Serotonin uptake by bovine pulmonary artery endothelial cells in culture. I. Characterization

1986 ◽  
Vol 250 (5) ◽  
pp. C761-C765 ◽  
Author(s):  
S. L. Lee ◽  
B. L. Fanburg
Keyword(s):  
Endothelial Cells ◽  
Pulmonary Artery ◽  
Serotonin Uptake ◽  
High Affinity ◽  
Total Uptake ◽  
Cells In Culture ◽  
High Concentrations ◽  
5 Ht Uptake

Serotonin (5-HT) uptake by bovine pulmonary artery endothelial cells in culture was measured at 5-HT concentrations of 1.5 X 10(-8) to 10(-3) M. The uptake increased linearly at concentrations of 10(-5) to 10(-3) M 5-HT, and the slope for uptake was 1.276 X 10(6) pmol 5-HT X 10(6) cells-1 X 30 min-1 X M concentration-1. The slope for uptake at 5-HT concentrations less than 10(-7) M was 7.10 X 10(6) pmol X 10(6) cells-1 X 30 min-1 X M concentration-1. With subtraction of the slope for linear uptake obtained at high concentrations of 5-HT from total uptake of 5-HT, a curve showing saturable uptake at concentrations greater than 10(-6) to 10(-5) M was obtained. Lineweaver-Burk analysis of the data yielded a saturated value of high-affinity transport of 6.25 pmol X 10(6) cells-1 X 30 min-1 and a Km of 10(-6) M. At 5-HT concentrations of 1.5 X 10(-8) to 5 X 10(-7) M, uptake was inhibited 75-80% by exposure to 4 degrees C or by absence of sodium in the medium; absence of sodium did not affect uptake at 5-HT concentrations greater than 10(-5) M, and 4 degrees C was less effective in inhibiting uptake at high 5-HT concentrations. Imipramine markedly inhibited uptake at low, but not at high, 5-HT concentrations. Ouabain only partially inhibited 5-HT uptake, but inhibition was more pronounced at low 5-HT concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Serotonin uptake by bovine pulmonary artery endothelial cells in culture. II. Stimulation by hypoxia

1986 ◽  
Vol 250 (5) ◽  
pp. C766-C770 ◽  
Author(s):  
S. L. Lee ◽  
B. L. Fanburg
Keyword(s):  
Endothelial Cells ◽  
Pulmonary Artery ◽  
Cell Number ◽  
Morphological Evidence ◽  
Monoamine Oxidase Activity ◽  
Trypan Blue Exclusion ◽  
Cells In Culture ◽  
Low Concentrations ◽  
5 Ht Uptake ◽  
Stimulation Of

Exposure of bovine pulmonary artery endothelial cells to 3% O2 resulted in approximately twofold stimulation of serotonin (5-HT) uptake after 24-48 h when compared with cells exposed to 20% O2. The enhanced uptake was reversed after 48 h when cells were again placed in 20% O2. The stimulation was not observed after 0.5 or 2 h of exposure to hypoxia. The stimulation was present when iproniazid blocked conversion of 5-HT to 5-hydroxyindole-3-acetic acid, indicating that enhanced uptake did not occur through augmentation of monoamine oxidase activity. Stimulation of uptake by hypoxia occurred at low concentrations of 5-HT (up to 10(-6) M) but not at high 5-HT concentrations (greater than 10(-5) M) and was blocked by imipramine or absence of sodium from the medium, indicating that high-affinity transport and not diffusion of 5-HT was stimulated. Furthermore, exposure of cells to hypoxia did not produce morphological evidence of injury or change in protein content or trypan blue exclusion. The cell number of 3% O2-exposed cells was slightly reduced when compared with controls after 48 h. There was no change in cellular ATP or increase in lactate dehydrogenase in medium of cells exposed to 3% O2. Thus exposure of endothelial cells in culture to hypoxia stimulates the membrane activity of 5-HT accumulation with no evidence of injury to the cell.

An Analysis of the Time-Dependent Changes in Intracellular Calcium Concentration in Endothelial Cells in Culture Induced by Mechanical Stimulation

1993 ◽  
Vol 115 (2) ◽  
pp. 160-168 ◽  
Author(s):  
F. K. Winston ◽  
L. E. Thibault ◽  
E. J. Macarak
Keyword(s):  
Endothelial Cells ◽  
Cell Membrane ◽  
Pulmonary Artery ◽  
Intracellular Calcium ◽  
Mechanical Stimulation ◽  
Calcium Ion ◽  
Time Course ◽  
Mechanical Strain ◽  
Structural Response ◽  
Cells In Culture

When bovine pulmonary artery endothelial cells in culture are subjected to mechanical strain, their physiology is altered. Experimentally, this mechanical strain is generated by increased tension in the substrate to which the cells are attached and results in altered levels of fibronectin. Studies of the structural response of the endothelial cell suggest that this stimulus is transmitted to the cell membrane, organelles, and cytoskeleton by natural cell attachments in a quantifiable and predictable manner. This report examines altered intracellular calcium homeostasis as a possible messenger for the observed strain-induced physiologic response. In particular, using the intracellularly trapped calcium indicator dyes, Quin2 and Fura2, we observed changes in cytosolic free calcium ion concentration in response to biaxial strain of bovine pulmonary artery endothelial cells in culture. The magnitude and time course of this calcium transient resemble that produced by treatment with the calcium ionophore, Ionomycin, indicating that mechanical stimulation may alter cell membrane permeability to calcium. Additional experiments in the presence of EDTA indicated that calcium was also released from intracellular stores in response to strain. In order to explain the stretch-induced calcium transients, a first-order species conservation model is presented that takes into account both the cell’s structural response and the calcium homeostatic mechanisms of the cell. It is hypothesized that the cell’s calcium sequestering and pumping capabilities balanced with its mechanically induced changes in calcium ion permeability will determine the level and time course of calcium accumulation in the cytosol.

Histochemical Studies On The In Vitro 5-HT Uptake In Endothelial Cells

1981 ◽  
Author(s):  
T Kjellström ◽  
H Ahlman ◽  
F Dahlström ◽  
G Hansson ◽  
B Stenberg ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endothelial Cells ◽  
Factor Viii ◽  
Serotonin Uptake ◽  
Adult Rats ◽  
Pulmonary Endothelial Cells ◽  
Transmission Electron ◽  
5 Ht Uptake

Previous studies have shown that 5-HT is rapidly taken up by the endothelial cells and some investigations also suggested that serotonin is metabolized within these cells. In earlier studies on rat-lungs using a fluorescence histo- chemical method according to Hillarp - Falk we demonstrated that 5-HT was accumulated within the mast cells. Using this technique we could not demonstrate any specific uptake in the pulmonary endothelial cells. It was the purpose of the present investigation to further study the 5-HT uptake by isolated pulmonary endothelial cells.Methods Cells from the vascular intima of the pulmonary artery in adult rats were grown in a growth medium containing FCS. The endothelial nature of these cells was demonstrated using transmission electron microscopy and factor VIII analysis. Confluent endothelial cells were incubated with 5-HT and the cellular uptake was studied with fluorescence microscopy according to the Hillarp - Falk procedure.Results The endothelial cells were identified by the presence of Weibel-Palade bodies using transmission electron microscopy and the immunofluorescent demonstration of cellular factor VIII antigen. Cells not exposed to serotonin had no specific 5-HT fluorescense. After incubation with 5-HT at different concentrations there was a progressive uptake of the amine within the cells.Conclusions This study confirms previous reports on the specific serotonin uptake in endothelial cells. The Hillarp-Falk procedure seems suitable for further studies of serotonin uptake in cultured endothelial cells.

scholarly journals Differential serotonin uptake mechanisms at the human maternal-fetal interface

2021 ◽  
Author(s):  
Petra Bakovic ◽  
Maja Kesic ◽  
Marina Horvaticek ◽  
Meekha George ◽  
Maja Peric ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cord Blood ◽  
Blood Platelets ◽  
First Trimester ◽  
Dependent Manner ◽  
High Affinity ◽  
Placental Cells ◽  
5 Ht Uptake ◽  
Uptake Mechanisms ◽  
Maternal Fetal Interface

Cellular serotonin (5-HT) uptake is central to regulating local levels of 5-HT nearby its molecular targets. Here we studied 5-HT uptake mechanisms in primary placental cells and cord blood platelets, all isolated directly from the human tissues. All cell types took up 5-HT in a time- and temperature-dependent manner. In initial-rate experiments in primary term trophoblasts and cord blood platelets, saturation curves of active 5-HT uptake across multiple 5-HT concentrations were characteristic of the high-affinity transporter-mediated uptake mechanism. In contrast, primary term feto-placental endothelial cells displayed saturation kinetics only over the low-affinity range of 5-HT concentrations. Citalopram, a potent blocker of the serotonin transporter (SERT), inhibited 5-HT uptake in TMT, but not in PEC. In line with this, SERT mRNA was abundant in term trophoblasts, but sparse in feto-placental endothelial cells, while the opposite was found for transcripts of the low-affinity plasma membrane monoamine transporter (PMAT). 5-HT uptake into first trimester trophoblasts could not be saturated over the high-affinity range of 5-HT concentrations; as compared to term trophoblasts, first trimester trophoblasts expressed lower and higher levels of SERT and PMAT mRNAs, respectively. We conclude that 1) placental cells facing maternal and fetal blood at term of human pregnancy use different, low- and high-affinity, respectively, 5-HT uptake systems, 2) fetal platelets possess highly functional high-affinity 5-HT uptake activity, 3) 5-HT uptake mechanisms in trophoblasts change over the course of pregnancy. The multiple molecular mechanisms present for 5-HT uptake highlight the importance of maintaining 5-HT homeostasis at the maternal-fetal interface.

Monocrotaline pyrrole alters DNA, RNA and protein synthesis in pulmonary artery endothelial cells

1992 ◽  
Vol 262 (6) ◽  
pp. L740-L747 ◽  
Author(s):  
C. M. Hoorn ◽  
R. A. Roth
Keyword(s):  
Endothelial Cells ◽  
Protein Synthesis ◽  
Pulmonary Artery ◽  
Dna Content ◽  
Cell Number ◽  
Synthetic Activity ◽  
Cellular Activity ◽  
Rna And Protein Synthesis ◽  
High Concentrations ◽  
Monocrotaline Pyrrole

Administration of monocrotaline pyrrole (MCTP) to animals results in pulmonary vascular injury. Pulmonary vascular endothelium is a likely target for this pneumotoxicant. Cultured porcine pulmonary artery endothelial cells (PECs) treated with MCTP remain viable but are unable to divide and exhibit an altered morphology. Such responses raise a question about the extent to which affected cells carry out normal functions such as RNA and protein synthesis. Accordingly, the cellular activity of MCTP-treated PECs was examined in this study. PECs were treated with a single administration of MCTP or vehicle, and determinations of cell number, protein, and DNA content were made at times up to 7 days posttreatment. DNA, RNA, and protein synthesis were quantified by incorporation of [3H]thymidine, [3H]uridine, and [3H]leucine, respectively. Increases in cell number that occurred with time in the control cells were reduced in MCTP-treated cells. At 7 days posttreatment, both protein and DNA content increased above control levels. Synthesis of DNA, RNA, and protein continued in all treatment groups throughout the posttreatment period, but cells treated with high concentrations of MCTP showed less synthetic activity than controls during the initial 48 h posttreatment. By 7 days, MCTP-treated cells were producing significantly more DNA, RNA, and protein. These results indicate that cells treated with MCTP continue to synthesize DNA, resulting in an increased DNA content. In addition, treated cells continue to synthesize RNA and translate RNA into protein. Thus, cellular activity is maintained but altered substantially by MCTP exposure.

Characterization of L-glutamine transport by pulmonary artery endothelial cells

1991 ◽  
Vol 260 (4) ◽  
pp. L241-L246 ◽  
Author(s):  
K. Herskowitz ◽  
B. P. Bode ◽  
E. R. Block ◽  
W. W. Souba
Keyword(s):  
Endothelial Cells ◽  
Pulmonary Artery ◽  
Hormonal Regulation ◽  
Kinetic Studies ◽  
High Affinity ◽  
Sodium Dependent ◽  
Porcine Pulmonary Artery ◽  
External Ph ◽  
Glutamine Uptake

This study characterized the transport of L-glutamine by porcine pulmonary artery endothelial cells (PAECs). Uptake of 50 microM glutamine was determined and found to be linear for at least 45 min. The sodium-dependent velocity represented greater than 95% of the total uptake at all time points. Kinetic studies of glutamine uptake at concentrations between 0.005 and 10 mM showed a single saturable high-affinity carrier with a Michaelis constant of 100 +/- 6 microM and a maximal transport velocity of 1.0 +/- 0.08 nmol.mg protein-1.30s-1. Glutamine uptake by PAECs was markedly inhibited in the presence of L-cysteine, L-threonine, or L-alanine; lesser degrees of inhibition occurred when histidine and arginine were added. 2-Methylaminoisobutyric acid and 2-aminobicyclo [2,2,1]heptanedicarboxylic acid had little effect on glutamine uptake. Lithium did not substitute for sodium, strongly suggesting that L-glutamine was not transported by system N. Furthermore, transport of glutamine was not affected by hormones or by changes in external pH. Based on the intolerance of this high-affinity carrier to N-methylated substrate, its insensitivity to pH and hormonal regulation, and the failure of lithium to substitute for sodium, as well as its inhibition by alanine and cysteine, we conclude that in porcine pulmonary artery endothelial cells L-glutamine is predominantly taken up through system ASC.

Sign in / Sign up

Export Citation Format

Share Document