Effects of sex hormones, forskolin, and nicotine on choline
acetyltransferase activity in human isolated placenta.
Wessler I, Schwarze S, Brockerhoff P, Bittinger F, Kirkpatrick CJ, Kilbinger
H.
Department of Pharmacology, Universitat Mainz, Obere Zahlbacher Strasse 67,
55101 Mainz, Germany. Wessler@mail.uni-mainz.de
The activity of choline acetyltransferase (ChAT) was investigated in the human
placenta before and after long-term incubation (24 h) to test the effects of sex
hormones, nicotine and forskolin. ChAT activity differed considerably between
the amnion (0.03 micromol/mg protein/h) and the villus (0.56). After long-term
incubation, ChAT activity persisted in the latter but declined in the amnion.
Neither sex hormones (beta-estradiol, testosterone, progesterone; 10 or 100 nM
each) nor follicle stimulating hormone and luteinizing hormone (FSH/LH; 8.4 U/ml
each) modified ChAT activity. Also nicotine (1 nM-100 microM) did not affect
ChAT activity. Forskolin, an activitor of adenylyl cyclase, reduced ChAT
activity in the villus but not in amnion. The present model offers the
possibility to investigate ChAT regulation in intact tissue under long-term
incubation. The risks of maternal smoking during pregnancy cannot be attributed
to an effect of nicotine on placental ChAT activity. Differences in the
regulation of ChAT appear to exist between neuronal and nonneuronal cells.