title: Effects of morphine on spontaneous activity of 18-day rat fetus.
abstract: The effects of morphine on spontaneous activity of 18-day fetal rats have been observed in utero. Morphine injected subcutaneously in the dam caused a decrease in fetal spontaneous activity which was dose-dependent. The maximum depression of activity occurred after 20 mg/kg was administered to the dam. Activity returned to control levels following naloxone administration to the dam. Fetuses which had been chronically exposed to morphine from days 7 through 17 and observed on day 18 of gestation became hyperactive following administration of naloxone to the dam. This is thought to represent fetal withdrawal.
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D008431:Maternal-Fetal Exchange; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D009270:Naloxone / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D012018:Reflex / Q000187:drug effects; D013375:Substance Withdrawal Syndrome / Q000209:etiology
chemical_list: D009270:Naloxone; D009020:Morphine