d-ala(2)-mephe(4)-met(0)-ol-enkephalin and Apnea

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.

Topics: Animals; Animals, Newborn; Apnea; D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; Dose-Response Relationship, Drug; Endorphins; Enkephalins; Female; Naloxone; Pregnancy; Rabbits