Effect of beta-casomorphin on neonatal sleep in rats.
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 mu-receptors are involved in mediating the sleep effects of beta-casomorphin.
Taira
T
T
University of Helsinki, Department of Physiology, Finland.
Hilakivi
L A
LA
Aalto
J
J
Hilakivi
I
I
D000595:Amino Acid Sequence; D000818:Animals; D000831:Animals, Newborn / Q000502:physiology*; D002364:Caseins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D004723:Endorphins / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D008297:Male; D008969:Molecular Sequence Data; D009068:Movement / Q000187:drug effects; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012119:Respiration / Q000187:drug effects; D012890:Sleep / Q000187:drug effects*; D014851:Wakefulness / Q000187:drug effects
D002364:Caseins; D004723:Endorphins; D009270:Naloxone; C021968:beta-casomorphins