Role of neurotransmitters and teratogens on palate development.

Neurotransmitters regulate palate shelf reorientation. Acetylcholine and serotonin stimulate, whereas GABA inhibits reorientation. Serotonin stimulates cell movement in an in vitro chemotactic system. Diazepam may cause cleft palate by mimicking GABA. Diazepam sensitivity may be caused by genotypic differences in a GABA-ergic system in the embryo.