EFFECTS OF METHADONE USE DURING PREGNANCY ON HUMAN PLACENTAL OPIOID RECEPTORS

Human placenta was used to investigate the effects of chronic methadon e use during pregnancy on villus tissue opioid receptors. Patients inc luded in this investigation received 35-60 mg methadone per day. Metha done-exposed placenta villus tissue had no detectable opioid receptor binding sites measured by tritiated opioid agonists. In vitro release of acetylcholine and hCG from trophoblast tissue of methadone-exposed placentas was not modulated by opioids. Absence of opioid receptor bin ding sites and their two mediated responses in trophoblast tissue of p lacentas obtained from patients with documented chronic methadone use during pregnancy indicate that the receptors were down regulated or de sensitized.