Effect of beta-casomorphin on neonatal sleep in rats

Tomi Taira, Leena A. Hilakivi, Jouni Aalto, Ilkka Hilakivi

Research output: Contribution to journalArticlepeer-review

29 Scopus citations


The effects of bovine beta-casomorphin(1-7) (Tyr-Pro-Phe-Pro-Gly-Pro-Ile) on neonatal sleep in rats were studied. The pups received intraperitoneal injections of beta-casomorphin(1-7) (1 mg, 5 mg, 10 mg, 50 mg, or 100 mg/kg) or a corresponding volume of sodium chloride. In any of the doses used, beta-casomorphin(1-7) had no effect on waking. Only 100 mg/kg caused significant changes in sleep: the percentage of quiet state of the total recording time (TRT) increased and the percentage of active sleep decreased. Beta-casomorphin(1-7) did not cause significant respiratory depression. Naloxone pretreatment (1 mg/kg IP) reversed the effects of beta-casomorphin(1-7) on sleep, a finding which suggests that opiate μ-receptors are involved in mediating the sleep effects of beta-casomorphin.

Original languageEnglish (US)
Pages (from-to)1-4
Number of pages4
Issue number1
StatePublished - 1990
Externally publishedYes


  • Beta-casomorphin(1-7)
  • Movement sensitive mattress
  • Naloxone
  • Neonatal
  • Rat
  • Sleep-wake behavior


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