A Peptide Found in Schizophrenia and Autism Causes Behavioral Changes in Rats

Abstract

In a previous study we showed that β-casomorphin-7 (β-CM7) is taken up by brain regions relevant to schizophrenia and autism. The present experiment was designed to find whether β-CM7 has any behavioral or analgesic effects in rats. About 65 seconds after treatment with different doses of β-CM7, rats became restless and ran violently, with teeth chattering and with rapid respiration. Seven minutes later, the rats became inactive with less walking, distancing themselves from the other rat in the same cage, and sitting in, or putting their head against, the corner of the cage. The sound response was reduced and social interaction was absent. One hour later, the rats showed hyperdefensiveness. The above behavioral effects of β-CM7 did not occur when rats were pretreated with naloxone (2 mg/kg, IP). The rats receiving saline did not show any behavioral changes throughout the 2 hour period of observation. β-CM7 also demonstrated analgesic effects, which could be blocked by naloxone. The results suggest that β-CM7 may play a role in behavioral disorders such as autism and schizophrenia.