Differences Between Intracellular Platelet and Brain Proteins that Bind Serotonin

Tamir, Hadassah; Bebirian, R; Casper, Diana

doi:10.1111/j.1471-4159.1980.tb07857.x

Cited by 33 publications

(14 citation statements)

References 40 publications

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“…Although this protein (SBP) has also been suggested as being actin-like in its properties (37), it is reported to have a low Kd for 5HT (101 to 10-8 M; see ref. 32) and an apparent Mr on NaDodSO4/ PAGE of about 60,000 (32). We have been unable to show such high-affinity binding in our preparations.…”

Section: Resultscontrasting

confidence: 63%

“…been reported to stimulate the binding of 5HT to a high-affinity 5HT-bindihg protein isolated by Tamir and co-workers (31)(32)(33), also stimulated the binding of SHT to actin and to (22). The gels were stained with Coomassie brilliant blue G-250 and destained as described by Fairbanks et al (22).…”

Section: Resultsmentioning

confidence: 99%

“…Tamir and co-workers have described a Fe2+-stimulated 5HT-binding protein in rat brain (31)(32)(33). Although this protein (SBP) has also been suggested as being actin-like in its properties (37), it is reported to have a low Kd for 5HT (101 to 10-8 M; see ref.…”

Section: Resultsmentioning

confidence: 99%

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Serotonin binds specifically and saturably to an actin-like protein isolated from rat brain synaptosomes.

Small¹,

Wurtman²

1984

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

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A soluble serotonin-binding protein was identified in a high-speed supernatant fraction of an osmotically shocked rat brain synaptosome (P2) preparation. The binding of serotonin was saturable (B. = 6.0 umol per mg of protein) and was specific for serotonin and a few structurally related compounds including dopamine and norepinephrine. Binding of serotonin (1 ,uM) was inhibited "40% by chlorpromazine (10 AuM). The affinity of serotonin for the binding protein was low in the crude extract (Kd = 1.7 X 10-3 M). However, on purification by chromatography on a column of phenothiazine agarose, a higher affinity (Kd = 10-5 M) binding component was also observed. The purified protein was greatly enriched in a polypeptide Of Mr of 43,000 that comigrated on polyacrylamide gel with skeletal muscle actin. Muscle actin also bound serotonin, and the binding to actin was similar to that of the purified protein in both the specificity of the binding and the affinity for serotonin. It is likely that the serotoninbinding protein is identical to cytoplasmic G-actin or an actinlike protein of similar molecular weight.

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Section: Resultscontrasting

confidence: 63%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Serotonin binds specifically and saturably to an actin-like protein isolated from rat brain synaptosomes.

Small¹,

Wurtman²

1984

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

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“…Free plasma serotonin is either rapidly metabolized by monoamine oxidase (MAO) A within the endothelium [9] or the placental syncytiotrophoblast [10] or is taken up by platelets [11]. Altered serotonin disposition could be hypothesized in preeclamptic subjects, since both endothelial dysfunction and reduced functional placental mass are typical.…”

Section: The Agentmentioning

confidence: 99%

The role of serotonin in the preeclampsia-eclampsia syndrome

Weiner

1990

Cardiovasc Drug Ther

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The cause of preeclampsia, a syndrome unique to human pregnancy, is unknown. There is presently no effective pharmacologic therapy once the symptoms have appeared. Only delivery is curative. Preeclampsia likely has multiple etiologies, each of which activates a common pathway, culminating in diffuse endothelial damage, vasospasm, and hypertension. Current investigation suggests that serotonin has a pivotal role in the genesis of preeclamptic hypertension. The evidence, as obtained from human and animal study, is reviewed in this article, and areas in need of further study are highlighted. A modified series of Koch's postulates is employed for a framework. Serotonin is the agent but does not directly cause the hypertension. Rather, it is suggested that in a milieu characterized by a reduction in endothelial-derived relaxing factor and prostacyclin, serotonin augments the smooth muscle response to normally occurring concentrations of endogenous vasopressors. It is delivered to the site of action (the microvasculature) by the platelet, whose aggregation is encouraged by dysfunctional endothelium. Either inhibition of the delivery mechanism by a low, daily dose of aspirin, or inhibition of the peripheral serotonin type 2 (5HT2) receptor, effectively controls the hypertension.

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“…Specific 5-HT uptake inhibitors should be used to study this point. The clear difference between proteins that bind 5-HT in rat platelets and brain synaptosomes (Tamir et al 1980) indicates possible differences in the storage of 5-HT. In addition, the inhibition of 5-HT uptake by copper and methyl mercury was quite similar in human blood platelets ) and in rat hypothalamic synaptosomes (Komulainen & Tuomisto 1981b & c).…”

Section: Controlmentioning

confidence: 99%

Enhancement of 5‐Hydroxytryptamine Uptake in Rabbit Hypothalamic Synaptosomes but not in Blood Platelets by Zinc and Lead ex Vivo

Komulainen

1983

Acta Pharmacologica et Toxicologica

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Lead (0.2%), zinc (0.5%) or their combination was given to rabbits as acetate salts in drinking water for 2 or 4 weeks. Cerebral Pb increased within exposure time but the increase of Zn was marginal when given alone. After combination of P b S Zn, blood Pb increased but Zn decreased as compared to the administration of the single metal alone. Concurrently brain Pb increased but remained at a lower level as compared with solePb administration while brain Zn did not differ from controls. The uptake of 5-hydroxytryptamine (5-HT) into hypothalamic synaptosomes increased 70-85% with Pb, Zn and PbSZn after 2 weeks and 93% with Zn and 76% with Pb+Zn after 4 weeks. Dopamine uptake into striatal synaptosomes did not change. Zn decreased . endogenous noradrenaline concentrations by 21 % and Pb+Zn that of 5-HT by 36% in the striatum. P b f Zn decreased cortical dopamine concentrations by 26%. Concurrently, 5-HT uptake in blood platelets, platelet numbers and their content of endogenous 5-HT did not change significantly. These results indicate that high Zn and Pb have parallel effects on 5-HT uptake in hypothalamic synaptosomes and their combination may be neurochemically more toxic than the individual metals. The increase of 5-HT uptake in hypothalamic synaptosomes but not in blood platelets requires further methodological work to explain the differences between synaptosomes and platelets.

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Differences Between Intracellular Platelet and Brain Proteins that Bind Serotonin

Cited by 33 publications

References 40 publications

Serotonin binds specifically and saturably to an actin-like protein isolated from rat brain synaptosomes.

Serotonin binds specifically and saturably to an actin-like protein isolated from rat brain synaptosomes.

The role of serotonin in the preeclampsia-eclampsia syndrome

Enhancement of 5‐Hydroxytryptamine Uptake in Rabbit Hypothalamic Synaptosomes but not in Blood Platelets by Zinc and Lead ex Vivo

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