Table 1.
Presence of components of the serotonin system in homogenates of human placental tissue.
| Gestational period | mRNA | Protein | Activity | Study | |
|---|---|---|---|---|---|
| Enzymes | |||||
| TPH1 | First trimester | + a | n.a. | + g | (68) |
| Term | + a | n.a. | + g | (68) | |
| First trimester | + b | (+) e | + g | (69) | |
| Term | (+) b | + e | + g | (69) | |
| Term | (+)/− a | n.a. | n.a. | (70) | |
| TPH2 | First trimester | − a | n.a. | + g | (68) |
| Term | + a | n.a. | + g | (68) | |
| First trimester | (+) b | n.a. | + g | (69) | |
| Term | (+) b | n.a. | + g | (69) | |
| Term | (+)/− a | n.a. | n.a. | (70) | |
| MAOA | First trimester | + b | + e | + | (69) |
| Term | + b | + e | + | (69) | |
| Term | + b | + f | + | (71) | |
| Term | + b | n.a. | n.a. | (72) | |
| Term | n.a. | + h | + | (73) | |
| MAOB | Term | n.a. | − h | − | (73) |
| Term | + b | n.a. | n.a. | (71) | |
| Term | + b | n.a. | n.a. | (72) | |
| Transporters | |||||
| OCT1 | First trimester | + a | n.a. | n.a. | (74) |
| (SLC22A1) | Term | + a | n.a. | n.a. | (74) |
| Term | (+) a | n.a. | n.a. | (75) | |
| Term | − a | n.a. | n.a. | (76) | |
| Term | − b | n.a. | n.a. | (77) | |
| OCT2 | First trimester | + a | n.a. | n.a. | (74) |
| (SLC22A2) | Term | (+) a | n.a. | n.a. | (74) |
| Term | (+) a | n.a. | n.a. | (75) | |
| Term | − a | n.a. | n.a. | (76) | |
| Term | − b | n.a. | n.a. | (77) | |
| OCT3 | First trimester | + a | n.a. | n.a. | (74) |
| (SLC22A3) | First trimester | (+) a | (+) d | n.a. | (75) |
| Second trimester | + a | + d | n.a. | (75) | |
| Term | (+) a | n.a. | n.a. | (74) | |
| Term | + a | + d | n.a. | (75) | |
| Term | + a | n.a. | n.a. | (76) | |
| Term | + b | n.a. | n.a. | (77) | |
| PMAT (SLC29A4) | Term | (+) a | n.a. | n.a. | (75) |
| VMAT2 (SLC18A2) | Term | (+) b | n.a. | n.a. | (78) |
| Receptors | |||||
| HTR2A | Term | + b | + e | n.a | (79) |
| Term | + b | + e | n.a | (80) | |
| HTR2B | Term | + a | n.a. | n.a. | (81) |
| HTR1D | Term | + a | n.a. | n.a. | (68) |
| HTR1E | Term | + a | n.a. | n.a. | (68) |
| HTR5A | Term | + a | n.a. | n.a. | (68) |
| HTR5B | Term | + a | n.a. | n.a. | (68) |
a
RT−qPCR (quantitative reverse transcriptase−polymerase chain reaction).
b
RT−PCR (reverse transcription−end point PCR).
c
ddPCR (digital droplet PCR).
d
LC−MS/MS (liquid chromatography coupled with tandem mass spectrometry).
e
Western blot.
f
ELISA (enzyme-linked immunosorbent assay).
g
The activity assay used does not distinguish between the activity of TPH1 and TPH2.
h
Binding studies with isoform-specific inhibitors.
n.a.: not analysed; +: detected; −: not detected; (+): low levels detected; (+)/−: low levels detected or below detection limit.