asp) were simultaneously monitored in the frontoparietal cortex and the striatum of halothane-anaesthetized rats using in vivo microdialysis. Under basal conditions, cortical and striatal CCK levels were 3.11 ± 0.39 pM and 2.76 ± 0.15 pM, respectively. Local KCl (10−1 M) and bicuculline (10−4 M) co-application in cortex or striatum increased the CCK levels 18-fold and 26-fold, respectively. The DA level in striatum was 3.78 ± 0.28 nM and the local perfusion with KCl + bicuculline led to a 45-fold increase. The cortical and striatal outputs of Glu were of the order of 2 · 10−6 M and Asp levels were around 6 · 10−7 M. Local stimulation with KCl (10−1 M) and bicuculline (10−4 M) caused a small increase (2 fold) in cortical and striatal levels of Glu and Asp. The addition of KCl (10−1 M) and bicuculline (10−4 M) to the cortical perfusion medium did not modify CCK, DA or Glu concentrations in striatum. These results demonstrate that CCK, DA, Glu and Asp may be simultaneously monitored in vivo and support the idea that their extracellular levels recovered in the microdialysis perfusates could be derived from neuronal pools.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00814005
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  • 9
    Electronic Resource
    Electronic Resource
    Prevention of mortality induced by perinatal asphyxia: Hypothermia or glutamate antagonism? (1993)
    Springer
    Amino acids 5 (1993), S. 413-419 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Asphyxia ; Hypothermia ; Glutamate receptors ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Perinatal asphyxia was induced by keeping pups-containing uterus horns, removed by hysterectomy, in a 37°C or a 30°C water bath. Asphyxia for a period of 21–22 min at 37°C led to a 97% mortality within the first 20 min period following delivery. When the asphyctic period was extended to more than 22 min all the pups died following delivery. When the asphyxia was induced at 30°C, 100% of the delivered pups survived and were accepted by surrogate mothers. The protective effect of hypothermia could be observed even when the pups-containing uterus horns were exposed to a 45–46 min asphyctic period. Pretreatment with dizocilpine (0.2 mg/kg s.c.), or 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)quinoxaline (NBQX) (3–30 mg/kg s.c.), administered to the mothers one hour before hysterectomy, reduced slightly the mortality induced by a 21–22 min asphyctic period at 37°C. An increase in survival following a 22–23 min asphyctic period could only be observed after the highest dose of NBQX.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00806959
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  • 10
    Electronic Resource
    Electronic Resource
    Neuronal dependence of extracellular dopamine, acetylcholine, glutamate, aspartate and gamma-aminobutyric acid (GABA) measured simultaneously from rat neostriatum using in vivo microdialysis: reciprocal interactions (1992)
    Springer
    Amino acids 2 (1992), S. 157-179 
    Details
    ISSN: 1438-2199
    Keywords: Amino acids ; Dopamine ; Acetylcholine ; Glutamate ; Aspartate ; Gamma-aminobutyric acid (GABA) ; Striatum ; Microdialysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The neuronal origin of extracellular levels of dopamine (DA), acetylcholine (ACh), glutamate (Glu), aspartate (Asp) and gamma-aminobutyric acid (GABA) simultaneously collected from the neostriatum of halothane anaesthetized rats with in vivo microdialysis was studied. The following criteria were applied (1) sensitivity to K+-depolarization; (2) sensitivity to inhibition of synaptic inactivation mechanisms; (3) sensitivity to extracellular Ca2+; (4) neuroanatomical regionality; sensitivity to selective lesions and (5) sensitivity to chemical stimulation of the characterized pathways. It was found that: (1) Extracellular DA levels found in perfusates collected from the neostriatum fulfills all the above criteria and therefore the changes in extracellular DA levels measured with microdialysis reflect actual release from functionally active nerve terminals, and so reflect ongoing synaptic transmission. (2) Changes in neostriatal ACh levels reflect neuronal activity, provided that a ACh-esterase inhibitor is present in the perfusion medium. (3) Extracellular Glu, Asp and GABA could be measured in different perfusion media in the rat neostriatum and probably reflect metabolic as well as synaptic release. However, (4) the majority of the extracellular GABA levels found in perfusates collected from the neostriatum may reflect neuronal release, since GABA levels were increased, in a Ca2+-dependent manner, by K+-depolarization, and could be selectively decreased by an intrinsic neostriatal lesion. (5) It was not possible to clearly distinguish between the neuronal and the metabolic pools of Glu and Asp, since neostriatal Glu and Asp levels were only slightly increased by K+-depolarization, and no changes were seen after decortication. A blocker of Glu re-uptake, DHKA, had to be included in the perfusion medium in order to monitor the effect of K+-depolarization on Glu and Asp levels. Under this condition, it was found (6) that neostriatal Glu and Asp levels were significantly increased by K+-depolarization, although only increases in the Glu levels were sensitive to Ca2+ in the perfusion medium, suggesting that Glu but not Asp is released from vesicular pools. (7) Evidence is provided that selective stimulations of nigral DA cell bodies may lead to changes in release patterns from DA terminals in the ipsilateral neostriatum, which are in turn followed by discrete changes in extracellular levels of GABA and Glu in the same region. Finally, some methodological considerations are presented to clarify the contribution of neuronal release to extracellular levels of amino acid neurotransmitters in the rat neostriatum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00806086
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