The presence and role of the dopamine DA-2 receptor in the human decidua.
OBJECTIVE
Our objectives were to identify the presence of the dopamine DA-2 receptor in human decidua and to study its function in human parturition.


METHODS
Human term decidual tissues were obtained during vaginal delivery and then homogenized. The P3 fraction was prepared for a radiolabeled receptor assay with [3H] spiperone as the ligand. Human decidual tissues obtained at cesarean section before the onset of labor were incubated in Krebs-Ringer buffer at 37 degrees C for 30 minutes in the presence of dopamine with or without (-)-sulpiride. The level of prostaglandin (PG) F in the medium was measured with a RIA kit. Differences were assessed with the Wilcoxon non-parametric test.


RESULTS
Scatchard analysis showed a single class of binding sites having an equilibrium dissociation constant (Kd) of 2.25 +/- 0.59 nM (mean +/- SD) and a maximum binding capacity (Bmax) value of 166.5 +/- 77.7 fmol/mg protein (n = 3). Dopamine significantly increased the production of PGF. This stimulatory effect of dopamine was suppressed by (-)-sulpiride (p < 0.05; n = 7).


CONCLUSIONS
The DA-2 receptor was demonstrated in the human decidua. Dopamine can stimulate PGF production via this receptor.
Arai
F
F
Department of Obstetrics and Gynecology, Okayama University Medical School, Japan.
Kishimoto
Y
Y
Tada
K
K
Kondo
Y
Y
Kudo
T
T
D003656:Decidua / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism; D004298:Dopamine / Q000494:pharmacology; D005260:Female; D006801:Humans; D011247:Pregnancy; D011460:Prostaglandins F / Q000096:biosynthesis; D011869:Radioligand Assay; D017448:Receptors, Dopamine D2 / Q000032:analysis* / Q000378:metabolism; D013134:Spiperone / Q000378:metabolism; D013469:Sulpiride / Q000494:pharmacology; D014316:Tritium
D011460:Prostaglandins F; D017448:Receptors, Dopamine D2; D014316:Tritium; D013134:Spiperone; D013469:Sulpiride; D004298:Dopamine