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Serotonin Content (serotonin + content)

Distribution by Scientific Domains
Life Sciences71%

Selected Abstracts

Serotonin content of normal and inflamed appendix: a possible role of serotonin in acute appendicitis,

APMIS, Issue 11 2008
MOHAMMAD VASEI
The appendix is lined by a mucosa which has many neuroendocrine cells containing serotonin. Local release of serotonin can act as a mediator of inflammation. In this study we explored the serotonin content of the neuroendocrine cells of the appendixes removed for clinical diagnosis of appendicitis. Appendix specimens were divided into three groups: Acute appendicitis (AA), non-appendicitis (NA), and follicular hyperplasia (FH). Normal appendix specimens from patients undergoing elective abdominal surgery were used as the control group (NL). All sections were exposed to proteinase K, incubated with anti-serotonin, chromogranin A, and synaptophysin antibodies, and treated with the LSAB kit. Polygonal cells were seen within the crypt epithelium (enterochromaffin cell, EC) and within the lamina propria (subepithelial neuroendocrine cell, SNC). In AA, only 16 cases (64%) showed serotonin staining in non-destructed glands. There was a significant reduction in the number of ECs in AA compared to the FH (96%), NA (100%) and NL (100%) groups (P<0.001). Chromogranin and synaptophysin immunostaining also showed a significant reduction in the number of ECs in AA compared with the other three groups (P<0.001). SNC serotonin reactivity was lower in the AA group compared with the other groups (p<0.001). The inflamed appendix is markedly depleted of serotonin in the epithelium and lamina propria. Local serotonin release from ECs and SNCs in the appendix may act as an inflammatory mediator in appendicitis and is likely to be the source of raised blood serotonin in AA. [source]

Quantitative measurement of serotonin synthesis and sequestration in individual live neuronal cells

JOURNAL OF NEUROCHEMISTRY, Issue 5 2005
J. Balaji
Abstract Synthesis and subsequent sequestration into vesicles are essential steps that precede neurotransmitter exocytosis, but neither the total neurotransmitter content nor the fraction sequestered into vesicles have been measured in individual live neurons. We use multiphoton microscopy to directly observe intracellular and intravesicular serotonin in the serotonergic neuronal cell line RN46A. We focus on how the relationship between synthesis and sequestration changes as synthesis is up-regulated by differentiation or down-regulated by chemical inhibition. Temperature-induced differentiation causes an increase of about 60% in the total serotonin content of individual cells, which goes up to about 10 fmol. However, the number of vesicles per cell increases by a factor of four and the proportion of serotonin sequestered inside the vesicles increases by a factor of five. When serotonin synthesis is inhibited in differentiated cells and the serotonin content goes down to the level present in undifferentiated cells, the sequestered proportion still remains at this high level. The total neurotransmitter content of a cell is, thus, an unreliable indicator of the sequestered amount. [source]

Three-photon microscopy shows that somatic release can be a quantitatively significant component of serotonergic neurotransmission in the mammalian brain

JOURNAL OF NEUROSCIENCE RESEARCH, Issue 15 2008
S.K. Kaushalya
Abstract Recent experiments on monoaminergic neurons have shown that neurotransmission can originate from somatic release. However, little is known about the quantity of monoamine available to be released through this extrasynaptic pathway or about the intracellular dynamics that mediate such release. Using three-photon microscopy, we directly imaged serotonin autofluorescence and investigated the total serotonin content, release competence, and release kinetics of somatic serotonergic vesicles in the dorsal raphe neurons of the rat. We found that the somata of primary cultured neurons contain a large number of serotonin-filled vesicles arranged in a perinuclear fashion. A similar distribution is also observed in fresh tissue slice preparations obtained from the rat dorsal raphe. We estimate that the soma of a cultured neuron on an average contains about 9 fmoles of serotonin in about 450 vesicles (or vesicle clusters) of ,370 nm average diameter. A substantial fraction (>30%) of this serotonin is released with a time scale of several minutes by K+ -induced depolarization or by para-chloroamphetamine treatment. The amount of releasable serotonin stored in the somatic vesicles is comparable to the total serotonin content of all the synaptic vesicles in a raphe neuron, indicating that somatic release can potentially play a major role in serotonergic neurotransmission in the mammalian brain. © 2008 Wiley-Liss, Inc. [source]

Serotonin content of normal and inflamed appendix: a possible role of serotonin in acute appendicitis,

APMIS, Issue 11 2008
MOHAMMAD VASEI
The appendix is lined by a mucosa which has many neuroendocrine cells containing serotonin. Local release of serotonin can act as a mediator of inflammation. In this study we explored the serotonin content of the neuroendocrine cells of the appendixes removed for clinical diagnosis of appendicitis. Appendix specimens were divided into three groups: Acute appendicitis (AA), non-appendicitis (NA), and follicular hyperplasia (FH). Normal appendix specimens from patients undergoing elective abdominal surgery were used as the control group (NL). All sections were exposed to proteinase K, incubated with anti-serotonin, chromogranin A, and synaptophysin antibodies, and treated with the LSAB kit. Polygonal cells were seen within the crypt epithelium (enterochromaffin cell, EC) and within the lamina propria (subepithelial neuroendocrine cell, SNC). In AA, only 16 cases (64%) showed serotonin staining in non-destructed glands. There was a significant reduction in the number of ECs in AA compared to the FH (96%), NA (100%) and NL (100%) groups (P<0.001). Chromogranin and synaptophysin immunostaining also showed a significant reduction in the number of ECs in AA compared with the other three groups (P<0.001). SNC serotonin reactivity was lower in the AA group compared with the other groups (p<0.001). The inflamed appendix is markedly depleted of serotonin in the epithelium and lamina propria. Local serotonin release from ECs and SNCs in the appendix may act as an inflammatory mediator in appendicitis and is likely to be the source of raised blood serotonin in AA. [source]

Effect of serotonin-acting agents on the serotonin content of immune cells.

CELL BIOCHEMISTRY AND FUNCTION, Issue 5 2007
A peculiar observation
Abstract The effect of the tryptophan hydroxylase inhibitor, PCPA methylester, the serotonin reuptake inhibitor fluoxetine and MAO-A inhibitor clorgyline on the serotonin content of rat immune cells was studied, using labelled antibodies and flow cytometry. Each molecule significantly increased in males the serotonin concentration of peritoneal lymphocytes and the monocyte-macrophage-granulocyte group (mo-gran), however the agents were ineffective towards mast cells. In females fluoxetine and clorgyline increased the serotonin concentration in peritoneal lymphocytes and mo-gran. Fluoxetine also increased the serotonin level in mast cells. Thymus was absolutely resistant to the drugs in both genders. The results call attention (1) to the reverse effect of serotonin-acting agents on immune cells, (2) to the influence of the milieu where the cell is located and (3) the effect of gender. Copyright © 2006 John Wiley & Sons, Ltd. [source]