Behavioral and neurobiological effects of the enkephalinase inhibitor RB101 relative to its antidepressant effects

Emily M. Jutkiewicz, Mary M. Torregrossa, Katarzyna Sobczyk-Kojiro, Henry I. Mosberg, John E. Folk, Kenner C. Rice, Stanley J. Watson, James H. Woods

Research output: Contribution to journalArticlepeer-review

37 Scopus citations


Nonpeptidic delta-opioid receptor agonists produce antidepressant-like effects in rodents, and compounds that inhibit the breakdown of endogenous opioid peptides have antidepressant-like effects in animal models. In this study, the behavioral effects of the enkephalinase inhibitor, RB101 (N-[(R, S)-2-benzyl-3-[(S)(2-amino-4-methyl-thio)-butyldithio]-1-oxopropyl] -l-phenylalanine benzyl ester), were examined. Specifically, the effects of RB101 on convulsive activity, locomotor activity, and antidepressant-like effects in the forced swim test were studied in Sprague-Dawley rats, and the opioid receptor types mediating these effects were examined by antagonist studies. In addition, the effects of RB101 on brain-derived neurotrophic factor (BDNF) mRNA expression were evaluated in relation to its antidepressant effects. RB101 produced delta-opioid receptor-mediated antidepressant effects (32 mg/kg i.v. and 100 mg/kg i.p.) and increased locomotor activity (32 mg/kg i.v.) in rats. RB101 did not produce convulsions or seizures and did not alter BDNF mRNA expression. In conclusion, RB101 has the potential to produce antidepressant effects without convulsions.

Original languageEnglish (US)
Pages (from-to)151-159
Number of pages9
JournalEuropean Journal of Pharmacology
Issue number1-3
StatePublished - Feb 15 2006
Externally publishedYes


  • (Rat)
  • Behavior
  • Brain-derived neurotrophic factor
  • Forced swim test
  • RB101

ASJC Scopus subject areas

  • Pharmacology


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