<i>In vivo</i>Microdialysis of 5-Hydroxyindoleacetic Acid and Glutamic Acid in the Hamster Suprachiasmatic Nuclei

Glass, John D.; Hauser, Ursula; Randolph, W.; Rea, Micheal A.; Vries, Martinus J. De

doi:10.1093/icb/33.2.212

Cited by 10 publications

(6 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The significantly different levels of ezrin staining at ZT10 and ZT14 (Fig. 3) are consistent with rhythmic glutamate concentration in the SCN (35), in particular because ezrin staining was more intense at ZT14 when glutamate levels peak (35), in line with glutamate-induced PAP plasticity. Future biochemical and ultrastructural studies are, however, required to clarify whether increased ezrin immunoreactivity reflects ezrin protein synthesis at the onset of the night or differential ezrin availability for immunoreactivity staining based on sequestration or subcellular redistribution.…”

Section: Resultssupporting

confidence: 72%

Structural plasticity of perisynaptic astrocyte processes involves ezrin and metabotropic glutamate receptors

Lavialle

Aumann

Anlauf

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

219

264

View full text Add to dashboard Cite

The peripheral astrocyte process (PAP) preferentially associates with the synapse. The PAP, which is not found around every synapse, extends to or withdraws from it in an activity-dependent manner. Although the pre-and postsynaptic elements have been described in great molecular detail, relatively little is known about the PAP because of its difficult access for electrophysiology or light microscopy, as they are smaller than microscopic resolution. We investigated possible stimuli and mechanisms of PAP plasticity. Immunocytochemistry on rat brain sections demonstrates that the actin-binding protein ezrin and the metabotropic glutamate receptors (mGluRs) 3 and 5 are compartmentalized to the PAP but not to the GFAP-containing stem process. Further experiments applying ezrin siRNA or dominant-negative ezrin in primary astrocytes indicate that filopodia formation and motility require ezrin in the membrane/cytoskeleton bound (i.e., T567-phosphorylated) form. Glial processes around synapses in situ consistently display this ezrin form. Possible motility stimuli of perisynaptic glial processes were studied in culture, based on their similarity with filopodia. Glutamate and glutamate analogues reveal that rapid (5 min), glutamate-induced filopodia motility is mediated by mGluRs 3 and 5. Ultrastructurally, these mGluR subtypes were also localized in astrocytes in the rat hippocampus, preferentially in their fine PAPs. In vivo, changes in glutamatergic circadian activity in the hamster suprachiasmatic nucleus are accompanied by changes of ezrin immunoreactivity in the suprachiasmatic nucleus, in line with transmitter-induced perisynaptic glial motility. The data suggest that (i) ezrin is required for the structural plasticity of PAPs and (ii) mGluRs can stimulate PAP plasticity.A strocytes act as a third partner in synaptic signal processing by responding to neurotransmitters and by releasing "gliotransmitters" (1, 2). Structurally, the astrocyte functions mainly through its peripheral processes, which constitute approximately 80% of the cell's membrane (3). These peripheral astrocyte processes (PAPs) are frequently extremely fine (<50 nm) and display an extreme surface-to-volume ratio. They are rarely studied in live tissue, as they are not directly accessible to electrophysiology, cannot be isolated for biochemistry, and are smaller than microscopic resolution. However, they also wrap synapses, but most studies on glia-synaptic interaction can only indiscriminately refer to them as the astrocyte. At the ultrastructural level, the PAPs, although abundant in the neuropil, specifically prefer contacting synapses and dendrites versus axons (4). The synaptic wrapping is highly dynamic (5-9) and also activity-dependent even in the context of physiological functions, such as motor learning, daily fluctuations of the circadian clock, lactation, parturition, or dehydration (10-15). Here, we asked two questions about the structural basis of glia-synaptic interaction: What is the stimulus for PAP plasticity, and what are the intra...

show abstract

Section: Resultssupporting

confidence: 72%

Structural plasticity of perisynaptic astrocyte processes involves ezrin and metabotropic glutamate receptors

Lavialle

Aumann

Anlauf

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

219

264

View full text Add to dashboard Cite

show abstract

“…Taken together these results suggest that, in contrast to the dopaminergic system, the serotonergic system does not reflect primarily the aspects of formation of an association or even of behavioral strategies, but rather the stressful aspect of the situation by participating in the regulation of anxiety and defensive behavior (Deakin and Graeff, 1991;Glass et a)., 1993;Graeff, 1993;Young, 1993).…”

Section: Discussionmentioning

confidence: 94%

“…Under the experimental conditions described it was impossible to analyze 5-HT itself. Therefore, our assumption that 5-HIAA responses depend on 5-HT release is based on findings from other laboratories (Glass et al, 1993).…”

Section: Discussionmentioning

confidence: 99%

“…The dopaminergic projections to the prefrontal cortex have been implicated in the regulation of cognitive processes and working memory (Sawaguchi et al, 1990a,b;Sawaguchi and Goldman-Rakic, 1991;Schultz et al, 1993;Sokolowski et al, 1994). The serotonergic projections from the raphe nuclei seem to be involved in the control of anxiety and defensive behavior (Deakin and Graeff, 1991;Glass et al, 1993;Graeff, 1993;Young, 1993).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Dopaminergic and Serotonergic Neurotransmission Systems Are Differentially Involved in Auditory Cortex Learning: A Long‐Term Microdialysis Study of Metabolites

Stark

Scheich

1997

Journal of Neurochemistry

View full text Add to dashboard Cite

Auditory cortex has been shown to be a site of widespread neuronal learning processes even in the context of simple auditory conditioning behavior. In view of their presumed role in determining behavioral and motivational relevance of incoming information we investigated whether the dopaminergic and serotonergic systems are involved in auditory cortex learning. Using a chronic brain microdialysis technique over 4 days, samples from auditory cortex were obtained before, during, and after daily footshock avoidance training simultaneously from trained gerbils and passive control animals or pseudotrained animals. Because of detection limits of dopamine and serotonin in auditory cortex, the response profiles of extracellular homovanillic acid as the metabolite of the dopaminergic system and of 5‐hydroxyindoleacetic acid as the metabolite of the serotonergic system were determined from consecutive dialysis samples each day. The response of the dopaminergic system appeared to reflect the initial formation of the behaviorally relevant association exclusively during the first training day, whereas the serotonergic response appeared to correlate with the stress level of animals.

show abstract

“…From these, 94 were included. Screening of the reference lists only resulted in one additional publication [45]. The flow of included and excluded publications is presented in Figure 1.…”

Section: Resultsmentioning

confidence: 99%

Brain Microdialysate Monoamines in Relation to Circadian Rhythms, Sleep, and Sleep Deprivation – a Systematic Review, Network Meta-analysis, and New Primary Data

Menon¹,

Nolten²,

Achterberg³

et al. 2019

Journal of Circadian Rhythms

View full text Add to dashboard Cite

Disruption of the monoaminergic system, e.g. by sleep deprivation (SD), seems to promote certain diseases. Assessment of monoamine levels over the circadian cycle, during different sleep stages and during SD is instrumental to understand the molecular dynamics during and after SD. To provide a complete overview of all available evidence, we performed a systematic review. A comprehensive search was performed for microdialysis and certain monoamines (dopamine, serotonin, noradrenaline, adrenaline), certain monoamine metabolites (3,4-dihydroxyphenylacetic acid (DOPAC), 5-hydroxyindoleacetic acid (5-HIAA)) and a precursor (5-hydroxytryptophan (5-HTP)) in PubMed and EMBASE. After screening of the search results by two independent reviewers, 94 publications were included. All results were tabulated and described qualitatively. Network-meta analyses (NMAs) were performed to compare noradrenaline and serotonin concentrations between sleep stages. We further present experimental monoamine data from the medial prefrontal cortical (mPFC). Monoamine levels varied with brain region and circadian cycle. During sleep, monoamine levels generally decreased compared to wake. These qualitative observations were supported by the NMAs: noradrenaline and serotonin levels decreased from wakefulness to slow wave sleep and decreased further during Rapid Eye Movement sleep. In contrast, monoamine levels generally increased during SD, and sometimes remained high even during subsequent recovery. Decreases during or after SD were only reported for serotonin. In our experiment, SD did not affect any of the mPFC monoamine levels. Concluding, monoamine levels vary over the light-dark cycle and between sleep stages. SD modifies the patterns, with effects sometimes lasting beyond the SD period.

show abstract

In vivoMicrodialysis of 5-Hydroxyindoleacetic Acid and Glutamic Acid in the Hamster Suprachiasmatic Nuclei

Cited by 10 publications

References 11 publications

Structural plasticity of perisynaptic astrocyte processes involves ezrin and metabotropic glutamate receptors

Structural plasticity of perisynaptic astrocyte processes involves ezrin and metabotropic glutamate receptors

Dopaminergic and Serotonergic Neurotransmission Systems Are Differentially Involved in Auditory Cortex Learning: A Long‐Term Microdialysis Study of Metabolites

Brain Microdialysate Monoamines in Relation to Circadian Rhythms, Sleep, and Sleep Deprivation – a Systematic Review, Network Meta-analysis, and New Primary Data

Contact Info

Product

Resources

About