title: Transient apnea after an enkephalin analogue in the preterm rabbit.
abstract: FK 33-824, a potent enkephalin analogue was administered systemically, 0.5-5 mg/kg to preterm neonatal rabbits. A marked decrease in respiratory frequency as well as irregular breathing and apneic spells was recorded at 5 mg/kg. Tidal volume was not affected. The enkephalin-induced respiratory depression was restored immediately after naloxone (10 mg/kg). Bases on the results it may be speculated upon whether brain stem enkephalin neurons are involved in the pathogenesis of neonatal transient apnea and irregular breathing.
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D001049:Apnea / Q000139:chemically induced / Q000503:physiopathology*; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; D004305:Dose-Response Relationship, Drug; D004723:Endorphins / Q000494:pharmacology*; D004745:Enkephalins / Q000494:pharmacology*; D005260:Female; D009270:Naloxone / Q000494:pharmacology; D011247:Pregnancy; D011817:Rabbits
chemical_list: D004723:Endorphins; D004745:Enkephalins; D009270:Naloxone; D005405:D-Ala(2),MePhe(4),Met(0)-ol-enkephalin