U50, 488 increases ultrasonic vocalizations in 3‐, 10‐, and 18‐day‐old rat pups in isolation and the home cage

Susan E. Carden, Lila Davachi, Myron A. Hofer

Research output: Contribution to journalArticle


Separation‐induced calling in the young of many species can be modulated by the opioid system. Morphine reduces ultrasonic vocalizations (USVs) produced by isolated rat pups, an effect blocked by naltrexone. Central administration of the mu and delta opiate receptor agonists DAMGO and DPDPE reduce USV; kappa receptor agonist U50,488 increases them. We now find that peripheral U50,488 not only boosted calling rates in isolated 3‐, 10‐, and 18‐day‐old rat pups, but also induced calling in pups of these ages tested in the home cage with their littermates, where USVs are seldom heard in nature. U50,488 lowered rectal temperature, although temperature loss and USV were not correlated within drug treatment groups.© 1994 John Wiley & Sons, Inc.

Original languageEnglish (US)
Pages (from-to)65-83
Number of pages19
JournalDevelopmental Psychobiology
Issue number1
StatePublished - Jan 1994


ASJC Scopus subject areas

  • Developmental and Educational Psychology
  • Developmental Neuroscience
  • Developmental Biology
  • Behavioral Neuroscience

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